WorldWideScience

Sample records for hydrogeological numerical model

  1. Numerical modeling of atoll island hydrogeology.

    Science.gov (United States)

    Bailey, R T; Jenson, J W; Olsen, A E

    2009-01-01

    We implemented Ayers and Vachers' (1986) inclusive conceptual model for atoll island aquifers in a comprehensive numerical modeling study to evaluate the response of the fresh water lens to selected controlling climatic and geologic variables. Climatic factors include both constant and time-varying recharge rates, with particular attention paid to the effects of El Niño and the associated drought it brings to the western Pacific. Geologic factors include island width; hydraulic conductivity of the uppermost Holocene-age aquifer, which contains the fresh water lens; the depth to the contact with the underlying, and much more conductive, Pleistocene karst aquifer, which transmits tidal signals to the base of the lens; and the presence or absence of a semiconfining reef flat plate on the ocean side. Sensitivity analyses of steady-steady simulations show that lens thickness is most strongly sensitive to the depth to the Holocene-Pleistocene contact and to the hydraulic conductivity of the Holocene aquifer, respectively. Comparisons between modeling results and published observations of atoll island lens thicknesses suggest a hydraulic conductivity of approximately 50 m/d for leeward islands and approximately 400 m/d for windward islands. Results of transient simulations show that lens thickness fluctuations during average seasonal conditions and El Niño events are quite sensitive to island width, recharge rate, and hydraulic conductivity of the Holocene aquifer. In general, the depletion of the lens during drought conditions is most drastic for small, windward islands. Simulation results suggest that recovery from a 6-month drought requires about 1.5 years.

  2. Numerical modeling of the hydrogeological effects of ONKALO in 2009

    International Nuclear Information System (INIS)

    Raemae, T.

    2011-10-01

    The underground rock characterization facility ONKALO is currently being excavated in the bedrock of the Olkiluoto Island. The construction work of the ONKALO begun in 2004 and the tunnel will remain open for the whole period of the operation of the planned repository for spent nuclear fuel. The open tunnels cause a disturbance on the local groundwater system. The leakage water flowing into the open tunnels withdraw water from the bedrock and locally alter the natural flow routes. One of the possible consequences of the convergent flow towards the ONKALO is that the highly saline deeper groundwater might be drawn towards the ONKALO, this process is called upconing. The purpose of this work is to estimate the possible upconing of the deep saline waters up to the repository level. A numerical flow and transport simulation is conducted with conservative approach to ensure overestimation of the effects of the ONKALO. In this study a 3D model of the hydrogeological system of the Olkiluoto is used as the basis for numerical flow and transport modeling of the saline groundwater movement in the bedrock of Olkiluoto. The numerical modelling is conducted using the commercial Comsol 3.5a code. The modelled geometry of the ONKALO includes the already excavated ONKALO and the extension according to the layout plan used in this work. The ONKALO and the hydrogeological zones are simplified for this study. In addition the used hydrogeological zones are modelled as 3D blocks with constant thickness of 50 meters. With the used boundary conditions upconing occurs even with the lowest leakage values. The influence of the leakage water is small on the maximum TDS-value at the depth near ONKALO. In this work this phenomenon is explained by the increase in the fresh water infiltration rate as the leakage water is increased, since the low density fresh water is transported more easily downwards than the high density saline water transported upwards towards the ONKALO. Further away from

  3. Linking Physical and Numerical Modelling in Hydrogeology Using Sand Tank Experiments and Comsol Multiphysics

    Science.gov (United States)

    Singha, Kamini; Loheide, Steven P., II

    2011-01-01

    Visualising subsurface processes in hydrogeology and building intuition for how these processes are controlled by changes in forcing is hard for many undergraduate students. While numerical modelling is one way to help undergraduate students explore outcomes of multiple scenarios, many codes are not user-friendly with respect to defining domains,…

  4. Numerical model for mapping of complex hydrogeological conditions: the Chmielnik area (South Poland) case study

    Science.gov (United States)

    Buszta, Kamila; Szklarczyk, Tadeusz; Malina, Grzegorz

    2017-04-01

    Detailed analysis of hydrogeological conditions at a study area is the basis for characterising adjacent groundwater circulation systems. It is also an essential element during executing hydrogeological documentations. The goal of this work was to reconstruct on a numerical model natural groundwater circulation systems of the studied area located within the municipality of Chmielnik in the region of Kielce (South Poland). The area is characterized by a complex geological structure, which along with the existing hydrographic network, makes the scheme of groundwater circulation complicated and difficult to map on a numerical model. The studied area is situated at the border of three geological units: on the North - the extended portion of the Palaeozoic Swietokrzyskie Mountains (mainly Devonian and Permian), in the center - the S-W part of the Mesozoic Margin of the Swietokrzyskie Mountains, and on the South - a marginal zone of the Carpathian Foredeep. The whole area belongs to the Vistula river basin, and it includes catchments of its left tributaries: the Nida and Czarna Staszowska rivers. Based on the collected field and archival hydrogeological, hydrological and sozological data a conceptual model was built, under which a numerical model of groundwater flow was developed using the specialized software - Visual MODFLOW. The numerical model maps the five-layer groundwater circulation system in conjunction with surface watercourses. Such division reflects appropriately the variability of hydrogeological parameters within the geological structures. Two principal and exploited aquifers comprise: a fractured-porous Neogene and fractured Upper Jurassic formations. The external model borders are based primarily on surface watercourses and locally on watersheds. The modelled area of 130 km2 was divided into square grids of 50 m. The model consists of 275 rows and 277 columns. Each of five layers was simulated with the same number of active blocks. In the construction of

  5. Hydrogeological conceptual model development and numerical modelling using CONNECTFLOW, Forsmark modelling stage 2.3

    Energy Technology Data Exchange (ETDEWEB)

    Follin, Sven (SF GeoLogic AB, Taeby (Sweden)); Hartley, Lee; Jackson, Peter; Roberts, David (Serco TAP (United Kingdom)); Marsic, Niko (Kemakta Konsult AB, Stockholm (Sweden))

    2008-05-15

    Three versions of a site descriptive model (SDM) have been completed for the Forsmark area. Version 0 established the state of knowledge prior to the start of the site investigation programme. Version 1.1 was essentially a training exercise and was completed during 2004. Version 1.2 was a preliminary site description and concluded the initial site investigation work (ISI) in June 2005. Three modelling stages are planned for the complete site investigation work (CSI). These are labelled stage 2.1, 2.2 and 2.3, respectively. An important component of each of these stages is to address and continuously try to resolve discipline-specific uncertainties of importance for repository engineering and safety assessment. Stage 2.1 included an updated geological model for Forsmark and aimed to provide a feedback from the modelling working group to the site investigation team to enable completion of the site investigation work. Stage 2.2 described the conceptual understanding and the numerical modelling of the bedrock hydrogeology in the Forsmark area based on data freeze 2.2. The present report describes the modelling based on data freeze 2.3, which is the final data freeze in Forsmark. In comparison, data freeze 2.3 is considerably smaller than data freeze 2.2. Therefore, stage 2.3 deals primarily with model confirmation and uncertainty analysis, e.g. verification of important hypotheses made in stage 2.2 and the role of parameter uncertainty in the numerical modelling. On the whole, the work reported here constitutes an addendum to the work reported in stage 2.2. Two changes were made to the CONNECTFLOW code in stage 2.3. These serve to: 1) improve the representation of the hydraulic properties of the regolith, and 2) improve the conditioning of transmissivity of the deformation zones against single-hole hydraulic tests. The changes to the modelling of the regolith were made to improve the consistency with models made with the MIKE SHE code, which involved the introduction

  6. Numerical modelling of levee stability based on coupled mechanical, thermal and hydrogeological processes

    Directory of Open Access Journals (Sweden)

    Dwornik Maciej

    2016-01-01

    Full Text Available The numerical modelling of coupled mechanical, thermal and hydrogeological processes for a soil levee is presented in the paper. The modelling was performed for a real levee that was built in Poland as a part of the ISMOP project. Only four parameters were changed to build different flood waves: the water level, period of water increase, period of water decrease, and period of low water level after the experiment. Results of numerical modelling shows that it is possible and advisable to calculate simultaneously changes of thermal and hydro-mechanical fields. The presented results show that it is also possible to use thermal sensors in place of more expensive pore pressure sensors, with some limitations. The results of stability analysis show that the levee is less stable when the water level decreases, after which factor of safety decreases significantly. For all flooding wave parameters described in the paper, the levee is very stable and factor of safety variations for any particular stage were not very large.

  7. Development of analytical and numerical models for the assessment and interpretation of hydrogeological field tests

    International Nuclear Information System (INIS)

    Mironenko, V.A.; Rumynin, V.G.; Konosavsky, P.K.; Pozdniakov, S.P.; Shestakov, V.M.; Roshal, A.A.

    1994-07-01

    Mathematical models of the flow and tracer tests in fractured aquifers are being developed for the further study of radioactive wastes migration in round water at the Lake Area, which is associated with one of the waste disposal site in Russia. The choice of testing methods, tracer types (chemical or thermal) and the appropriate models are determined by the nature of the ongoing ground-water pollution processes and the hydrogeological features of the site under consideration. Special importance is attached to the increased density of wastes as well as to the possible redistribution of solutes both in the liquid phase and in the absorbed state (largely, on fracture surfaces). This allows for studying physical-and-chemical (hydrogeochemical) interaction parameters which are hard to obtain (considering a fractured structure of the rock mass) in laboratory. Moreover, a theoretical substantiation is being given to the field methods of studying the properties of a fractured stratum aimed at the further construction of the drainage system or the subsurface flow barrier (cutoff wall), as well as the monitoring system that will evaluate the reliability of these ground-water protection measures. The proposed mathematical models are based on a tight combination of analytical and numerical methods, the former being preferred in solving the principal (2D axisymmetrical) class of the problems. The choice of appropriate problems is based on the close feedback with subsequent field tests in the Lake Area. 63 refs

  8. Development of analytical and numerical models for the assessment and interpretation of hydrogeological field tests

    Energy Technology Data Exchange (ETDEWEB)

    Mironenko, V.A.; Rumynin, V.G.; Konosavsky, P.K. [St. Petersburg Mining Inst. (Russian Federation); Pozdniakov, S.P.; Shestakov, V.M. [Moscow State Univ. (Russian Federation); Roshal, A.A. [Geosoft-Eastlink, Moscow (Russian Federation)

    1994-07-01

    Mathematical models of the flow and tracer tests in fractured aquifers are being developed for the further study of radioactive wastes migration in round water at the Lake Area, which is associated with one of the waste disposal site in Russia. The choice of testing methods, tracer types (chemical or thermal) and the appropriate models are determined by the nature of the ongoing ground-water pollution processes and the hydrogeological features of the site under consideration. Special importance is attached to the increased density of wastes as well as to the possible redistribution of solutes both in the liquid phase and in the absorbed state (largely, on fracture surfaces). This allows for studying physical-and-chemical (hydrogeochemical) interaction parameters which are hard to obtain (considering a fractured structure of the rock mass) in laboratory. Moreover, a theoretical substantiation is being given to the field methods of studying the properties of a fractured stratum aimed at the further construction of the drainage system or the subsurface flow barrier (cutoff wall), as well as the monitoring system that will evaluate the reliability of these ground-water protection measures. The proposed mathematical models are based on a tight combination of analytical and numerical methods, the former being preferred in solving the principal (2D axisymmetrical) class of the problems. The choice of appropriate problems is based on the close feedback with subsequent field tests in the Lake Area. 63 refs.

  9. Numerical groundwater-flow model of the Minnelusa and Madison hydrogeologic units in the Rapid City area, South Dakota

    Science.gov (United States)

    Putnam, Larry D.; Long, Andrew J.

    2009-01-01

    The city of Rapid City and other water users in the Rapid City area obtain water supplies from the Minnelusa and Madison aquifers, which are contained in the Minnelusa and Madison hydrogeologic units. A numerical groundwater-flow model of the Minnelusa and Madison hydrogeologic units in the Rapid City area was developed to synthesize estimates of water-budget components and hydraulic properties, and to provide a tool to analyze the effect of additional stress on water-level altitudes within the aquifers and on discharge to springs. This report, prepared in cooperation with the city of Rapid City, documents a numerical groundwater-flow model of the Minnelusa and Madison hydrogeologic units for the 1,000-square-mile study area that includes Rapid City and the surrounding area. Water-table conditions generally exist in outcrop areas of the Minnelusa and Madison hydrogeologic units, which form generally concentric rings that surround the Precambrian core of the uplifted Black Hills. Confined conditions exist east of the water-table areas in the study area. The Minnelusa hydrogeologic unit is 375 to 800 feet (ft) thick in the study area with the more permeable upper part containing predominantly sandstone and the less permeable lower part containing more shale and limestone than the upper part. Shale units in the lower part generally impede flow between the Minnelusa hydrogeologic unit and the underlying Madison hydrogeologic unit; however, fracturing and weathering may result in hydraulic connections in some areas. The Madison hydrogeologic unit is composed of limestone and dolomite that is about 250 to 610 ft thick in the study area, and the upper part contains substantial secondary permeability from solution openings and fractures. Recharge to the Minnelusa and Madison hydrogeologic units is from streamflow loss where streams cross the outcrop and from infiltration of precipitation on the outcrops (areal recharge). MODFLOW-2000, a finite-difference groundwater

  10. Regional hydrogeological simulations for Forsmark - numerical modelling using CONNECTFLOW. Preliminary site description Forsmark area - version 1.2

    Energy Technology Data Exchange (ETDEWEB)

    Hartley, Lee; Cox, Ian; Hunter, Fiona; Jackson, Peter; Joyce, Steve; Swift, Ben [Serco Assurance, Risley (United Kingdom); Gylling, Bjoern; Marsic, Niko [Kemakta Konsult AB, Stockholm (Sweden)

    2005-05-01

    The Swedish Nuclear Fuel and Waste Management Company (SKB) carries out site investigations in two different candidate areas in Sweden with the objective of describing the in-situ conditions for a bedrock repository for spent nuclear fuel. The site characterisation work is divided into two phases, an initial site investigation phase (IPLU) and a complete site investigation phase (KPLU). The results of IPLU are used as a basis for deciding on a subsequent KPLU phase. On the basis of the KPLU investigations a decision is made as to whether detailed characterisation will be performed (including sinking of a shaft). An integrated component in the site characterisation work is the development of site descriptive models. These comprise basic models in three dimensions with an accompanying text description. Central in the modelling work is the geological model, which provides the geometrical context in terms of a model of deformation zones and the rock mass between the zones. Using the geological and geometrical description models as a basis, descriptive models for other geo-disciplines (hydrogeology, hydro-geochemistry, rock mechanics, thermal properties and transport properties) will be developed. Great care is taken to arrive at a general consistency in the description of the various models and assessment of uncertainty and possible needs of alternative models. Here, a numerical model is developed on a regional-scale (hundreds of square kilometres) to understand the zone of influence for groundwater flow that affects the Forsmark area. Transport calculations are then performed by particle tracking from a local-scale release area (a few square kilometres) to identify potential discharge areas for the site and using greater grid resolution. The main objective of this study is to support the development of a preliminary Site Description of the Forsmark area on a regional-scale based on the available data of 30 June 2004 and the previous Site Description. A more specific

  11. Regional hydrogeological simulations. Numerical modelling using ConnectFlow. Preliminary site description Simpevarp sub area - version 1.2

    Energy Technology Data Exchange (ETDEWEB)

    Hartley, Lee; Hoch, Andrew; Hunter, Fiona; Jackson, Peter [Serco Assurance, Risley (United Kingdom); Marsic, Niko [Kemakta Konsult, Stockholm (Sweden)

    2005-02-01

    The Swedish Nuclear Fuel and Waste Management Company (SKB) carries out site investigations in two different candidate areas in Sweden with the objective of describing the in situ conditions for a bedrock repository for spent nuclear fuel. The two candidate areas are named Forsmark and Simpevarp. The site characterisation work is divided into two phases, an initial site investigation phase (IPLU) and a complete site investigation phase (KPLU). The results of IPLU are used as a basis for deciding on a subsequent KPLU phase. On the basis of the KPLU investigations a decision is made as to whether detailed characterisation will be performed (including sinking of a shaft).An integrated component in the site characterisation work is the development of site descriptive models. These comprise basic models in three dimensions with an accompanying text description. Central in the modelling work is the geological model which provides the geometrical context in terms of a model of deformation zones and the rock mass between the zones. Using the geological and geometrical description models as a basis, descriptive models for other geo-disciplines (hydrogeology, hydro-geochemistry, rock mechanics, thermal properties and transport properties) will be developed. Great care is taken to arrive at a general consistency in the description of the various models and assessment of uncertainty and possible needs of alternative models.Here, a numerical model is developed on a regional-scale (hundreds of square kilometres) to understand the zone of influence for groundwater flow that effects the Simpevarp area. Transport calculations are then performed by particle tracking from a local-scale release area (tens of square kilometres) to identify potential discharge areas for the site. The transport from the two site-scale release areas (a few square kilometres) at the Simpevarp site and the Laxemar site are also considered more specifically and using greater grid resolution.The main

  12. Regional hydrogeological simulations for Forsmark - numerical modelling using DarcyTools. Preliminary site description Forsmark area version 1.2

    International Nuclear Information System (INIS)

    Follin, Sven; Stigsson, Martin; Svensson, Urban

    2005-12-01

    A numerical model is developed on a regional-scale (hundreds of square kilometres) to study the zone of influence for variable-density groundwater flow that affects the Forsmark area. Transport calculations are performed by particle tracking from a local-scale release area (a few square kilometres) to test the sensitivity to different hydrogeological uncertainties and the need for far-field realism. The main objectives of the regional flow modelling were to achieve the following: I. Palaeo-hydrogeological understanding: An improved understanding of the palaeohydrogeological conditions is necessary in order to gain credibility for the site descriptive model in general and the hydrogeological description in particular. This requires modelling of the groundwater flow from the last glaciation up to present-day with comparisons against measured TDS and other hydro-geochemical measures. II. Simulation of flow paths: The simulation and visualisation of flow paths from a tentative repository area is a means for describing the role of the current understanding of the modelled hydrogeological conditions in the target volume, i.e. the conditions of primary interest for Safety Assessment. Of particular interest here is demonstration of the need for detailed far-field realism in the numerical simulations. The motivation for a particular model size (and resolution) and set of boundary conditions for a realistic description of the recharge and discharge connected to the flow at repository depth is an essential part of the groundwater flow path simulations. The numerical modelling was performed by two separate modelling teams, the ConnectFlow Team and the DarcyTools Team. The work presented in this report was based on the computer code DarcyTools developed by Computer-aided Fluid Engineering. DarcyTools is a kind of equivalent porous media (EPM) flow code specifically designed to treat flow and salt transport in sparsely fractured crystalline rock intersected by transmissive

  13. Regional hydrogeological simulations for Forsmark - numerical modelling using DarcyTools. Preliminary site description Forsmark area version 1.2

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-12-15

    A numerical model is developed on a regional-scale (hundreds of square kilometres) to study the zone of influence for variable-density groundwater flow that affects the Forsmark area. Transport calculations are performed by particle tracking from a local-scale release area (a few square kilometres) to test the sensitivity to different hydrogeological uncertainties and the need for far-field realism. The main objectives of the regional flow modelling were to achieve the following: I. Palaeo-hydrogeological understanding: An improved understanding of the palaeohydrogeological conditions is necessary in order to gain credibility for the site descriptive model in general and the hydrogeological description in particular. This requires modelling of the groundwater flow from the last glaciation up to present-day with comparisons against measured TDS and other hydro-geochemical measures. II. Simulation of flow paths: The simulation and visualisation of flow paths from a tentative repository area is a means for describing the role of the current understanding of the modelled hydrogeological conditions in the target volume, i.e. the conditions of primary interest for Safety Assessment. Of particular interest here is demonstration of the need for detailed far-field realism in the numerical simulations. The motivation for a particular model size (and resolution) and set of boundary conditions for a realistic description of the recharge and discharge connected to the flow at repository depth is an essential part of the groundwater flow path simulations. The numerical modelling was performed by two separate modelling teams, the ConnectFlow Team and the DarcyTools Team. The work presented in this report was based on the computer code DarcyTools developed by Computer-aided Fluid Engineering. DarcyTools is a kind of equivalent porous media (EPM) flow code specifically designed to treat flow and salt transport in sparsely fractured crystalline rock intersected by transmissive

  14. Quantification of the electrical anisotropy in the pro­cess of numerical modelling for hydrogeological characterization

    Science.gov (United States)

    Gernez, S.; Bouchedda, A.; Gloaguen, E.; Paradis, D.

    2017-12-01

    In order to understand groundwater flow and contaminant transport in the subsurface, it is important to characterize accurately its permeability. Hydrogeophysics, which involves the use of geophysical data to infer the hydraulic properties of the subsurface, is a relatively new geoscience field that is promising to improve hydrogeological characterization. Amongst existing geophysical methods, Electrical Resistivity Tomography (ERT), that can cover a large continuous underground surface or volume, has been widely applied. The inversed electrical resistivities obtained are related to the permeabilities by different means and the resistivity anisotropy should theoretically be a proxy to the permeability anisotropy. However, the existing hydrogeophysical inversion tools usually do not take into account anisotropy. In this paper, we present an anisotropic forward- and inverse-problem 2.5D finite-differences electrical study, which allows to produce improved anisotropic permeability characterization models. We first detail the theoretical basis of the anisotropic ERT, which introduces a resistivity tensor in place of a scalar, and its numerical implementation. After that, we build a synthetic case presenting a simple but representative geological structure in two horizontal homogeneous and anisotropic beds: the numerical forward modelling shows a difference of less than 1% with the analytical solution; the inverse modelling is able to reproduce the initial structure well, with resistivity values close to the initial synthetic model (see attached figure). We show that by using both surface and single-borehole arrays, we overcome the equivalence principle making sure that a unique solution arises. The latter cannot be obtained when considering the media isotropic as typically assumed with existing inversion tools. Finally, we discuss the consequences of the integration of anisotropy in the data-integrated characterization of the permeability. We show that it has a

  15. Representing Glaciations and Subglacial Processes in Hydrogeological Models: A Numerical Investigation

    Directory of Open Access Journals (Sweden)

    Arnaud Sterckx

    2017-01-01

    Full Text Available The specific impact of glacial processes on groundwater flow and solute transport under ice-sheets was determined by means of numerical simulations. Groundwater flow and the transport of δ18O, TDS, and groundwater age were simulated in a generic sedimentary basin during a single glacial event followed by a postglacial period. Results show that simulating subglacial recharge with a fixed flux boundary condition is relevant only for small fluxes, which could be the case under partially wet-based ice-sheets. Glacial loading decreases overpressures, which appear only in thick and low hydraulic diffusivity layers. If subglacial recharge is low, glacial loading can lead to underpressures after the retreat of the ice-sheet. Isostasy reduces considerably the infiltration of meltwater and the groundwater flow rates. Below permafrost, groundwater flow is reduced under the ice-sheet but is enhanced beyond the ice-sheet front. Accounting for salinity-dependent density reduces the infiltration of meltwater at depth. This study shows that each glacial process is potentially relevant in models of subglacial groundwater flow and solute transport. It provides a good basis for building and interpreting such models in the future.

  16. Representing glaciations and subglacial processes in hydrogeological models : a numerical investigation

    OpenAIRE

    Sterckx, Arnaud; Lemieux, Jean-Michel; Vaikmäe, Rein

    2017-01-01

    The specific impact of glacial processes on groundwater flow and solute transport under ice-sheets was determined by means of numerical simulations. Groundwater flow and the transport of δ18O, TDS, and groundwater age were simulated in a generic sedimentary basin during a single glacial event followed by a postglacial period. Results show that simulating subglacial recharge with a fixed flux boundary condition is relevant only for small fluxes, which could be the case under partially wet-base...

  17. Testing and validation of numerical models of groundwater flow, solute transport and chemical reactions in fractured granites: A quantitative study of the hydrogeological and hydrochemical impact produced

    Energy Technology Data Exchange (ETDEWEB)

    Molinero Huguet, J

    2001-07-01

    This work deals with numerical modeling of groundwater flow, solute transport and chemical reactions through fractured media. These models have been developed within the framework of research activities founded by ENRESA , the Spanish Company for Nuclear Waste Management. This project is the result of a collaborative agreement between ENRESA and his equivalent Swedish Company (SKB) through the research project Task Force 5 of the Aspo Underground Laboratory. One of the objectives of this project is to assess quantitatively th hydrogeological and hydrochemical impact produced by the construction of a Deep Geological Repository in fractured granites. This is important because the new conditions altered construction impact will constitute the initial conditions for the repository closure stage. A second goo l of this work deals with testing the ability of current numerical tools to cope simultaneously with the complex hydrogeological and hydrochemical settlings, which are expected to take place in actual nuclear waste underground repositories constructed in crystalline fractured bed racks. This study has been undertaken through the performance of numerical models, which have subsequently been applied to simulate the hydrogeological and hydrochemical behavior of a granite massif, at a kilo metrical scale, during construction of the Aspo Hard Rock Underground Laboratory (Sweden). The Aspo Hard Rock Laboratory is a prototype, full-scale underground facility launched and operated by SKB. The main aim of the laboratory is to provide an opportunity for research, development and demonstration in a realistic rock environment down to the depth planned for the future deep repository. The framework of this underground facility provides a unique opportunity to attempt the objectives of the present dissertation. (Author)

  18. Testing and validation of numerical models of groundwater flow, solute transport and chemical reactions in fractured granites: A quantitative study of the hydrogeological and hydrochemical impact produced

    International Nuclear Information System (INIS)

    Molinero Huguet, J.

    2001-06-01

    This work deals with numerical modeling of groundwater flow, solute transport and chemical reactions through fractured media. These models have been developed within the framework of research activities founded by ENRESA , the Spanish Company for Nuclear Waste Management. This project is the result of a collaborative agreement between ENRESA and his equivalent Swedish Company (SKB) through the research project Task Force 5 of the Aspo Underground Laboratory. One of the objectives of this project is to assess quantitatively th hydrogeological and hydrochemical impact produced by the construction of a Deep Geological Repository in fractured granites. This is important because the new conditions altered construction impact will constitute the initial conditions for the repository closure stage. A second goo l of this work deals with testing the ability of current numerical tools to cope simultaneously with the complex hydrogeological and hydrochemical settlings, which are expected to take place in actual nuclear waste underground repositories constructed in crystalline fractured bed racks. This study has been undertaken through the performance of numerical models, which have subsequently been applied to simulate the hydrogeological and hydrochemical behavior of a granite massif, at a kilo metrical scale, during construction of the Aspo Hard Rock Underground Laboratory (Sweden). The Aspo Hard Rock Laboratory is a prototype, full-scale underground facility launched and operated by SKB. The main aim of the laboratory is to provide an opportunity for research, development and demonstration in a realistic rock environment down to the depth planned for the future deep repository. The framework of this underground facility provides a unique opportunity to attempt the objectives of the present dissertation. (Author)

  19. Current status of regional hydrogeological studies and numerical simulations on geological disposal

    International Nuclear Information System (INIS)

    Nakao, Shinsuke; Kikuchi, Tsuneo; Ishido, Tsuneo

    2004-01-01

    Current status of regional hydrogeological studies on geological disposal including hydrogeological modeling using numerical simulators is reviewed in this report. A regional scale and boundary conditions of numerical models are summarized mainly from the results of the RHS (regional hydrogeological study) project conducted by Japan Nuclear Cycle Development Institute (JNC) in the Tono area. We also refer to the current conceptual modes of hydrology and numerical models of unsaturated zone flow at Yucca Mountain, Nevada, which is the arid site proposed for consideration as the United States' first underground high-level radioactive waste repository. Understanding behavior of a freshwater-saltwater transition zone seems to play a key role in the hydrogeological modeling in a coastal region. Technical features of a numerical simulator as a tool for geothermal reservoir modeling is also briefly described. (author)

  20. Regional hydrogeological conceptual model of candidate Beishan area for high level radioactive waste disposal repository

    International Nuclear Information System (INIS)

    Wang Hailong; Guo Yonghai

    2014-01-01

    The numerical modeling of groundwater flow is an important aspect of hydrogeological assessment in siting of a high level radioactive waste disposal repository. Hydrogeological conceptual model is the basic and premise of numerical modeling of groundwater flow. Based on the hydrogeological analysis of candidate Beishan area, surface water system was created by using DEM data and the modeling area is determined. Three-dimensional hydrogeological structure model was created through GMS software. On the basis of analysis and description of boundary condition, flow field, groundwater budget and hydrogeological parameters, hydrogeological conceptual model was set up for the Beishan area. (authors)

  1. Numerical modelling of surface hydrology and near-surface hydrogeology at Forsmark. Site descriptive modelling SDM. Site Forsmark

    Energy Technology Data Exchange (ETDEWEB)

    Bosson, Emma (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)); Gustafsson, Lars-Goeran; Sassner, Mona (DHI Sverige AB, Stockholm (Sweden))

    2008-09-15

    SKB is currently performing site investigations at two potential sites for a final repository for spent nuclear fuel. This report presents results of water flow and solute transport modelling of the Forsmark site. The modelling reported in this document focused on the near-surface groundwater, i.e. groundwater in Quaternary deposits and shallow rock, and surface water systems, and was performed using the MIKE SHE tool. The most recent site data used in the modelling were delivered in the Forsmark 2.3 dataset, which had its 'data freeze' on March 31, 2007. The present modelling is performed in support of the final version of the Forsmark site description that is produced during the site investigation phase. In this work, the hydrological modelling system MIKE SHE has been used to describe near-surface groundwater flow and the contact between groundwater and surface water at the Forsmark site. The surface water system at Forsmark is described with the one-dimensional 'channel flow' modelling tool MIKE 11, which is fully and dynamically integrated with MIKE SHE. The MIKE SHE model was updated with data from the F2.3 data freeze. The main updates concerned the geological description of the saturated zone and the time series data on water levels and surface water discharges. The time series data used as input data and for calibration and validation was extended until the Forsmark 2.3 data freeze (March 31, 2007). The present work can be subdivided into the following four parts: 1. Update of the numerical flow model. 2. Sensitivity analysis and calibration of the model parameters. 3. Validation of the calibrated model, followed by evaluation and identification of discrepancies between measurements and model results. 4. Additional sensitivity analysis and calibration in order to resolve the problems identified in point three above. The main actions taken during the calibration can be summarised as follows: 1. The potential evapotranspiration was

  2. Implementation and use of Gaussian process meta model for sensitivity analysis of numerical models: application to a hydrogeological transport computer code

    International Nuclear Information System (INIS)

    Marrel, A.

    2008-01-01

    In the studies of environmental transfer and risk assessment, numerical models are used to simulate, understand and predict the transfer of pollutant. These computer codes can depend on a high number of uncertain input parameters (geophysical variables, chemical parameters, etc.) and can be often too computer time expensive. To conduct uncertainty propagation studies and to measure the importance of each input on the response variability, the computer code has to be approximated by a meta model which is build on an acceptable number of simulations of the code and requires a negligible calculation time. We focused our research work on the use of Gaussian process meta model to make the sensitivity analysis of the code. We proposed a methodology with estimation and input selection procedures in order to build the meta model in the case of a high number of inputs and with few simulations available. Then, we compared two approaches to compute the sensitivity indices with the meta model and proposed an algorithm to build prediction intervals for these indices. Afterwards, we were interested in the choice of the code simulations. We studied the influence of different sampling strategies on the predictiveness of the Gaussian process meta model. Finally, we extended our statistical tools to a functional output of a computer code. We combined a decomposition on a wavelet basis with the Gaussian process modelling before computing the functional sensitivity indices. All the tools and statistical methodologies that we developed were applied to the real case of a complex hydrogeological computer code, simulating radionuclide transport in groundwater. (author) [fr

  3. A discussion on validation of hydrogeological models

    International Nuclear Information System (INIS)

    Carrera, J.; Mousavi, S.F.; Usunoff, E.J.; Sanchez-Vila, X.; Galarza, G.

    1993-01-01

    Groundwater flow and solute transport are often driven by heterogeneities that elude easy identification. It is also difficult to select and describe the physico-chemical processes controlling solute behaviour. As a result, definition of a conceptual model involves numerous assumptions both on the selection of processes and on the representation of their spatial variability. Validating a numerical model by comparing its predictions with actual measurements may not be sufficient for evaluating whether or not it provides a good representation of 'reality'. Predictions will be close to measurements, regardless of model validity, if these are taken from experiments that stress well-calibrated model modes. On the other hand, predictions will be far from measurements when model parameters are very uncertain, even if the model is indeed a very good representation of the real system. Hence, we contend that 'classical' validation of hydrogeological models is not possible. Rather, models should be viewed as theories about the real system. We propose to follow a rigorous modeling approach in which different sources of uncertainty are explicitly recognized. The application of one such approach is illustrated by modeling a laboratory uranium tracer test performed on fresh granite, which was used as Test Case 1b in INTRAVAL. (author)

  4. Hydrogeological structure model of the Olkiluoto Site. Update in 2010

    International Nuclear Information System (INIS)

    Vaittinen, T.; Ahokas, H.; Nummela, J.; Paulamaeki, S.

    2011-09-01

    As part of the programme for the final disposal of spent nuclear fuel, a hydrogeological structure model containing the hydraulically significant zones on Olkiluoto Island has been compiled. The structure model describes the deterministic site scale zones that dominate the groundwater flow. The main objective of the study is to provide the geometry and the hydrogeological properties related to the groundwater flow for the zones and the sparsely fractured bedrock to be used in the numerical modelling of groundwater flow and geochemical transport and thereby in the safety assessment. Also, these zones should be taken into account in the repository layout and in the construction of the disposal facility and they have a long-term impact on the evolution of the site and the safety of the disposal repository. The previous hydrogeological model was compiled in 2008 and this updated version is based on data available at the end of May 2010. The updating was based on new hydrogeological observations and a systematic approach covering all drillholes to assess measured fracture transmissivities typical of the site-scale hydrogeological zones. New data consisted of head observations and interpreted pressure and flow responses caused by field activities. Essential background data for the modelling included the ductile deformation model and the site scale brittle deformation zones modelled in the geological model version 2.0. The GSM combine both geological and geophysical investigation data on the site. As a result of the modelling campaign, hydrogeological zones HZ001, HZ008, HZ19A, HZ19B, HZ19C, HZ20A, HZ20B, HZ21, HZ21B, HZ039, HZ099, OL-BFZ100, and HZ146 were included in the structure model. Compared with the previous model, zone HZ004 was replaced with zone HZ146 and zone HZ039 was introduced for the first time. Alternative zone HZ21B was included in the basic model. For the modelled zones, both the zone intersections, describing the fractures with dominating groundwater

  5. HydroCube: an entity-relationship hydrogeological data model

    Science.gov (United States)

    Wojda, Piotr; Brouyère, Serge; Derouane, Johan; Dassargues, Alain

    2010-12-01

    Managing, handling and accessing hydrogeological information depends heavily on the applied hydrogeological data models, which differ between institutions and countries. The effective dissemination of hydrogeological information requires the convergence of such models to make hydrogeological information accessible to multiple users such as universities, water suppliers, and administration and research organisations. Furthermore, because hydrogeological studies are complex, they require a wide variety of high-quality hydrogeological data with appropriate metadata in clearly designed and coherent structures. A need exists, therefore, to develop and implement hydrogeological data models that cover, as much as possible, the full hydrogeological domain. A new data model, called HydroCube, was developed for the Walloon Region in Belgium in 2005. The HydroCube model presents an innovative holistic project-based approach which covers a full set of hydrogeological concepts and features, allowing for effective hydrogeological project management. The model stores data relating to the project locality, hydrogeological equipment, and related observations and measurements. In particular, it focuses on specialized hydrogeological field experiments such as pumping and tracer tests. This logical data model uses entity-relationship diagrams and it has been implemented in the Microsoft Access environment. It has been enriched with a fully functional user interface.

  6. Use of stratigraphic, petrographic, hydrogeologic and geochemical information for hydrogeologic modelling based on geostatistical simulation

    International Nuclear Information System (INIS)

    Rohlig, K.J.; Fischer, H.; Poltl, B.

    2004-01-01

    This paper describes the stepwise utilization of geologic information from various sources for the construction of hydrogeological models of a sedimentary site by means of geostatistical simulation. It presents a practical application of aquifer characterisation by firstly simulating hydrogeological units and then the hydrogeological parameters. Due to the availability of a large amount of hydrogeological, geophysical and other data and information, the Gorleben site (Northern Germany) has been used for a case study in order to demonstrate the approach. The study, which has not yet been completed, tries to incorporate as much as possible of the available information and to characterise the remaining uncertainties. (author)

  7. Simulation of hydrodynamic effects of salt rejection due to permafrost. Hydrogeological numerical model of density-driven mixing, at a regional scale, due to a high salinity pulse

    International Nuclear Information System (INIS)

    Vidstrand, Patrik; Svensson, Urban; Follin, Sven

    2006-10-01

    The main objective of this study is to support the safety assessment of the investigated candidate sites concerning hydrogeological and hydrogeochemical issues related to permafrost. However, a more specific objective of the study is to improve the assessment of processes in relation to permafrost scenarios. The model is based on a mathematical model that includes Darcy velocities, mass conservation, matrix diffusion, and salinity distribution. Gravitational effects are thus fully accounted for. A regional groundwater flow model (POM v1.1, Simpevarp) was used as basis for the simulations. The main results of the model include salinity distributions in time. The general conclusion is that density-driven mixing processes are contained within more permeable deformation zones and that these processes are fast as compared with preliminary permafrost growth rates. The results of the simulation suggest that a repository volume in the rock mass in-between the deterministic deformation zones, approximately 150 m below the permafrost will not experience a high salinity situation due to the salt rejection process

  8. Three-dimensional hydrogeologic framework model for use with a steady-state numerical ground-water flow model of the Death Valley regional flow system, Nevada and California

    International Nuclear Information System (INIS)

    Belcher, W.R.; Faunt, C.C.; D'Agnese, F.A.

    2002-01-01

    The U.S. Geological Survey, in cooperation with the Department of Energy and other Federal, State, and local agencies, is evaluating the hydrogeologic characteristics of the Death Valley regional ground-water flow system. The ground-water flow system covers and area of about 100,000 square kilometers from latitude 35 degrees to 38 degrees 15 minutes North to longitude 115 degrees to 118 degrees West, with the flow system proper comprising about 45,000 square kilometers. The Death Valley regional ground-water flow system is one of the larger flow systems within the Southwestern United States and includes in its boundaries the Nevada Test Site, Yucca Mountain, and much of Death Valley. Part of this study includes the construction of a three-dimensional hydrogeologic framework model to serve as the foundation for the development of a steady-state regional ground-water flow model. The digital framework model provides a computer-based description of the geometry and composition of the hydro geologic units that control regional flow. The framework model of the region was constructed by merging two previous framework models constructed for the Yucca Mountain Project and the Environmental Restoration Program Underground Test Area studies at the Nevada Test Site. The hydrologic characteristics of the region result from a currently arid climate and complex geology. Interbasinal regional ground-water flow occurs through a thick carbonate-rock sequence of Paleozoic age, a locally thick volcanic-rock sequence of Tertiary age, and basin-fill alluvium of Tertiary and Quaternary age. Throughout the system, deep and shallow ground-water flow may be controlled by extensive and pervasive regional and local faults and fractures. The framework model was constructed using data from several sources to define the geometry of the regional hydrogeologic units. These data sources include (1) a 1:250,000-scale hydrogeologic-map compilation of the region; (2) regional-scale geologic cross

  9. Fault zone hydrogeology

    Science.gov (United States)

    Bense, V. F.; Gleeson, T.; Loveless, S. E.; Bour, O.; Scibek, J.

    2013-12-01

    Deformation along faults in the shallow crust (research effort of structural geologists and hydrogeologists. However, we find that these disciplines often use different methods with little interaction between them. In this review, we document the current multi-disciplinary understanding of fault zone hydrogeology. We discuss surface- and subsurface observations from diverse rock types from unlithified and lithified clastic sediments through to carbonate, crystalline, and volcanic rocks. For each rock type, we evaluate geological deformation mechanisms, hydrogeologic observations and conceptual models of fault zone hydrogeology. Outcrop observations indicate that fault zones commonly have a permeability structure suggesting they should act as complex conduit-barrier systems in which along-fault flow is encouraged and across-fault flow is impeded. Hydrogeological observations of fault zones reported in the literature show a broad qualitative agreement with outcrop-based conceptual models of fault zone hydrogeology. Nevertheless, the specific impact of a particular fault permeability structure on fault zone hydrogeology can only be assessed when the hydrogeological context of the fault zone is considered and not from outcrop observations alone. To gain a more integrated, comprehensive understanding of fault zone hydrogeology, we foresee numerous synergistic opportunities and challenges for the discipline of structural geology and hydrogeology to co-evolve and address remaining challenges by co-locating study areas, sharing approaches and fusing data, developing conceptual models from hydrogeologic data, numerical modeling, and training interdisciplinary scientists.

  10. Bedrock hydrogeology Forsmark. Site descriptive modelling, SDM-Site Forsmark

    Energy Technology Data Exchange (ETDEWEB)

    Follin, Sven (SF GeoLogic AB, Taeby (Sweden))

    2008-12-15

    The Swedish Nuclear Fuel and Waste Management Company (SKB) has conducted site investigations at two different locations, the Forsmark and Laxemar-Simpevarp areas, with the objective of siting a final repository for spent nuclear fuel according to the KBS-3 concept. Site characterisation should provide all data required for an integrated evaluation of the suitability of the investigated site and an important component in the characterisation work is the development of a hydrogeological model. The hydrogeological model is used by repository engineering to design the underground facility and to develop a repository layout adapted to the site. It also provides input to the safety assessment. Another important use of the hydrogeological model is in the environmental impact assessment. This report presents the understanding of the hydrogeological conditions of the bedrock at Forsmark reached following the completion of the surface-based investigations and provides a summary of the bedrock hydrogeological model and the underlying data supporting its development. It constitutes the main reference on bedrock hydrogeology for the site descriptive model concluding the surface-based investigations at Forsmark, SDM-site, and is intended to describe the hydraulic properties and hydrogeological conditions of the bedrock at the site and to give the information essential for demonstrating understanding

  11. Bedrock Hydrogeology - Groundwater flow modelling. Site investigation SFR

    Energy Technology Data Exchange (ETDEWEB)

    Oehman, Johan [Geosigma AB, Uppsala (Sweden); Follin, Sven [SF GeoLogic AB, Taeby (Sweden); Oden, Magnus [SKB, Stockholm (Sweden)

    2013-05-15

    The hydrogeological model developed for the SFR extension project (PSU) consists of 40 geologically modelled deformation zones (DZ) and 8 sub-horizontal structural-hydraulic features, called SBAstructures, not defined in the geological model. However, some of the SBA-structures coincide with what is defined as unresolved possible deformation zones (Unresolved PDZ) in the geological modelling. In addition, the hydrogeological model consists of a stochastic discrete fracture network (DFN) model intended for the less fractured rock mass volumes (fracture domains) between the zones and the SBA-structures, and a stochastic fracture model intended to handle remaining Unresolved PDZs in the geological modelling not modelled as SBA-structures in the hydrogeological modelling. The four structural components of the bedrock in the hydrogeological model, i.e. DZ, SBA, Unresolved PDZ and DFN, are assigned hydraulic properties in the hydrogeological model based on the transmissivities interpreted from single-hole hydraulic tests. The main objective of the present work is to present the characteristics of the hydrogeological model with regard to the needs of the forthcoming safety assessment SR-PSU. In concrete words, simulated data are compared with measured data, i.e. hydraulic heads in boreholes and tunnel inflow to the existing repository (SFR). The calculations suggest that the available data for flow model calibration cannot be used to motivate a substantial adjustment of the initial hydraulic parameterisation (assignment of hydraulic properties) of the hydrogeological model. It is suggested that uncertainties in the hydrogeological model are studied in the safety assessment SR-PSU by means of a large number of calculation cases. These should address hydraulic heterogeneity of deterministic structures (DZ and SBA) and realisations of stochastic fractures/fracture networks (Unresolved PDZ and DFN) within the entire SFR Regional model domain.

  12. Bedrock Hydrogeology-Groundwater flow modelling. Site investigation SFR

    International Nuclear Information System (INIS)

    Oehman, Johan; Follin, Sven; Oden, Magnus

    2013-05-01

    The hydrogeological model developed for the SFR extension project (PSU) consists of 40 geologically modelled deformation zones (DZ) and 8 sub-horizontal structural-hydraulic features, called SBAstructures, not defined in the geological model. However, some of the SBA-structures coincide with what is defined as unresolved possible deformation zones (Unresolved PDZ) in the geological modelling. In addition, the hydrogeological model consists of a stochastic discrete fracture network (DFN) model intended for the less fractured rock mass volumes (fracture domains) between the zones and the SBA-structures, and a stochastic fracture model intended to handle remaining Unresolved PDZs in the geological modelling not modelled as SBA-structures in the hydrogeological modelling. The four structural components of the bedrock in the hydrogeological model, i.e. DZ, SBA, Unresolved PDZ and DFN, are assigned hydraulic properties in the hydrogeological model based on the transmissivities interpreted from single-hole hydraulic tests. The main objective of the present work is to present the characteristics of the hydrogeological model with regard to the needs of the forthcoming safety assessment SR-PSU. In concrete words, simulated data are compared with measured data, i.e. hydraulic heads in boreholes and tunnel inflow to the existing repository (SFR). The calculations suggest that the available data for flow model calibration cannot be used to motivate a substantial adjustment of the initial hydraulic parameterisation (assignment of hydraulic properties) of the hydrogeological model. It is suggested that uncertainties in the hydrogeological model are studied in the safety assessment SR-PSU by means of a large number of calculation cases. These should address hydraulic heterogeneity of deterministic structures (DZ and SBA) and realisations of stochastic fractures/fracture networks (Unresolved PDZ and DFN) within the entire SFR Regional model domain

  13. Hydrogeological modelling for migration of radioactivity

    International Nuclear Information System (INIS)

    Sunny, Faby; Chopra, Manish; Oza, R.B.

    2016-01-01

    The hydrogeological modelling for migration of radionuclides basically involves modelling of groundwater flow and contaminant transport through the groundwater. The water that occurs below the land surface or within the lithosphere is called groundwater. The groundwater constitutes about 4 % of the total water on the earth and about 30 % of freshwater on the earth. Groundwater models describe groundwater flow and contaminant transport processes using mathematical equations that are based on certain simplifying assumptions. These assumptions typically involve the direction of flow, geometry of the aquifer, the heterogeneity or anisotropy of sediments or bedrock within the aquifer, the contaminant transport mechanisms and chemical reactions. Because of the simplifying assumptions and the many uncertainties in the values of data, a model must be viewed as an approximation and not an exact duplication of field conditions. However, these models are useful investigation tool for a number of applications such as prediction of the possible fate and migration of contaminants for risk evaluation; tracking the possible pathway of groundwater contamination; evaluation of design of hydraulic containment and pump-and-treat systems; design of groundwater monitoring networks; evaluation of regional groundwater resources and prediction of the effect of future groundwater withdrawals on groundwater levels

  14. Manual on mathematical models in isotope hydrogeology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-10-01

    Methodologies based on the use of naturally occurring isotopes are, at present, an integral part of studies being undertaken for water resources assessment and management. Quantitative evaluations based on the temporal and/or spatial distribution of different isotopic species in hydrological systems require conceptual mathematical formulations. Different types of model can be employed depending on the nature of the hydrological system under investigation, the amount and type of data available, and the required accuracy of the parameter to be estimated. This manual provides an overview of the basic concepts of existing modelling approaches, procedures for their application to different hydrological systems, their limitations and data requirements. Guidance in their practical applications, illustrative case studies and information on existing PC software are also included. While the subject matter of isotope transport modelling and improved quantitative evaluations through natural isotopes in water sciences is still at the development stage, this manual summarizes the methodologies available at present, to assist the practitioner in the proper use within the framework of ongoing isotope hydrological field studies. In view of the widespread use of isotope methods in groundwater hydrology, the methodologies covered in the manual are directed towards hydrogeological applications, although most of the conceptual formulations presented would generally be valid. Refs, figs, tabs.

  15. Manual on mathematical models in isotope hydrogeology

    International Nuclear Information System (INIS)

    1996-10-01

    Methodologies based on the use of naturally occurring isotopes are, at present, an integral part of studies being undertaken for water resources assessment and management. Quantitative evaluations based on the temporal and/or spatial distribution of different isotopic species in hydrological systems require conceptual mathematical formulations. Different types of model can be employed depending on the nature of the hydrological system under investigation, the amount and type of data available, and the required accuracy of the parameter to be estimated. This manual provides an overview of the basic concepts of existing modelling approaches, procedures for their application to different hydrological systems, their limitations and data requirements. Guidance in their practical applications, illustrative case studies and information on existing PC software are also included. While the subject matter of isotope transport modelling and improved quantitative evaluations through natural isotopes in water sciences is still at the development stage, this manual summarizes the methodologies available at present, to assist the practitioner in the proper use within the framework of ongoing isotope hydrological field studies. In view of the widespread use of isotope methods in groundwater hydrology, the methodologies covered in the manual are directed towards hydrogeological applications, although most of the conceptual formulations presented would generally be valid. Refs, figs, tabs

  16. Evaluation of Uncertainties in hydrogeological modeling and groundwater flow analyses. Model calibration

    International Nuclear Information System (INIS)

    Ijiri, Yuji; Ono, Makoto; Sugihara, Yutaka; Shimo, Michito; Yamamoto, Hajime; Fumimura, Kenichi

    2003-03-01

    This study involves evaluation of uncertainty in hydrogeological modeling and groundwater flow analysis. Three-dimensional groundwater flow in Shobasama site in Tono was analyzed using two continuum models and one discontinuous model. The domain of this study covered area of four kilometers in east-west direction and six kilometers in north-south direction. Moreover, for the purpose of evaluating how uncertainties included in modeling of hydrogeological structure and results of groundwater simulation decreased with progress of investigation research, updating and calibration of the models about several modeling techniques of hydrogeological structure and groundwater flow analysis techniques were carried out, based on the information and knowledge which were newly acquired. The acquired knowledge is as follows. As a result of setting parameters and structures in renewal of the models following to the circumstances by last year, there is no big difference to handling between modeling methods. The model calibration is performed by the method of matching numerical simulation with observation, about the pressure response caused by opening and closing of a packer in MIU-2 borehole. Each analysis technique attains reducing of residual sum of squares of observations and results of numerical simulation by adjusting hydrogeological parameters. However, each model adjusts different parameters as water conductivity, effective porosity, specific storage, and anisotropy. When calibrating models, sometimes it is impossible to explain the phenomena only by adjusting parameters. In such case, another investigation may be required to clarify details of hydrogeological structure more. As a result of comparing research from beginning to this year, the following conclusions are obtained about investigation. (1) The transient hydraulic data are effective means in reducing the uncertainty of hydrogeological structure. (2) Effective porosity for calculating pore water velocity of

  17. Synthetic Study on the Geological and Hydrogeological Model around KURT

    International Nuclear Information System (INIS)

    Park, Kyung Woo; Kim, Kyung Su; Koh, Yong Kwon; Choi, Jong Won

    2011-01-01

    To characterize the site specific properties of a study area for high-level radioactive waste disposal research in KAERI, the several geological investigations such as surface geological surveys and borehole drillings were carried out since 1997. Especially, KURT (KAERI Underground Research Tunnel) was constructed to understand the further study of geological environments in 2006. As a result, the first geological model of a study area was constructed by using the results of geological investigation. The objective of this research is to construct a hydrogeological model around KURT area on the basis of the geological model. Hydrogeological data which were obtained from in-situ hydraulic tests in the 9 boreholes were estimated to accomplish the objective. And, the hydrogeological properties of the 4 geological elements in the geological model, which were the subsurface weathering zone, the log angle fracture zone, the fracture zones and the bedrock were suggested. The hydrogeological model suggested in this study will be used as input parameters to carry out the groundwater flow modeling as a next step of the site characterization around KURT area

  18. GIS-based hydrogeological databases and groundwater modelling

    Science.gov (United States)

    Gogu, Radu Constantin; Carabin, Guy; Hallet, Vincent; Peters, Valerie; Dassargues, Alain

    2001-12-01

    Reliability and validity of groundwater analysis strongly depend on the availability of large volumes of high-quality data. Putting all data into a coherent and logical structure supported by a computing environment helps ensure validity and availability and provides a powerful tool for hydrogeological studies. A hydrogeological geographic information system (GIS) database that offers facilities for groundwater-vulnerability analysis and hydrogeological modelling has been designed in Belgium for the Walloon region. Data from five river basins, chosen for their contrasting hydrogeological characteristics, have been included in the database, and a set of applications that have been developed now allow further advances. Interest is growing in the potential for integrating GIS technology and groundwater simulation models. A "loose-coupling" tool was created between the spatial-database scheme and the groundwater numerical model interface GMS (Groundwater Modelling System). Following time and spatial queries, the hydrogeological data stored in the database can be easily used within different groundwater numerical models. Résumé. La validité et la reproductibilité de l'analyse d'un aquifère dépend étroitement de la disponibilité de grandes quantités de données de très bonne qualité. Le fait de mettre toutes les données dans une structure cohérente et logique soutenue par les logiciels nécessaires aide à assurer la validité et la disponibilité et fournit un outil puissant pour les études hydrogéologiques. Une base de données pour un système d'information géographique (SIG) hydrogéologique qui offre toutes les facilités pour l'analyse de la vulnérabilité des eaux souterraines et la modélisation hydrogéologique a été établi en Belgique pour la région Wallonne. Les données de cinq bassins de rivières, choisis pour leurs caractéristiques hydrogéologiques différentes, ont été introduites dans la base de données, et un ensemble d

  19. hydrogeological caracterization and modeling of the aquifer of oued ...

    African Journals Online (AJOL)

    K. Baba-Hamed

    1 janv. 2018 ... Journal of Fundamental and Applied Sciences is licensed under a Creative Commons Attribution-NonCommercial 4.0. International License. Libraries Resource Directory. We are listed under Research Associations category. HYDROGEOLOGICAL CARACTERIZATION AND MODELING OF THE AQUIFER.

  20. Hydrogeological Properties of Geological Elements in Geological Model around KURT

    Energy Technology Data Exchange (ETDEWEB)

    Park, Kyung Woo; Kim, Kyung Soo; Koh, Yong Kwon; Choi, Jong Won [Korea Atomic Energy Institue, Daejeon (Korea, Republic of)

    2012-09-15

    To develop site characterization technologies for a radioactive waste disposal research in KAERI, the geological and hydrogeological investigations have been carried out since 1997. In 2006, the KURT (KAERI Underground Research Tunnel) was constructed to study a solute migration, a microbiology and an engineered barrier system as well as deeply to understand geological environments in in-situ condition. This study is performed as one of the site characterization works around KURT. Several investigations such as a lineament analysis, a borehole/tunnel survey, a geophyscial survey and logging in borehole, were used to construct the geological model. As a result, the geological model is constructed, which includes the lithological model and geo-structural model in this study. Moreover, from the results of the in-situ hydraulic tests, the hydrogeological properties of elements in geological model were evaluated.

  1. Hydrogeological Properties of Geological Elements in Geological Model around KURT

    International Nuclear Information System (INIS)

    Park, Kyung Woo; Kim, Kyung Soo; Koh, Yong Kwon; Choi, Jong Won

    2012-01-01

    To develop site characterization technologies for a radioactive waste disposal research in KAERI, the geological and hydrogeological investigations have been carried out since 1997. In 2006, the KURT (KAERI Underground Research Tunnel) was constructed to study a solute migration, a microbiology and an engineered barrier system as well as deeply to understand geological environments in in-situ condition. This study is performed as one of the site characterization works around KURT. Several investigations such as a lineament analysis, a borehole/tunnel survey, a geophyscial survey and logging in borehole, were used to construct the geological model. As a result, the geological model is constructed, which includes the lithological model and geo-structural model in this study. Moreover, from the results of the in-situ hydraulic tests, the hydrogeological properties of elements in geological model were evaluated.

  2. Development of hydrogeological modelling tools based on NAMMU

    Energy Technology Data Exchange (ETDEWEB)

    Marsic, N. [Kemakta Konsult AB, Stockholm (Sweden); Hartley, L.; Jackson, P.; Poole, M. [AEA Technology, Harwell (United Kingdom); Morvik, A. [Bergen Software Services International AS, Bergen (Norway)

    2001-09-01

    A number of relatively sophisticated hydrogeological models were developed within the SR 97 project to handle issues such as nesting of scales and the effects of salinity. However, these issues and others are considered of significant importance and generality to warrant further development of the hydrogeological methodology. Several such developments based on the NAMMU package are reported here: - Embedded grid: nesting of the regional- and site-scale models within the same numerical model has given greater consistency in the structural model representation and in the flow between scales. Since there is a continuous representation of the regional- and site-scales the modelling of pathways from the repository no longer has to be contained wholly by the site-scale region. This allows greater choice in the size of the site-scale. - Implicit Fracture Zones (IFZ): this method of incorporating the structural model is very efficient and allows changes to either the mesh or fracture zones to be implemented quickly. It also supports great flexibility in the properties of the structures and rock mass. - Stochastic fractures: new functionality has been added to IFZ to allow arbitrary combinations of stochastic or deterministic fracture zones with the rock-mass. Whether a fracture zone is modelled deterministically or stochastically its statistical properties can be defined independently. - Stochastic modelling: efficient methods for Monte-Carlo simulation of stochastic permeability fields have been implemented and tested on SKB's computers. - Visualisation: the visualisation tool Avizier for NAMMU has been enhanced such that it is efficient for checking models and presentation. - PROPER interface: NAMMU outputs pathlines in PROPER format so that it can be included in PA workflow. The developed methods are illustrated by application to stochastic nested modelling of the Beberg site using data from SR 97. The model properties were in accordance with the regional- and site

  3. Development of hydrogeological modelling tools based on NAMMU

    International Nuclear Information System (INIS)

    Marsic, N.; Hartley, L.; Jackson, P.; Poole, M.; Morvik, A.

    2001-09-01

    A number of relatively sophisticated hydrogeological models were developed within the SR 97 project to handle issues such as nesting of scales and the effects of salinity. However, these issues and others are considered of significant importance and generality to warrant further development of the hydrogeological methodology. Several such developments based on the NAMMU package are reported here: - Embedded grid: nesting of the regional- and site-scale models within the same numerical model has given greater consistency in the structural model representation and in the flow between scales. Since there is a continuous representation of the regional- and site-scales the modelling of pathways from the repository no longer has to be contained wholly by the site-scale region. This allows greater choice in the size of the site-scale. - Implicit Fracture Zones (IFZ): this method of incorporating the structural model is very efficient and allows changes to either the mesh or fracture zones to be implemented quickly. It also supports great flexibility in the properties of the structures and rock mass. - Stochastic fractures: new functionality has been added to IFZ to allow arbitrary combinations of stochastic or deterministic fracture zones with the rock-mass. Whether a fracture zone is modelled deterministically or stochastically its statistical properties can be defined independently. - Stochastic modelling: efficient methods for Monte-Carlo simulation of stochastic permeability fields have been implemented and tested on SKB's computers. - Visualisation: the visualisation tool Avizier for NAMMU has been enhanced such that it is efficient for checking models and presentation. - PROPER interface: NAMMU outputs pathlines in PROPER format so that it can be included in PA workflow. The developed methods are illustrated by application to stochastic nested modelling of the Beberg site using data from SR 97. The model properties were in accordance with the regional- and site

  4. Hydrogeological characterization, modelling and monitoring of the site of Canada's Underground Research Laboratory

    International Nuclear Information System (INIS)

    Davison, C.C.; Guvanasen, V.

    1985-01-01

    Atomic Energy of Canada Limited (AECL) is constructing an Underground Research Laboratory (URL) to a depth of 250 m in a previously undisturbed granitic pluton located near Lac du Bonnet, Manitoba, as one of the major research projects within the Canadian Nuclear Fuel Waste Management Program. This paper discusses the hydrogeological characterization of the URL site, the modelling approach used to represent this information, the hydrogeological monitoring system installed to monitor the actual drawdown conditions that develop in response to the excavation, and the procedures employed to calibrate the numerical model. Comparisons between the drawdown predictions made by the model prior to any excavation and the actual drawdowns that have been measured since shaft excavation began in May 1984 are also discussed

  5. Scale problems in assessment of hydrogeological parameters of groundwater flow models

    Science.gov (United States)

    Nawalany, Marek; Sinicyn, Grzegorz

    2015-09-01

    An overview is presented of scale problems in groundwater flow, with emphasis on upscaling of hydraulic conductivity, being a brief summary of the conventional upscaling approach with some attention paid to recently emerged approaches. The focus is on essential aspects which may be an advantage in comparison to the occasionally extremely extensive summaries presented in the literature. In the present paper the concept of scale is introduced as an indispensable part of system analysis applied to hydrogeology. The concept is illustrated with a simple hydrogeological system for which definitions of four major ingredients of scale are presented: (i) spatial extent and geometry of hydrogeological system, (ii) spatial continuity and granularity of both natural and man-made objects within the system, (iii) duration of the system and (iv) continuity/granularity of natural and man-related variables of groundwater flow system. Scales used in hydrogeology are categorised into five classes: micro-scale - scale of pores, meso-scale - scale of laboratory sample, macro-scale - scale of typical blocks in numerical models of groundwater flow, local-scale - scale of an aquifer/aquitard and regional-scale - scale of series of aquifers and aquitards. Variables, parameters and groundwater flow equations for the three lowest scales, i.e., pore-scale, sample-scale and (numerical) block-scale, are discussed in detail, with the aim to justify physically deterministic procedures of upscaling from finer to coarser scales (stochastic issues of upscaling are not discussed here). Since the procedure of transition from sample-scale to block-scale is physically well based, it is a good candidate for upscaling block-scale models to local-scale models and likewise for upscaling local-scale models to regional-scale models. Also the latest results in downscaling from block-scale to sample scale are briefly referred to.

  6. Scale problems in assessment of hydrogeological parameters of groundwater flow models

    Directory of Open Access Journals (Sweden)

    Nawalany Marek

    2015-09-01

    Full Text Available An overview is presented of scale problems in groundwater flow, with emphasis on upscaling of hydraulic conductivity, being a brief summary of the conventional upscaling approach with some attention paid to recently emerged approaches. The focus is on essential aspects which may be an advantage in comparison to the occasionally extremely extensive summaries presented in the literature. In the present paper the concept of scale is introduced as an indispensable part of system analysis applied to hydrogeology. The concept is illustrated with a simple hydrogeological system for which definitions of four major ingredients of scale are presented: (i spatial extent and geometry of hydrogeological system, (ii spatial continuity and granularity of both natural and man-made objects within the system, (iii duration of the system and (iv continuity/granularity of natural and man-related variables of groundwater flow system. Scales used in hydrogeology are categorised into five classes: micro-scale – scale of pores, meso-scale – scale of laboratory sample, macro-scale – scale of typical blocks in numerical models of groundwater flow, local-scale – scale of an aquifer/aquitard and regional-scale – scale of series of aquifers and aquitards. Variables, parameters and groundwater flow equations for the three lowest scales, i.e., pore-scale, sample-scale and (numerical block-scale, are discussed in detail, with the aim to justify physically deterministic procedures of upscaling from finer to coarser scales (stochastic issues of upscaling are not discussed here. Since the procedure of transition from sample-scale to block-scale is physically well based, it is a good candidate for upscaling block-scale models to local-scale models and likewise for upscaling local-scale models to regional-scale models. Also the latest results in downscaling from block-scale to sample scale are briefly referred to.

  7. Evaluate the accuracy of the numerical solution of hydrogeological problems of mass transfer

    Directory of Open Access Journals (Sweden)

    Yevhrashkina G.P.

    2014-12-01

    Full Text Available In the hydrogeological task on quantifying pollution of aquifers the error are starting add up with moment organization of regime observation network as a source of information on the pollution of groundwater in order to evaluate migration options for future prognosis calculations. Optimum element regime observation network should consist of three drill holes on the groundwater flow at equal distances from one another and transversely to the flow of the three drill holes, and at equal distances. If the target of observation drill holes coincides with the stream line on which will then be decided by direct migration task, the error will be minimal. The theoretical basis and results of numerical experiments to assess the accuracy of direct predictive tasks planned migration of groundwater in the area of full water saturation. For the vadose zone, we consider problems of vertical salt transport moisture. All studies were performed by comparing the results of fundamental and approximate solutions in a wide range of characteristics of the processes, which are discussed in relation to ecological and hydrogeological conditions of mining regions on the example of the Western Donbass.

  8. Hydrogeologic Modeling at the Sylvania Corning FUSRAP Site - 13419

    Energy Technology Data Exchange (ETDEWEB)

    Ewy, Ann [U.S. Army Corps of Engineers, Kansas City District (United States); Heim, Kenneth J. [U.S. Army Corps of Engineers, New England District (United States); McGonigal, Sean T.; Talimcioglu, Nazmi M. [The Louis Berger Group, Inc. (United States)

    2013-07-01

    A comparative groundwater hydrogeologic modeling analysis is presented herein to simulate potential contaminant migration pathways in a sole source aquifer in Nassau County, Long Island, New York. The source of contamination is related to historical operations at the Sylvania Corning Plant ('Site'), a 9.49- acre facility located at 70, 100 and 140 Cantiague Rock Road, Town of Oyster Bay in the westernmost portion of Hicksville, Long Island. The Site had historically been utilized as a nuclear materials manufacturing facility (e.g., cores, slug, and fuel elements) for reactors used in both research and electric power generation in early 1950's until late 1960's. The Site is contaminated with various volatile organic and inorganic compounds, as well as radionuclides. The major contaminants of concern at the Site are tetrachloroethene (PCE), trichloroethene (TCE), nickel, uranium, and thorium. These compounds are present in soil and groundwater underlying the Site and have migrated off-site. The Site is currently being investigated as part of the Formerly Utilized Sites Remedial Action Program (FUSRAP). The main objective of the current study is to simulate the complex hydrogeologic features in the region, such as numerous current and historic production well fields; large, localized recharge basins; and, multiple aquifers, and to assess potential contaminant migration pathways originating from the Site. For this purpose, the focus of attention was given to the underlying Magothy formation, which has been impacted by the contaminants of concern. This aquifer provides more than 90% of potable water supply in the region. Nassau and Suffolk Counties jointly developed a three-dimensional regional groundwater flow model to help understand the factors affecting groundwater flow regime in the region, to determine adequate water supply for public consumption, to investigate salt water intrusion in localized areas, to evaluate the impacts of regional

  9. On the combination of isotope hydrogeology with regional flow and transport modelling

    International Nuclear Information System (INIS)

    Barmen, G.A.

    1992-01-01

    Many different methods and tools can be used when trying to improve the information basis on which decisions are made for maintaining a quantitatively and qualitatively safe, long-term use of groundwater resources. In this thesis, classical hydrogeological examinations, hydrochemical investigations, environmental isotope studies, computerized groundwater flow modelling and radioisotope transport modelling have been applied to the large system of reservoirs in the sedimentary deposits of southwestern Scania, Sweden. The stable isotopes 2 H, 18 O and 13 C and the radioactive 3 H and 14 C have been measured and the results obtained can improve the estimations of the periods of recharge and the average circulation times of the groundwater reservoirs studied. A groundwater flow model based on finite difference techniques and a continuum approach has been modified by data from traditional hydrogeological studies. The computer code, NEWSAM, has been used to simulate steady-state and transient isotope transport in the area studied, taking into account advective transport with radioactive decay. The interacting groundwater resevoirs studied have been represented by a three-dimensional system of grids in the numerical model. A major merit of this combination of isotope hydrogeology and regional flow and transport modelling is that the isotope transport simulations help to demonstrate where zones particularly vulnerable to pollution are situated. These locations are chiefly the results of the hydrogeological characteristics traditionally examined, but they are revealed by means of the transport model. Subsequent, more detailed investigations can then be focussed primarily on these vulnerable zones. High contents of radioisotopes in the main aquifer of southwestern Scania may indicate that groundwater withdrawals have stimulated recharge from shallow aquifers and surface waters and that the risk of pollution has increased. (196 refs.) (au)

  10. Development of hydrogeological modelling approaches for assessment of consequences of hazardous accidents at nuclear power plants

    International Nuclear Information System (INIS)

    Rumynin, V.G.; Mironenko, V.A.; Konosavsky, P.K.; Pereverzeva, S.A.

    1994-07-01

    This paper introduces some modeling approaches for predicting the influence of hazardous accidents at nuclear reactors on groundwater quality. Possible pathways for radioactive releases from nuclear power plants were considered to conceptualize boundary conditions for solving the subsurface radionuclides transport problems. Some approaches to incorporate physical-and-chemical interactions into transport simulators have been developed. The hydrogeological forecasts were based on numerical and semi-analytical scale-dependent models. They have been applied to assess the possible impact of the nuclear power plants designed in Russia on groundwater reservoirs

  11. Modelling of future hydrogeological conditions at SFR

    International Nuclear Information System (INIS)

    Holmen, L.G.; Stigsson, M.

    2001-03-01

    The purpose is to estimate the future groundwater movements at the SFR repository and to produce input to the quantitative safety assessment of the SFR. The future flow pattern of the groundwater is of interest, since components of the waste emplaced in a closed and abandoned repository will dissolve in the groundwater and be transported by the groundwater to the ground surface. The study is based on a system analysis approach. Three-dimensional models were devised of the studied domain. The models include the repository tunnels and the surrounding rock mass with fracture zones. The formal models used for simulation of the groundwater flow are three-dimensional mathematical descriptions of the studied hydraulic system. The studied domain is represented on four scales - regional, local, semi local and detailed - forming four models with different resolutions: regional, local, semi local and detailed models. The local and detailed models include a detailed description of the tunnel system at SFR and of surrounding rock mass and fracture zones. In addition, the detailed model includes description of the different structures that take place inside the deposition tunnels. At the area studied, the shoreline will retreat due to the shore level displacement; this process is included in the models. The studied period starts at 2000 AD and continues until a steady state like situation is reached for the surroundings of the SFR at ca 6000 AD. The models predict that as long as the sea covers the ground above the SFR, the regional groundwater flow as well as the flow in the deposition tunnels are small. However, due to the shore level displacement the shoreline (the sea) will retreat. Because of the retreating shoreline, the general direction of the groundwater flow at SFR will change, from vertical upward to a more horizontal flow; the size of the groundwater flow will be increased as well. The present layout of the SFR includes five deposition tunnels: SILO, BMA, BLA, BTF1

  12. Hydrogeologic model for the old Hanford townsite

    International Nuclear Information System (INIS)

    MacDonald, Q.; Csun, C.

    1994-01-01

    The Hanford Site in southeastern Washington state produced the country's first plutonium during WW II, and production continued through the end of the cold war. This plutonium production generated significant volumes of chemical and radioactive wastes, some of which were discharged directly to the local sediments as wastewater. Artifical recharge is still the dominating influence on the uppermost and unconfined aquifer over much of the Hanford site. Groundwater from a portion of this aquifer, which is in excess of drinking water standards for tritium, discharges to the Columbia River in the vicinity of the old Hanford townsite. The Hanford site lies within the Pasco basin, which is a structural basin in the Columbia Plateau. Columbia River basalt is overlain by the fluvial and lacustrian Ringold formation. The Ringold is unconformably overlain by the informal Hanford formation. Relatively impermeable basalt outcrops and subcrops along a northwest-southeast-trending anticline across the study area. Hanford sediments include both fluvial and glacial flood deposits lying on an irregular surface of basalt and sedimentary rocks. The coarser flood deposits have very high hydraulic conductivity and probably are the most important conduit for contaminant transport within the aquifer. A finite element model (CFEST-SC) is being used to study the effect of changing river stage on baseflow to the Columbia River near the old Hanford townsite. A steady-state version of the model produces calculated head within 1 m of observed values. Transient flow and solute transport results are expected to help further define the relationship between the contaminated aquifer and the Columbia River

  13. Coupled geochemical/hydrogeological modelling to assess the origin of salinity at the Tono area (Japan)

    International Nuclear Information System (INIS)

    Guimera, Jordi; Ruiz, Eduardo; Luna, Miguel; Arcos, David; Jordana, Salvador; Saegusa, Hiromitsu

    2005-01-01

    Numerical models are powerful tools for the characterization of groundwater flow, especially when integrating geochemical and hydrogeological data. This paper describes modeling exercises performed in the area surrounding the Mizunami Underground Research Laboratory (MIU) Construction Site in central Japan. A particular issue being investigated at the MIU Site is the presence of saline water detected at depth in certain boreholes. The main objective of this study is to develop conceptual physical models for the origin of this salinity and to test these conceptual models using numerical modeling techniques. One scenario being investigated is that the saline fluids represent residual Miocene age seawater which has been slightly altered by water-rock interactions. It is likely that during Miocene times, seawater inundated the Tono area. This hypothesis is partially supported by carbon and oxygen isotopic data of the calcite fracture filling materials. (author)

  14. On the significance of contaminant plume-scale and dose-response models in defining hydrogeological characterization needs

    Science.gov (United States)

    de Barros, F.; Rubin, Y.; Maxwell, R.; Bai, H.

    2007-12-01

    Defining rational and effective hydrogeological data acquisition strategies is of crucial importance since financial resources available for such efforts are always limited. Usually such strategies are developed with the goal of reducing uncertainty, but less often they are developed in the context of the impacts of uncertainty. This paper presents an approach for determining site characterization needs based on human health risk factors. The main challenge is in striking a balance between improved definition of hydrogeological, behavioral and physiological parameters. Striking this balance can provide clear guidance on setting priorities for data acquisition and for better estimating adverse health effects in humans. This paper addresses this challenge through theoretical developments and numerical testing. We will report on a wide range of factors that affect the site characterization needs including contaminant plume's dimensions, travel distances and other length scales that characterize the transport problem, as well as health risk models. We introduce a new graphical tool that allows one to investigate the relative impact of hydrogeological and physiological parameters in risk. Results show that the impact of uncertainty reduction in the risk-related parameters decreases with increasing distances from the contaminant source. Also, results indicate that human health risk becomes less sensitive to hydrogeological measurements when dealing with ergodic plumes. This indicates that under ergodic conditions, uncertainty reduction in human health risk may benefit from better understanding of the physiological component as opposed to a detailed hydrogeological characterization

  15. Modelling of the site scale hydrogeological situation at Beberg using NAMMU

    International Nuclear Information System (INIS)

    Marsic, N.; Gylling, B.; Grundfelt, B.; Hartley, L.

    2000-02-01

    The purpose of the present study is to perform modelling of the site scale hydrogeological situation at Beberg using the finite element code NAMMU and compare the results with those from HYDRASTAR reported in SR 97. NAMMU was used in the large scale regional hydrogeological modelling at Beberg. The hypothetical repository layout at Beberg is based on geological data from the Finnsjoen site. Four model variants were created in this study. Two variants were compared with the deterministic freshwater case in the HYDRASTAR modelling. The other two variants were created to study the effect of a regionally distributed permeability anisotropy and variable density groundwater on the groundwater flow pattern. These processes are not considered in HYDRASTAR. The NAMMU results, including the pathline patterns, agree with those from the HYDRASTAR modelling. The effect of anisotropy and saline groundwater is found significant for the pathlines. The difference in canister flux between the NAMMU and the HYDRASTAR models is small, while the difference in travel time is more significant. The discrepancies between the results from the NAMMU and the HYDRASTAR simulations can be ascribed to the different numerical discretisation, i.e. different representation of the permeability, and the different pathline algorithms used in the two models

  16. Alligator Rivers Analogue project. Hydrogeological modelling. Final Report - Volume 6

    International Nuclear Information System (INIS)

    Townley, L.R.; Trefry, M.G.; Barr, A.D.; Braumiller, S.

    1992-01-01

    This volume describes hydrogeological modelling carried out as part of the Alligator Rivers Analogue Project. Hydrogeology has played a key integrating role in the Project, largely because water movement is believed to have controlled the evolution of the Koongarra uranium Orebody and therefore affects field observations of all types at all scales. Aquifer testing described uses the concept of transmissivity in its interpretation of aquifer response to pumping. The concept of an aquifer, a layer transmitting significant quantities of water in a mainly horizontal direction, seems hard to accept in an environment as heterogeneous as that at Koongarra. But modelling of aquifers both in one dimension and two dimensionally in plan has contributed significantly to our understanding of the site. A one-dimensional model with three layers (often described as a quasi two dimensional model) was applied to flow between the Fault and Koongarra Creek. Being a transient model, this model was able to show that reverse flows can indeed occur back towards the Fault, but only if there is distributed recharge over the orebody as well as a mechanism for the Fault, or a region near the Fault, to remove water from the simulated cross-section. The model also showed clearly that the response of the three-layered system, consisting of a highly weathered zone, a fractured transmissive zone and a less conductive lower schist zone, is governed mainly by the transmissivity and storage coefficient of the middle layer. The storage coefficient of the higher layer has little effect. A two-dimensional model in plan used a description of anisotropy to show that reverse flows can also occur even without a conducting Fault. Modelling of a three-dimensional region using discrete fractures showed that it is certainly possible to simulate systems like that observed at Koongarra, but that large amounts of data are probably needed to obtain realistic descriptions of the fracture networks. Inverse modelling

  17. Alligator Rivers Analogue project. Hydrogeological modelling. Final Report - Volume 6

    Energy Technology Data Exchange (ETDEWEB)

    Townley, L R; Trefry, M G; Barr, A D [CSIRO Div of Water Resources, PO Wembley, WA (Australia); Braumiller, S [Univ of Arizona, Tucson, AZ (United States). Dept of Hydrology and Water Resources; Kawanishi, M [Central Research Institute of Electric Power Industry, Abiko-Shi, Chiba-Ken (Japan); and others

    1993-12-31

    This volume describes hydrogeological modelling carried out as part of the Alligator Rivers Analogue Project. Hydrogeology has played a key integrating role in the Project, largely because water movement is believed to have controlled the evolution of the Koongarra uranium Orebody and therefore affects field observations of all types at all scales. Aquifer testing described uses the concept of transmissivity in its interpretation of aquifer response to pumping. The concept of an aquifer, a layer transmitting significant quantities of water in a mainly horizontal direction, seems hard to accept in an environment as heterogeneous as that at Koongarra. But modelling of aquifers both in one dimension and two dimensionally in plan has contributed significantly to our understanding of the site. A one-dimensional model with three layers (often described as a quasi two dimensional model) was applied to flow between the Fault and Koongarra Creek. Being a transient model, this model was able to show that reverse flows can indeed occur back towards the Fault, but only if there is distributed recharge over the orebody as well as a mechanism for the Fault, or a region near the Fault, to remove water from the simulated cross-section. The model also showed clearly that the response of the three-layered system, consisting of a highly weathered zone, a fractured transmissive zone and a less conductive lower schist zone, is governed mainly by the transmissivity and storage coefficient of the middle layer. The storage coefficient of the higher layer has little effect. A two-dimensional model in plan used a description of anisotropy to show that reverse flows can also occur even without a conducting Fault. Modelling of a three-dimensional region using discrete fractures showed that it is certainly possible to simulate systems like that observed at Koongarra, but that large amounts of data are probably needed to obtain realistic descriptions of the fracture networks. Inverse modelling

  18. Hydrogeological framework, numerical simulation of groundwater flow, and effects of projected water use and drought for the Beaver-North Canadian River alluvial aquifer, northwestern Oklahoma

    Science.gov (United States)

    Ryter, Derek W.; Correll, Jessica S.

    2016-01-14

    This report describes a study of the hydrology, hydrogeological framework, numerical groundwater-flow models, and results of simulations of the effects of water use and drought for the Beaver-North Canadian River alluvial aquifer, northwestern Oklahoma. The purpose of the study was to provide analyses, including estimating equal-proportionate-share (EPS) groundwater-pumping rates and the effects of projected water use and droughts, pertinent to water management of the Beaver-North Canadian River alluvial aquifer for the Oklahoma Water Resources Board.

  19. Development of Numerical Grids for UZ Flow and Transport Modeling

    International Nuclear Information System (INIS)

    Hinds, J.

    2001-01-01

    This Analysis/Model Report (AMR) describes the methods used to develop numerical grids of the unsaturated hydrogeologic system beneath Yucca Mountain. Numerical grid generation is an integral part of the development of a complex, three-dimensional (3-D) model, such as the Unsaturated-Zone Flow and Transport Model (UZ Model) of Yucca Mountain. The resulting numerical grids, developed using current geologic, hydrogeologic, and mineralogic data, provide the necessary framework to: (1) develop calibrated hydrogeologic property sets and flow fields, (2) test conceptual hypotheses of flow and transport, and (3) predict flow and transport behavior under a variety of climatic and thermal loading conditions. Revision 00 of the work described herein follows the planning and work direction outlined in the ''Development of Numerical Grids for UZ Flow and Transport Modeling'' (CRWMS M and O 1999c). The technical scope, content, and management of ICN 01 of this AMR is currently controlled by the planning document, ''Technical Work Plan for Unsaturated Zone (UZ) Flow and Transport Process Model Report'' (BSC 2001a). The scope for the TBV resolution actions in this ICN is described in the ''Technical Work Plan for: Integrated Management of Technical Product Input Department'' (BSC 2001 b, Addendum B, Section 4.1). The steps involved in numerical grid development include: (1) defining the location of important calibration features, (2) determining model grid layers and fault geometry based on the Geologic Framework Model (GFM), the Integrated Site Model (ISM), and definition of hydrogeologic units (HGUs), (3) analyzing and extracting GFM and ISM data pertaining to layer contacts and property distributions, (4) discretizing and refining the two-dimensional (2-D), plan-view numerical grid, (5) generating the 3-D grid with finer resolution at the repository horizon and within the Calico Hills nonwelded (CHn) hydrogeologic unit, and (6) formulating the dual-permeability mesh. The

  20. Methodology for deriving hydrogeological input parameters for safety-analysis models - application to fractured crystalline rocks of Northern Switzerland

    International Nuclear Information System (INIS)

    Vomvoris, S.; Andrews, R.W.; Lanyon, G.W.; Voborny, O.; Wilson, W.

    1996-04-01

    Switzerland is one of many nations with nuclear power that is seeking to identify rock types and locations that would be suitable for the underground disposal of nuclear waste. A common challenge among these programs is to provide engineering designers and safety analysts with a reasonably representative hydrogeological input dataset that synthesizes the relevant information from direct field observations as well as inferences and model results derived from those observations. Needed are estimates of the volumetric flux through a volume of rock and the distribution of that flux into discrete pathways between the repository zones and the biosphere. These fluxes are not directly measurable but must be derived based on understandings of the range of plausible hydrogeologic conditions expected at the location investigated. The methodology described in this report utilizes conceptual and numerical models at various scales to derive the input dataset. The methodology incorporates an innovative approach, called the geometric approach, in which field observations and their associated uncertainty, together with a conceptual representation of those features that most significantly affect the groundwater flow regime, were rigorously applied to generate alternative possible realizations of hydrogeologic features in the geosphere. In this approach, the ranges in the output values directly reflect uncertainties in the input values. As a demonstration, the methodology is applied to the derivation of the hydrogeological dataset for the crystalline basement of Northern Switzerland. (author) figs., tabs., refs

  1. Study on the methodology for hydrogeological site descriptive modelling by discrete fracture networks

    International Nuclear Information System (INIS)

    Tanaka, Tatsuya; Ando, Kenichi; Hashimoto, Shuuji; Saegusa, Hiromitsu; Takeuchi, Shinji; Amano, Kenji

    2007-01-01

    This study aims to establish comprehensive techniques for site descriptive modelling considering the hydraulic heterogeneity due to the Water Conducting Features in fractured rocks. The WCFs was defined by the interpretation and integration of geological and hydrogeological data obtained from the deep borehole investigation campaign in the Mizunami URL project and Regional Hydrogeological Study. As a result of surface based investigation phase, the block-scale hydrogeological descriptive model was generated using hydraulic discrete fracture networks. Uncertainties and remaining issues associated with the assumption in interpreting the data and its modelling were addressed in a systematic way. (author)

  2. Preliminary simulation model to determine ground-water flow and ages within the Palo Duro Basin hydrogeologic province

    International Nuclear Information System (INIS)

    Atwood, H.; Picking, L.

    1986-01-01

    Ground-water flow through the Palo Duro and Tucumcari Basins is simulated by developing a hydrogeolgic profile and applying a cross-sectional, finite-element, numerical model to the profile. The profile is 350 miles long and 2 miles deep and extends from east-central New Mexico to the Texas-Oklahoma border. It is comprised of hydrogeologic units that are identified from geophysical well logs, sample logs, and core descriptions. A hydrogeologic unit as used in this profile is a physically continuous rock sequence with hydrologic properties that are relatively consistent throughout and distinct from surrounding units. The resulting hydrogeologic profile, with the exception of the Ogallala Formation and the Dockum Group, is discretized into a 6000-element mesh and a 22,000-element mesh. Permeability values assigned to hydrogeologic units were, in part, calculated from drill stem tests conducted throughout the Palo Duro Basin. Ground-water age and travel paths are determined by applying Darcy's equation to selected flow lines. The 170 million-year age determined from ground-water at points within the Wolfcamp Series compares favorably with the geochemical data for this region. An age of 188 million years is determined for the Pennsylvanian granite wash

  3. A Bayesian Markov geostatistical model for estimation of hydrogeological properties

    International Nuclear Information System (INIS)

    Rosen, L.; Gustafson, G.

    1996-01-01

    A geostatistical methodology based on Markov-chain analysis and Bayesian statistics was developed for probability estimations of hydrogeological and geological properties in the siting process of a nuclear waste repository. The probability estimates have practical use in decision-making on issues such as siting, investigation programs, and construction design. The methodology is nonparametric which makes it possible to handle information that does not exhibit standard statistical distributions, as is often the case for classified information. Data do not need to meet the requirements on additivity and normality as with the geostatistical methods based on regionalized variable theory, e.g., kriging. The methodology also has a formal way for incorporating professional judgments through the use of Bayesian statistics, which allows for updating of prior estimates to posterior probabilities each time new information becomes available. A Bayesian Markov Geostatistical Model (BayMar) software was developed for implementation of the methodology in two and three dimensions. This paper gives (1) a theoretical description of the Bayesian Markov Geostatistical Model; (2) a short description of the BayMar software; and (3) an example of application of the model for estimating the suitability for repository establishment with respect to the three parameters of lithology, hydraulic conductivity, and rock quality designation index (RQD) at 400--500 meters below ground surface in an area around the Aespoe Hard Rock Laboratory in southeastern Sweden

  4. Large scale hydrogeological modelling of a low-lying complex coastal aquifer system

    DEFF Research Database (Denmark)

    Meyer, Rena

    2018-01-01

    intrusion. In this thesis a new methodological approach was developed to combine 3D numerical groundwater modelling with a detailed geological description and hydrological, geochemical and geophysical data. It was applied to a regional scale saltwater intrusion in order to analyse and quantify...... the groundwater flow dynamics, identify the driving mechanisms that formed the saltwater intrusion to its present extent and to predict its progression in the future. The study area is located in the transboundary region between Southern Denmark and Northern Germany, adjacent to the Wadden Sea. Here, a large-scale...... parametrization schemes that accommodate hydrogeological heterogeneities. Subsequently, density-dependent flow and transport modelling of multiple salt sources was successfully applied to simulate the formation of the saltwater intrusion during the last 4200 years, accounting for historic changes in the hydraulic...

  5. Hydrogeological measurements and modelling of the Down Ampney Fault Research site

    International Nuclear Information System (INIS)

    Brightman, M.A.; Sen, M.A.; Abbott, M.A.W.

    1991-01-01

    The British Geological Survey, in cooperation with ISMES of Italy, is carrying out a research programme into the properties of faults cutting clay formations. The programme has two major aims; firstly, to develop geophysical techniques to locate and measure the geophysical properties of a fault in clay; secondly, to measure the hydrogeological properties of the fault and its effect on the groundwater flow pattern through a sequence of clays and aquifers. Analysis of pulse tests performed in the clays at the Down Ampney Research site gave values of hydraulic conductivity ranging from 5 x 10 -12 to 2 x 10 -8 ms -1 . Numerical modelling of the effects of groundwater abstraction from nearby wells on the site was performed using the finite element code FEMWATER. The results are discussed. (Author)

  6. Numerical Transducer Modeling

    DEFF Research Database (Denmark)

    Henriquez, Vicente Cutanda

    This thesis describes the development of a numerical model of the propagation of sound waves in fluids with viscous and thermal losses, with application to the simulation of acoustic transducers, in particular condenser microphones for measurement. The theoretical basis is presented, numerical...... manipulations are developed to satisfy the more complicated boundary conditions, and a model of a condenser microphone with a coupled membrane is developed. The model is tested against measurements of ¼ inch condenser microphones and analytical calculations. A detailed discussion of the results is given....

  7. Impact of model complexity and multi-scale data integration on the estimation of hydrogeological parameters in a dual-porosity aquifer

    Science.gov (United States)

    Tamayo-Mas, Elena; Bianchi, Marco; Mansour, Majdi

    2018-03-01

    This study investigates the impact of model complexity and multi-scale prior hydrogeological data on the interpretation of pumping test data in a dual-porosity aquifer (the Chalk aquifer in England, UK). In order to characterize the hydrogeological properties, different approaches ranging from a traditional analytical solution (Theis approach) to more sophisticated numerical models with automatically calibrated input parameters are applied. Comparisons of results from the different approaches show that neither traditional analytical solutions nor a numerical model assuming a homogenous and isotropic aquifer can adequately explain the observed drawdowns. A better reproduction of the observed drawdowns in all seven monitoring locations is instead achieved when medium and local-scale prior information about the vertical hydraulic conductivity (K) distribution is used to constrain the model calibration process. In particular, the integration of medium-scale vertical K variations based on flowmeter measurements lead to an improvement in the goodness-of-fit of the simulated drawdowns of about 30%. Further improvements (up to 70%) were observed when a simple upscaling approach was used to integrate small-scale K data to constrain the automatic calibration process of the numerical model. Although the analysis focuses on a specific case study, these results provide insights about the representativeness of the estimates of hydrogeological properties based on different interpretations of pumping test data, and promote the integration of multi-scale data for the characterization of heterogeneous aquifers in complex hydrogeological settings.

  8. Three-dimensional hydrogeologic framework model of the Rio Grande transboundary region of New Mexico and Texas, USA, and northern Chihuahua, Mexico

    Science.gov (United States)

    Sweetkind, Donald S.

    2017-09-08

    As part of a U.S. Geological Survey study in cooperation with the Bureau of Reclamation, a digital three-dimensional hydrogeologic framework model was constructed for the Rio Grande transboundary region of New Mexico and Texas, USA, and northern Chihuahua, Mexico. This model was constructed to define the aquifer system geometry and subsurface lithologic characteristics and distribution for use in a regional numerical hydrologic model. The model includes five hydrostratigraphic units: river channel alluvium, three informal subdivisions of Santa Fe Group basin fill, and an undivided pre-Santa Fe Group bedrock unit. Model input data were compiled from published cross sections, well data, structure contour maps, selected geophysical data, and contiguous compilations of surficial geology and structural features in the study area. These data were used to construct faulted surfaces that represent the upper and lower subsurface hydrostratigraphic unit boundaries. The digital three-dimensional hydrogeologic framework model is constructed through combining faults, the elevation of the tops of each hydrostratigraphic unit, and boundary lines depicting the subsurface extent of each hydrostratigraphic unit. The framework also compiles a digital representation of the distribution of sedimentary facies within each hydrostratigraphic unit. The digital three-dimensional hydrogeologic model reproduces with reasonable accuracy the previously published subsurface hydrogeologic conceptualization of the aquifer system and represents the large-scale geometry of the subsurface aquifers. The model is at a scale and resolution appropriate for use as the foundation for a numerical hydrologic model of the study area.

  9. Preparatory hydrogeological calculations for site scale models of Aberg, Beberg and Ceberg

    International Nuclear Information System (INIS)

    Gylling, B.; Lindgren, M.; Widen, H.

    1999-03-01

    The purpose of the study is to evaluate the basis for site scale models of the three sites Aberg, Beberg and Ceberg in terms of: extent and position of site scale model domains; numerical implementation of geologic structural model; systematic review of structural data and control of compatibility in data sets. Some of the hydrogeological features of each site are briefly described. A summary of the results from the regional modelling exercises for Aberg, Beberg and Ceberg is given. The results from the regional models may be used as a base for determining the location and size of the site scale models and provide such models with boundary conditions. Results from the regional models may also indicate suitable locations for repositories. The resulting locations and sizes for site scale models are presented in figures. There are also figures showing that the structural models interpreted by HYDRASTAR do not conflict with the repository tunnels. It has in addition been verified with TRAZON, a modified version of HYDRASTAR for checking starting positions, revealing conflicts between starting positions and fractures zones if present

  10. An integrated model for simulating nitrogen trading in an agricultural catchment with complex hydrogeology.

    Science.gov (United States)

    Cox, T J; Rutherford, J C; Kerr, S C; Smeaton, D C; Palliser, C C

    2013-09-30

    Nitrogen loads to several New Zealand lakes are dominated by nonpoint runoff from pastoral farmland which adversely affects lake water quality. A 'cap and trade' scheme is being considered to help meet targets set for nitrogen loads to Lake Rotorua, and a numerical model, NTRADER, has been developed to simulate and compare alternative schemes. NTRADER models both the geophysics of nitrogen generation and transport, including groundwater lag times, and the economics of 'cap and trade' schemes. It integrates the output from several existing models, including a farm-scale nitrogen leaching and abatement model, a farm-scale management economic model, and a catchment-scale nitrogen transport model. This paper details modeling methods and compares possible trading program design features for the Lake Rotorua catchment. Model simulations demonstrate how a cap and trade program could be used to effectively achieve challenging environmental goals in the targeted catchment. However, results also show that, due to complex hydrogeology, satisfactory environmental outcomes may be not achieved unless groundwater lag times are incorporated into the regulatory scheme. One way to do this, as demonstrated here, would be to explicitly include lag times in the cap and trade program. The utility of the model is further demonstrated by quantifying relative differences in abatement costs across potential regulatory schemes. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Development of numerical Grids for UZ Flow and Transport Modeling

    International Nuclear Information System (INIS)

    P. Dobson

    2004-01-01

    This report describes the methods used to develop numerical grids of the unsaturated hydrogeologic system beneath Yucca Mountain, Nevada. Numerical grid generation is an integral part of the development of the unsaturated zone (UZ) flow and transport model, a complex, three-dimensional (3-D) model of Yucca Mountain. This revision contains changes made to improve the clarity of the description of grid generation. The numerical grids, developed using current geologic, hydrogeologic, and mineralogic data, provide the necessary framework to: (1) develop calibrated hydrogeologic property sets and flow fields, (2) test conceptual hypotheses of flow and transport, and (3) predict flow and transport behavior under a variety of climatic and thermal-loading conditions. The technical scope, content, and management for the current revision of this report are described in the planning document ''Technical Work Plan for: Unsaturated Zone Flow Analysis and Model Report Integration'' (BSC 2004 [DIRS 169654], Section 2). Grids generated and documented in this report supersede those documented in Revision 00 of this report, ''Development of Numerical Grids for UZ Flow and Transport Modeling'' (BSC 2001 [DIRS 159356]). The grids presented in this report are the same as those developed in Revision 01 (BSC 2003 [DIRS 160109]); however, the documentation of the development of the grids in Revision 02 has been updated to address technical inconsistencies and achieve greater transparency, readability, and traceability. The constraints, assumptions, and limitations associated with this report are discussed in the appropriate sections that follow

  12. Site investigation SFR. Hydrogeological modelling of SFR. Model version 0.2

    Energy Technology Data Exchange (ETDEWEB)

    Oehman, Johan (Golder Associates AB (Sweden)); Follin, Sven (SF GeoLogic (Sweden))

    2010-01-15

    The Swedish Nuclear Fuel and Waste Management Company (SKB) has conducted site investigations for a planned extension of the existing final repository for short-lived radioactive waste (SFR). A hydrogeological model is developed in three model versions, which will be used for safety assessment and design analyses. This report presents a data analysis of the currently available hydrogeological data from the ongoing Site Investigation SFR (KFR27, KFR101, KFR102A, KFR102B, KFR103, KFR104, and KFR105). The purpose of this work is to develop a preliminary hydrogeological Discrete Fracture Network model (hydro-DFN) parameterisation that can be applied in regional-scale modelling. During this work, the Geologic model had not yet been updated for the new data set. Therefore, all analyses were made to the rock mass outside Possible Deformation Zones, according to Single Hole Interpretation. Owing to this circumstance, it was decided not to perform a complete hydro-DFN calibration at this stage. Instead focus was re-directed to preparatory test cases and conceptual questions with the aim to provide a sound strategy for developing the hydrogeological model SFR v. 1.0. The presented preliminary hydro-DFN consists of five fracture sets and three depth domains. A statistical/geometrical approach (connectivity analysis /Follin et al. 2005/) was performed to estimate the size (i.e. fracture radius) distribution of fractures that are interpreted as Open in geologic mapping of core data. Transmissivity relations were established based on an assumption of a correlation between the size and evaluated specific capacity of geologic features coupled to inflows measured by the Posiva Flow Log device (PFL-f data). The preliminary hydro-DFN was applied in flow simulations in order to test its performance and to explore the role of PFL-f data. Several insights were gained and a few model technical issues were raised. These are summarised in Table 5-1

  13. Site investigation SFR. Hydrogeological modelling of SFR. Model version 0.2

    International Nuclear Information System (INIS)

    Oehman, Johan; Follin, Sven

    2010-01-01

    The Swedish Nuclear Fuel and Waste Management Company (SKB) has conducted site investigations for a planned extension of the existing final repository for short-lived radioactive waste (SFR). A hydrogeological model is developed in three model versions, which will be used for safety assessment and design analyses. This report presents a data analysis of the currently available hydrogeological data from the ongoing Site Investigation SFR (KFR27, KFR101, KFR102A, KFR102B, KFR103, KFR104, and KFR105). The purpose of this work is to develop a preliminary hydrogeological Discrete Fracture Network model (hydro-DFN) parameterisation that can be applied in regional-scale modelling. During this work, the Geologic model had not yet been updated for the new data set. Therefore, all analyses were made to the rock mass outside Possible Deformation Zones, according to Single Hole Interpretation. Owing to this circumstance, it was decided not to perform a complete hydro-DFN calibration at this stage. Instead focus was re-directed to preparatory test cases and conceptual questions with the aim to provide a sound strategy for developing the hydrogeological model SFR v. 1.0. The presented preliminary hydro-DFN consists of five fracture sets and three depth domains. A statistical/geometrical approach (connectivity analysis /Follin et al. 2005/) was performed to estimate the size (i.e. fracture radius) distribution of fractures that are interpreted as Open in geologic mapping of core data. Transmissivity relations were established based on an assumption of a correlation between the size and evaluated specific capacity of geologic features coupled to inflows measured by the Posiva Flow Log device (PFL-f data). The preliminary hydro-DFN was applied in flow simulations in order to test its performance and to explore the role of PFL-f data. Several insights were gained and a few model technical issues were raised. These are summarised in Table 5-1

  14. Hydrogeological modelling of the Atlantis aquifer for management ...

    African Journals Online (AJOL)

    The Atlantis Water Supply Scheme (AWSS, Western Cape, South Africa) has been in operation for about 40 years as a means to supply and augment drinking water to the town of Atlantis via managed aquifer recharge (MAR). In this study, the numerical model MODFLOW for groundwater flow and contaminant transport was ...

  15. Hydrogeological modelling as a tool for understanding rockslides evolution

    Science.gov (United States)

    Crosta, Giovanni B.; De Caro, Mattia; Frattini, Paolo; Volpi, Giorgio

    2015-04-01

    construction of the models, in particular the partition of the slope in different sectors with different hydraulic conductivities, are coherent with the geological, structural, hydrological and hydrogeological field and laboratory data. The sensitivity analysis shows that the hydraulic conductivity of some slope sectors (e.g. morphostructures, compressed or relaxed slope-toe, basal shear band) strongly influence the water table position and evolution. In transient models, the values of specific storage coefficient play a major control on the amplitude of groundwater level fluctuations, deriving from snowmelt or induced reservoir level rise. The calibrated groundwater flow-models are consistent with groundwater levels measured in the proximity of the piezometers aligned along the sections. The two examples can be considered important for a more advanced understanding of the evolution of rockslides and suggest the required set of data and modelling approaches both for seasonal and long term slope stability analyses. The use of the results of such analyses is reported, for both the case studies, in a companion abstract in session 3.7 where elasto-visco-plastic rheologies have been adopted for the shear band materials to replicate the available displacement time-series.

  16. Hydrogeologic Framework Model for the Saturated Zone Site Scale flow and Transport Model

    Energy Technology Data Exchange (ETDEWEB)

    T. Miller

    2004-11-15

    The purpose of this report is to document the 19-unit, hydrogeologic framework model (19-layer version, output of this report) (HFM-19) with regard to input data, modeling methods, assumptions, uncertainties, limitations, and validation of the model results in accordance with AP-SIII.10Q, Models. The HFM-19 is developed as a conceptual model of the geometric extent of the hydrogeologic units at Yucca Mountain and is intended specifically for use in the development of the ''Saturated Zone Site-Scale Flow Model'' (BSC 2004 [DIRS 170037]). Primary inputs to this model report include the GFM 3.1 (DTN: MO9901MWDGFM31.000 [DIRS 103769]), borehole lithologic logs, geologic maps, geologic cross sections, water level data, topographic information, and geophysical data as discussed in Section 4.1. Figure 1-1 shows the information flow among all of the saturated zone (SZ) reports and the relationship of this conceptual model in that flow. The HFM-19 is a three-dimensional (3-D) representation of the hydrogeologic units surrounding the location of the Yucca Mountain geologic repository for spent nuclear fuel and high-level radioactive waste. The HFM-19 represents the hydrogeologic setting for the Yucca Mountain area that covers about 1,350 km2 and includes a saturated thickness of about 2.75 km. The boundaries of the conceptual model were primarily chosen to be coincident with grid cells in the Death Valley regional groundwater flow model (DTN: GS960808312144.003 [DIRS 105121]) such that the base of the site-scale SZ flow model is consistent with the base of the regional model (2,750 meters below a smoothed version of the potentiometric surface), encompasses the exploratory boreholes, and provides a framework over the area of interest for groundwater flow and radionuclide transport modeling. In depth, the model domain extends from land surface to the base of the regional groundwater flow model (D'Agnese et al. 1997 [DIRS 100131], p 2). For the site

  17. Hydrogeologic Framework Model for the Saturated Zone Site Scale flow and Transport Model

    International Nuclear Information System (INIS)

    Miller, T.

    2004-01-01

    The purpose of this report is to document the 19-unit, hydrogeologic framework model (19-layer version, output of this report) (HFM-19) with regard to input data, modeling methods, assumptions, uncertainties, limitations, and validation of the model results in accordance with AP-SIII.10Q, Models. The HFM-19 is developed as a conceptual model of the geometric extent of the hydrogeologic units at Yucca Mountain and is intended specifically for use in the development of the ''Saturated Zone Site-Scale Flow Model'' (BSC 2004 [DIRS 170037]). Primary inputs to this model report include the GFM 3.1 (DTN: MO9901MWDGFM31.000 [DIRS 103769]), borehole lithologic logs, geologic maps, geologic cross sections, water level data, topographic information, and geophysical data as discussed in Section 4.1. Figure 1-1 shows the information flow among all of the saturated zone (SZ) reports and the relationship of this conceptual model in that flow. The HFM-19 is a three-dimensional (3-D) representation of the hydrogeologic units surrounding the location of the Yucca Mountain geologic repository for spent nuclear fuel and high-level radioactive waste. The HFM-19 represents the hydrogeologic setting for the Yucca Mountain area that covers about 1,350 km2 and includes a saturated thickness of about 2.75 km. The boundaries of the conceptual model were primarily chosen to be coincident with grid cells in the Death Valley regional groundwater flow model (DTN: GS960808312144.003 [DIRS 105121]) such that the base of the site-scale SZ flow model is consistent with the base of the regional model (2,750 meters below a smoothed version of the potentiometric surface), encompasses the exploratory boreholes, and provides a framework over the area of interest for groundwater flow and radionuclide transport modeling. In depth, the model domain extends from land surface to the base of the regional groundwater flow model (D'Agnese et al. 1997 [DIRS 100131], p 2). For the site-scale SZ flow model, the HFM

  18. Inverse modeling for the determination of hydrogeological parameters of a two-phase system

    International Nuclear Information System (INIS)

    Finsterle, S.

    1993-02-01

    Investigations related to the disposal of radioactive wastes in Switzerland consider formations containing natural gas as potential rocks for a repository. Moreover, gas generation in the repository itself may lead to an unsaturated zone of significant extent and impact on the system's performance. The site characterization procedure requires the estimation of hydraulic properties being used as input parameters for a two-phase two-component numerical simulator. In this study, estimates of gas-related formation parameters are obtained by inverse modeling. Based on discrete observations of the system's state, model parameters can be estimated within the framework of a given conceptual model by means of optimization techniques. This study presents the theoretical background that related field data to the model parameters. A parameter estimation procedure is proposed and implemented in a computer code for automatic model calibration. This tool allows identification of key parameters affecting flow of water and gas in porous media. The inverse modeling approach is verified using data from a synthetic laboratory experiment. In addition, the Gas test performed at the Grimsel Test Site is analyzed in order to demonstrate the applicability of the proposed procedure when used with data from a real geologic environment. Estimation of hydrogeologic parameters by automatic model calibration improves the understanding of the two-phase flow processes and therefore increases the reliability of the subsequent simulation runs. (author) figs., tabs., refs

  19. Inverse modeling for the determination of hydrogeological parameters of a two-phase system

    International Nuclear Information System (INIS)

    Finsterle, S.

    1993-01-01

    Investigations related to the disposal of radioactive wastes in Switzerland are dealing with formations containing natural gas as potential host rock for a repository. Moreover, gas generation in the repository itself may lead to an unsaturated zone of significant extent and impact on the system's performance. The site characterization procedure requires the estimation of hydraulic properties being used as input parameters for a two-phase two-component numerical simulator. In this study, estimates of gas related formation parameters are obtained by inverse modeling. Based on discrete observations of the system's state, model parameters can be estimated within the framework of a given conceptual model by means of optimization techniques. This study presents the theoretical background that relates field data to the model parameters. A parameter estimation procedure is proposed and implemented in a computer code for automatic model calibration. This tool allows to identify key parameters affecting flow of water and gas in porous media. The inverse modeling approach is verified using data from a synthetic laboratory experiment. In addition, the Gastest performed at the Grimsel Test Site is analyzed in order to demonstrate the applicability of the proposed procedure when used with data from a real geologic environment. Estimation of hydrogeologic parameters by automatic model calibration improves the understanding of the two-phase flow processes and therefore increases the reliability of the subsequent simulation runs. (author) figs., tabs., 100 refs

  20. Stepwise hydrogeological modeling and groundwater flow analysis on site scale (Step 0 and Step 1)

    International Nuclear Information System (INIS)

    Ohyama, Takuya; Saegusa, Hiromitsu; Onoe, Hironori

    2005-05-01

    One of the main goals of the Mizunami Underground Research Laboratory Project is to establish comprehensive techniques for investigation, analysis, and assessment of the deep geological environment. To achieve this goal, a variety of investigations, analysis, and evaluations have been conducted using an iterative approach. In this study, hydrogeological modeling and ground water flow analyses have been carried out using the data from surface-based investigations at Step 0 and Step 1, in order to synthesize the investigation results, to evaluate the uncertainty of the hydrogeological model, and to specify items for further investigation. The results of this study are summarized as follows: 1) As the investigation progresses Step 0 to Step 1, the understanding of groundwater flow was enhanced from Step 0 to Step 1, and the hydrogeological model could be revised, 2) The importance of faults as major groundwater flow pathways was demonstrated, 3) Geological and hydrogeological characteristics of faults with orientation of NNW and NE were shown to be especially significant. The main item specified for further investigations is summarized as follows: geological and hydrogeological characteristics of NNW and NE trending faults are important. (author)

  1. Hydrogeophysics and remote sensing for the design of hydrogeological conceptual models in hard rocks - Sardón catchment (Spain)

    OpenAIRE

    Francés, Alain; Lubczynski, Maciek W.; Roy, Jean; Santos, Fernando A. Monteiro; Ardekani, Mohammad R. Mahmoudzadeh

    2014-01-01

    Hard rock aquifers are highly heterogeneous and hydrogeologically complex. To contribute to the design of hydrogeological conceptual models of hard rock aquifers, we propose a multi-techniques methodology based on a downward approach that combines remote sensing (RS), non-invasive hydrogeophysics and hydrogeological field data acquisition. The proposed methodology is particularly suitable for data scarce areas. It was applied in the pilot research area of Sardón catchment (80 km2)...

  2. Numerical analysis of the hydrogeologic controls in a layered coastal aquifer system, Oahu, Hawaii, USA

    Science.gov (United States)

    Oki, Delwyn S.; Souza, William R.; Bolke, Edward L.; Bauer, Glenn R.

    The coastal aquifer system of southern Oahu, Hawaii, USA, consists of highly permeable volcanic aquifers overlain by weathered volcanic rocks and interbedded marine and terrestrial sediments of both high and low permeability. The weathered volcanic rocks and sediments are collectively known as caprock, because they impede the free discharge of groundwater from the underlying volcanic aquifers. A cross-sectional groundwater flow and transport model was used to evaluate the hydrogeologic controls on the regional flow system in southwestern Oahu. Controls considered were: (a) overall caprock hydraulic conductivity; and (b) stratigraphic variations of hydraulic conductivity in the caprock. Within the caprock, variations in hydraulic conductivity, caused by stratigraphy or discontinuities of the stratigraphic units, are a major control on the direction of groundwater flow and the distribution of water levels and salinity. Results of cross-sectional modeling confirm the general groundwater flow pattern that would be expected in a layered coastal system. Groundwater flow is: (a) predominantly upward in the low-permeability sedimentary units; and (b) predominantly horizontal in the high-permeability sedimentary units. Résumé Le système aquifère littoral du sud d'Oahu (Hawaii, États-Unis) est constitué par des aquifères de terrains volcaniques très perméables, recouverts par des roches volcaniques altérées, et interstratifiés avec des sédiments marins et continentaux de perméabilité aussi bien forte que faible. Les roches volcaniques altérées et les sédiments sont globalement considérés comme une couverture, parce qu'ils s'opposent à l'écoulement de l'eau souterraine provenant des aquifères volcaniques sous-jacents. Les contrôles hydrogéologiques sur le système aquifère régional du sud-ouest d'Oahu ont étéévaluées au moyen d'un modèle d'écoulement et de transport sur une section transversale. Ces contrôles prennent en compte la conductivit

  3. Structural geology and geophysics as a support to build a hydrogeologic model of granite rock

    Science.gov (United States)

    Martinez-Landa, Lurdes; Carrera, Jesús; Pérez-Estaún, Andrés; Gómez, Paloma; Bajos, Carmen

    2016-06-01

    A method developed for low-permeability fractured media was applied to understand the hydrogeology of a mine excavated in a granitic pluton. This method includes (1) identifying the main groundwater-conducting features of the medium, such as the mine, dykes, and large fractures, (2) implementing this factors as discrete elements into a three-dimensional numerical model, and (3) calibrating these factors against hydraulic data . A key question is how to identify preferential flow paths in the first step. Here, we propose a combination of several techniques. Structural geology, together with borehole sampling, geophysics, hydrogeochemistry, and local hydraulic tests aided in locating all structures. Integration of these data yielded a conceptual model of the site. A preliminary calibration of the model was performed against short-term (Model validity was tested by blind prediction of a long-term (4 months) large-scale (1 km) pumping test from the mine, which yielded excellent agreement with the observations. Model results confirmed the sparsely fractured nature of the pluton, which has not been subjected to glacial loading-unloading cycles and whose waters are of Na-HCO3 type.

  4. Numerical model CCC

    International Nuclear Information System (INIS)

    Bodvarsson, G.S.; Lippmann, M.J.

    1980-01-01

    The computer program CCC (conduction-convection-consolidation), developed at Lawrence Berkeley Laboratory, solves numerically the heat and mass flow equations for a fully saturated medium, and computes one-dimensional consolidation of the simulated systems. The model employs the Integrated Finite Difference Method (IFDM) in discretizing the saturated medium and formulating the governing equations. The sets of equations are solved either by an iterative solution technique (old version) or an efficient sparse solver (new version). The deformation of the medium is calculated using the one-dimensional consolidation theory of Terzaghi. In this paper, the numerical code is described, validation examples given and areas of application discussed. Several example problems involving flow through fractured media are also presented

  5. Hydrogeological model of the territory of Kowsar hydraulic project

    Directory of Open Access Journals (Sweden)

    Orekhov Vyacheslav Valentinovich

    2015-03-01

    Full Text Available Mathematical hydrogeology model of the territory of Kowsar Project was created with account for the results of the engineering surveys and hydro geological monitoring, which was conducted in the process of Kowsar Project construction. In order to create the model in the present work a universal computer system Ansys was used, which implements the finite element method and solid modeling technology, allowing to solve the filtration problem with the use of thermal analogy. The three-dimensional geometric model was built with use of the principle “hard body” modeling, which displays the main line of the territory relief, including the created water reservoir, geological structure (anticline Duk and the main lithological complexes developed within the territory. In the limestone mass As here is a zone characterized by water permeability on territory of Kowsar Project, and a layer characterized by seepage feeding, which occurs outside the considered territory. The water reservoir is a source of the change of hydro geological situation. The results of field observations witness, that the levels of underground waters within the area of the main structures reacts almost instantly on the water level change in the water reservoir; the delay period of levels change is not more than 1,5…2,0 weeks at maximum distance from the water reservoir. These particularities of the hydro geological regime allow using the steady-state scheme of the decision of forecast problems. The mass of limestone As, containing the structures of the Kowsar Project, is not homogeneous and anisotropy in its seepage characteristics. The heterogeneity is conditioned by exogenous influence on the mass up to the depth of 100…150 m. The seepage anisotropy of the mass is expressed by the difference of water permeability of the mass along and across the layers for almost one order. The structures of Kowsar Project is presented by a dam, grouting curtain on axis of the dam and

  6. A computer hydrogeologic model of the Nevada Test Site and surrounding region

    International Nuclear Information System (INIS)

    Gillson, R.; Hand, J.; Adams, P.; Lawrence, S.

    1996-01-01

    A three-dimensional, hydrogeologic model of the Nevada Test Site and surrounding region was developed as an element for regional groundwater flow and radionuclide transport models. The hydrogeologic model shows the distribution, thickness, and structural relationships of major aquifers and confining units, as conceived by a team of experts organized by the U.S. Department of Energy Nevada Operations Office. The model was created using Intergraph Corporation's Geographical Information System based Environmental Resource Management Application software. The study area encompasses more than 28,000 square kilometers in southern Nevada and Inyo County, California. Fifty-three geologic cross sections were constructed throughout the study area to provide a framework for the model. The lithology was simplified to 16 hydrostratigraphic units, and the geologic structures with minimal effect on groundwater flow were removed. Digitized cross sections, surface geology, and surface elevation data were the primary sources for the hydrogeologic model and database. Elevation data for the hydrostratigraphic units were posted, contoured, and gridded. Intergraph Corporation's three-dimensional visualization software, VOXEL trademark, was used to view the results interactively. The hydrogeologic database will be used in future flow modeling activities

  7. Numerical model SMODERP

    Science.gov (United States)

    Kavka, P.; Jeřábek, J.; Strouhal, L.

    2016-12-01

    The contribution presents a numerical model SMODERP that is used for calculation and prediction of surface runoff and soil erosion from agricultural land. The physically based model includes the processes of infiltration (Phillips equation), surface runoff routing (kinematic wave based equation), surface retention, surface roughness and vegetation impact on runoff. The model is being developed at the Department of Irrigation, Drainage and Landscape Engineering, Civil Engineering Faculty, CTU in Prague. 2D version of the model was introduced in last years. The script uses ArcGIS system tools for data preparation. The physical relations are implemented through Python scripts. The main computing part is stand alone in numpy arrays. Flow direction is calculated by Steepest Descent algorithm and in multiple flow algorithm. Sheet flow is described by modified kinematic wave equation. Parameters for five different soil textures were calibrated on the set of hundred measurements performed on the laboratory and filed rainfall simulators. Spatially distributed models enable to estimate not only surface runoff but also flow in the rills. Development of the rills is based on critical shear stress and critical velocity. For modelling of the rills a specific sub model was created. This sub model uses Manning formula for flow estimation. Flow in the ditches and streams are also computed. Numerical stability of the model is controled by Courant criterion. Spatial scale is fixed. Time step is dynamic and depends on the actual discharge. The model is used in the framework of the project "Variability of Short-term Precipitation and Runoff in Small Czech Drainage Basins and its Influence on Water Resources Management". Main goal of the project is to elaborate a methodology and online utility for deriving short-term design precipitation series, which could be utilized by a broad community of scientists, state administration as well as design planners. The methodology will account for

  8. Blueprint for a coupled model of sedimentology, hydrology, and hydrogeology in streambeds

    Science.gov (United States)

    Partington, Daniel; Therrien, Rene; Simmons, Craig T.; Brunner, Philip

    2017-06-01

    The streambed constitutes the physical interface between the surface and the subsurface of a stream. Across all spatial scales, the physical properties of the streambed control surface water-groundwater interactions. Continuous alteration of streambed properties such as topography or hydraulic conductivity occurs through erosion and sedimentation processes. Recent studies from the fields of ecology, hydrogeology, and sedimentology provide field evidence that sedimentological processes themselves can be heavily influenced by surface water-groundwater interactions, giving rise to complex feedback mechanisms between sedimentology, hydrology, and hydrogeology. More explicitly, surface water-groundwater exchanges play a significant role in the deposition of fine sediments, which in turn modify the hydraulic properties of the streambed. We explore these feedback mechanisms and critically review the extent of current interaction between the different disciplines. We identify opportunities to improve current modeling practices. For example, hydrogeological models treat the streambed as a static rather than a dynamic entity, while sedimentological models do not account for critical catchment processes such as surface water-groundwater exchange. We propose a blueprint for a new modeling framework that bridges the conceptual gaps between sedimentology, hydrogeology, and hydrology. Specifically, this blueprint (1) fully integrates surface-subsurface flows with erosion, transport, and deposition of sediments and (2) accounts for the dynamic changes in surface elevation and hydraulic conductivity of the streambed. Finally, we discuss the opportunities for new research within the coupled framework.

  9. Development of a hydrogeological conceptual wetland model in the data-scarce north-eastern region of Kilombero Valley, Tanzania

    Science.gov (United States)

    Burghof, Sonja; Gabiri, Geofrey; Stumpp, Christine; Chesnaux, Romain; Reichert, Barbara

    2018-02-01

    Understanding groundwater/surface-water interactions in wetlands is crucial because wetlands provide not only a high potential for agricultural production, but also sensitive and valuable ecosystems. This is especially true for the Kilombero floodplain wetland in Tanzania, which represents a data-scarce region in terms of hydrological and hydrogeological data. A comprehensive approach combining hydrogeological with tracer-based assessments was conducted, in order to develop a conceptual hydrogeological wetland model of the area around the city of Ifakara in the north-eastern region of Kilombero catchment. Within the study site, a heterogeneous porous aquifer, with a range of hydraulic conductivities, is underlain by a fractured-rock aquifer. Groundwater chemistry is mainly influenced by silicate weathering and depends on groundwater residence times related to the hydraulic conductivities of the porous aquifer. Groundwater flows from the hillside to the river during most of the year. While floodwater close to the river is mainly derived from overbank flow of the river, floodwater at a greater distance from the river mainly originates from precipitation and groundwater discharge. Evaporation effects in floodwater increase with increasing distance from the river. In general, the contribution of flood and stream water to groundwater recharge is negligible. In terms of an intensification of agricultural activities in the wetland, several conclusions can be drawn from the conceptual model. Results of this study are valuable as a base for further research related to groundwater/surface-water interactions and the conceptual model can be used in the future to set up numerical flow and transport models.

  10. Hydrogeologic controls on saturation profiles in heat-pipe-like hydrothermal systems: numerical study

    Science.gov (United States)

    Pervin, Mollika; Ghergut, Iulia; Graf, Thomas; Peche, Aaron

    2016-04-01

    work, we explore some mechanisms and geologic controls that can lead to the formation of extensive vapor-dominated zones within a two-phase system. In particular, we investigate the effect of vertical heterogeneity of permeability (stratified reservoir, containing a permeability barrier) on the liquid water saturation profile within a modified HP model. Though in field observations liquid water has been directly encountered only within the condensation zone at reservoir top, it was speculated that large amounts of liquid water might also exist below the condensation zone. This is of great practical significance to the exploitation of vapor-dominated reservoirs, as their longevity depends on the fluid reserves in place. Within this work, we demonstrate by numerical simulations of a modified HP model that high values of liquid water saturation (>0.8) can prevail even far below the condensation zone. Such findings are useful as a baseline for future calculations regarding the economic exploitation of vapor-dominated systems, where premature productivity drop (or dry-out) is the main issue of concern. References: Eastman, G. Y:, 1968: The heat pipe. Scientific American, 218(5):38-46. Preuss, K. A., 1985: A quantitative model of vapor-dominated geothermal reservoirs as heat pipes in fractured porous rock, Transactions, Geothermal Resources. Council, 9(2), 353-361. Truesdell, A. H., and White, D.E. 1973: Production of superheated Steam from Vapor- dominated geothermal reservoirs. Geothermics, 2(3-4), 154-173

  11. Clustering and Bayesian hierarchical modeling for the definition of informative prior distributions in hydrogeology

    Science.gov (United States)

    Cucchi, K.; Kawa, N.; Hesse, F.; Rubin, Y.

    2017-12-01

    In order to reduce uncertainty in the prediction of subsurface flow and transport processes, practitioners should use all data available. However, classic inverse modeling frameworks typically only make use of information contained in in-situ field measurements to provide estimates of hydrogeological parameters. Such hydrogeological information about an aquifer is difficult and costly to acquire. In this data-scarce context, the transfer of ex-situ information coming from previously investigated sites can be critical for improving predictions by better constraining the estimation procedure. Bayesian inverse modeling provides a coherent framework to represent such ex-situ information by virtue of the prior distribution and combine them with in-situ information from the target site. In this study, we present an innovative data-driven approach for defining such informative priors for hydrogeological parameters at the target site. Our approach consists in two steps, both relying on statistical and machine learning methods. The first step is data selection; it consists in selecting sites similar to the target site. We use clustering methods for selecting similar sites based on observable hydrogeological features. The second step is data assimilation; it consists in assimilating data from the selected similar sites into the informative prior. We use a Bayesian hierarchical model to account for inter-site variability and to allow for the assimilation of multiple types of site-specific data. We present the application and validation of the presented methods on an established database of hydrogeological parameters. Data and methods are implemented in the form of an open-source R-package and therefore facilitate easy use by other practitioners.

  12. 3D geological and hydrogeological modeling as design tools for the Conawapa generating station

    Energy Technology Data Exchange (ETDEWEB)

    Mann, J.; Sharif, S.; Smith, B. [KGS Group, Winnipeg, MB (Canada); Cook, G.N.; Osiowy, B.J. [Manitoba Hydro, Winnipeg, MB (Canada)

    2008-07-01

    Following the project's suspension in the early 1990s, part of Manitoba Hydro's recommitment study involved digital modeling of geological and hydrogeological data for the foundation design and analysis of the proposed Conawapa generating station in northern Manitoba. Three-dimensional geological and hydrogeological models have been developed to consolidate and improve the designer's ability to understand all of the information, and to assist in developing engineering alternatives which will improve the overall confidence of the design. The tools are also being leveraged for use in environmental studies. This paper provided an overview of the Conawapa site and 3-dimensional modeling goals. It described the geology and hydrogeology of the Conawapa site as well as the bedrock structure and Karst development. The paper also presented the central concepts of 3-dimensional modeling studies, including the flow of information from database to modeling software platforms. The construction of the Conawapa geological model was also presented, with particular reference to an overview of the MVS software; mesh design; and model buildup logic. The construction of the Conawapa hydrogeological model was discussed in terms of the finite element code FEFLOW software; conceptual model design; and initial observations of Conawapa groundwater flow modeling. It was concluded that recent advancement and application of 3-dimensional geological visualization software to engineering and environmental projects, including at the future Conawapa site using MVS and FEFLOW, have shown that complicated geological data can be organized, displayed, and analysed in a systematic way, to improve site visualization, understanding, and data relationships. 19 refs., 9 figs.

  13. Characterization and hydrogeological modelling of a site for disposal of medium- and low-level radioactive waste

    International Nuclear Information System (INIS)

    Lavie, J.; Peaudecerf, P.

    1993-01-01

    Characterization studies of the French low-and intermediate-level radwaste site in the Aube Department includes a significant hydrogeological appraisal element. These studies are based upon geological, hydrogeological, and hydrodynamic measurements. The data are compiled into a model of the ground water- body. Data collection is continuous. The hydrodynamic model and the transport model is regularly validated for ANDRA (French National Radioactive Waste Disposal Agency) with a reliable and up-dated tool

  14. Coupled hydrogeological and reactive transport modelling of the Simpevarp area (Sweden)

    International Nuclear Information System (INIS)

    Molinero, Jorge; Raposo, Juan R.; Galindez, Juan M.; Arcos, David; Guimera, Jordi

    2008-01-01

    The Simpevarp area is one of the alternative sites being considered for the deep geological disposal of high level radioactive waste in Sweden. In this paper, a coupled regional groundwater flow and reactive solute transport model of the Simpevarp area is presented that integrates current hydrogeological and hydrochemical data of the area. The model simulates the current hydrochemical pattern of the groundwater system in the area. To that aim, a conceptual hydrochemical model was developed in order to represent the dominant chemical processes. Groundwater flow conditions were reproduced by taking into account fluid-density-dependent groundwater flow and regional hydrogeologic boundary conditions. Reactive solute transport calculations were performed on the basis of the velocity field so obtained. The model was calibrated and sensitivity analyses were carried out in order to investigate the effects of heterogeneities of hydraulic conductivity in the subsurface medium. Results provided by the reactive transport model are in good agreement with much of the measured hydrochemical data. This paper emphasizes the appropriateness of the use of reactive solute transport models when water-rock interaction reactions are involved, and demonstrates what powerful tools they are for the interpretation of hydrogeological and hydrochemical data from site geological repository characterization programs, by providing a qualitative framework for data analysis and testing of conceptual assumptions in a process-oriented approach

  15. Summary of discrete fracture network modelling as applied to hydrogeology of the Forsmark and Laxemar sites

    International Nuclear Information System (INIS)

    Hartley, Lee; Roberts, David

    2013-04-01

    The Swedish Nuclear Fuel and Waste Management Company (SKB) is responsible for the development of a deep geological repository for spent nuclear fuel. The permitting of such a repository is informed by assessment studies to estimate the risks of the disposal method. One of the potential risks involves the transport of radionuclides in groundwater from defective canisters in the repository to the accessible environment. The Swedish programme for geological disposal of spent nuclear fuel has involved undertaking detailed surface-based site characterisation studies at two different sites, Forsmark and Laxemar-Simpevarp. A key component of the hydrogeological modelling of these two sites has been the development of Discrete Fracture Network (DFN) concepts of groundwater flow through the fractures in the crystalline rocks present. A discrete fracture network model represents some of the characteristics of fractures explicitly, such as their, orientation, intensity, size, spatial distribution, shape and transmissivity. This report summarises how the discrete fracture network methodology has been applied to model groundwater flow and transport at Forsmark and Laxemar. The account has involved summarising reports previously published by SKB between 2001 and 2011. The report describes the conceptual framework and assumptions used in interpreting site data, and in particular how data has been used to calibrate the various parameters that define the discrete fracture network representation of bedrock hydrogeology against borehole geologic and hydraulic data. Steps taken to confirm whether the developed discrete fracture network models provide a description of regional-scale groundwater flow and solute transport consistent with wider hydraulic tests hydrochemical data from Forsmark and Laxemar are discussed. It illustrates the use of derived hydrogeological DFN models in the simulations of the temperate period hydrogeology that provided input to radionuclide transport

  16. Summary of discrete fracture network modelling as applied to hydrogeology of the Forsmark and Laxemar sites

    Energy Technology Data Exchange (ETDEWEB)

    Hartley, Lee; Roberts, David

    2013-04-15

    The Swedish Nuclear Fuel and Waste Management Company (SKB) is responsible for the development of a deep geological repository for spent nuclear fuel. The permitting of such a repository is informed by assessment studies to estimate the risks of the disposal method. One of the potential risks involves the transport of radionuclides in groundwater from defective canisters in the repository to the accessible environment. The Swedish programme for geological disposal of spent nuclear fuel has involved undertaking detailed surface-based site characterisation studies at two different sites, Forsmark and Laxemar-Simpevarp. A key component of the hydrogeological modelling of these two sites has been the development of Discrete Fracture Network (DFN) concepts of groundwater flow through the fractures in the crystalline rocks present. A discrete fracture network model represents some of the characteristics of fractures explicitly, such as their, orientation, intensity, size, spatial distribution, shape and transmissivity. This report summarises how the discrete fracture network methodology has been applied to model groundwater flow and transport at Forsmark and Laxemar. The account has involved summarising reports previously published by SKB between 2001 and 2011. The report describes the conceptual framework and assumptions used in interpreting site data, and in particular how data has been used to calibrate the various parameters that define the discrete fracture network representation of bedrock hydrogeology against borehole geologic and hydraulic data. Steps taken to confirm whether the developed discrete fracture network models provide a description of regional-scale groundwater flow and solute transport consistent with wider hydraulic tests hydrochemical data from Forsmark and Laxemar are discussed. It illustrates the use of derived hydrogeological DFN models in the simulations of the temperate period hydrogeology that provided input to radionuclide transport

  17. Development of Numerical Grids for UZ Flow and Transport Modeling

    International Nuclear Information System (INIS)

    P. Dobson

    2003-01-01

    This Scientific Analysis report describes the methods used to develop numerical grids of the unsaturated hydrogeologic system beneath Yucca Mountain. Numerical grid generation is an integral part of the development of the Unsaturated Zone Flow and Transport Model (UZ Model), a complex, three-dimensional (3-D) model of Yucca Mountain. This revision incorporates changes made to both the geologic framework model and the proposed repository layout. The resulting numerical grids, developed using current geologic, hydrogeologic, and mineralogic data, provide the necessary framework to: (1) develop calibrated hydrogeologic property sets and flow fields, (2) test conceptual hypotheses of flow and transport, and (3) predict flow and transport behavior under a variety of climatic and thermal-loading conditions. The technical scope, content, and management of this Scientific Analysis report was initially controlled by the planning document, ''Technical Work Plan (TWP) for: Unsaturated Zone Sections of License Application Chapters 8 and 12'' (BSC 2002 [159051], Section 1.6.4). This TWP was later superseded by ''Technical Work Plan for: Performance Assessment Unsaturated Zone'' (BSC 2002 [160819]), which contains the Data Qualification Plan used to qualify the DTN: MO0212GWLSSPAX.000 [161271] (See Attachment IV). Grids generated and documented in this report supersede those documented in previous versions of this report (BSC 2001 [159356]). The constraints, assumptions, and limitations associated with this report are discussed in the appropriate sections that follow. There were no deviations from the TWP scope of work in this report. Two software packages not listed in Table IV-2 of the TWP (BSC 2002 [159051]), ARCINFO V7.2.1 (CRWMS M and O 2000 [157019]; USGS 2000 [148304]) and 2kgrid8.for V1.0 (LBNL 2002 [154787]), were utilized in the development of the numerical grids; the use of additional software is accounted for in the TWP (BSC 2002 [159051], Section 13). The use of

  18. Stepwise hydrogeological modeling and groundwater flow analysis on site scale (step 2)

    International Nuclear Information System (INIS)

    Onoe, Hironori; Saegusa, Hiromitsu; Endo, Yoshinobu

    2005-02-01

    One of the main goals of the Mizunami Underground Research Laboratory Project is to establish comprehensive techniques for investigation, analysis, and assessment of the deep geological environment. To achieve this goal, a variety of investigations are being conducted using an iterative approach. In this study, hydrogeological modeling and groundwater flow analyses have been carried out using the data from surface-based investigations at Step 2, in order to synthesize the investigation results, to evaluate the uncertainty of the hydrogeological model, and to specify items for further investigation. The results of this study are summarized as follows: 1) The understanding of groundwater flow is enhanced, and the hydrogeological model has renewed; 2) The importance of faults as major groundwater flow pathways has been demonstrated; 3) The importance of iterative approach as progress of investigations has been demonstrated; 4) Geological and hydraulic characteristics of faults with orientation of NNW, NW and NE were shown to be especially significant; 5) the hydraulic properties of the Lower Sparsely Fractured Domain (LSFD) significantly influence the groundwater flow. The main items specified for further investigations are summarized as follows: 1) Geological and hydraulic characteristics of NNW, NW and NE trending faults; 2) Hydraulic properties of the LSFD; 3) More accuracy upper and lateral boundary conditions of the site scale model. (author)

  19. A hydrogeological conceptual model of the Suio hydrothermal area (central Italy)

    Science.gov (United States)

    Saroli, Michele; Lancia, Michele; Albano, Matteo; Casale, Anna; Giovinco, Gaspare; Petitta, Marco; Zarlenga, Francesco; dell'Isola, Marco

    2017-09-01

    A hydrogeological conceptual model has been developed that describes the hydrothermal system of Suio Terme (central Italy). The studied area is located along the peri-Tyrrhenian zone of the central Apennines, between the Mesozoic and Cenozoic carbonate platform sequences of the Aurunci Mountains and the volcanic sequences of the Roccamonfina. A multi-disciplinary approach was followed, using new hydrogeological surveys, the interpretation of stratigraphic logs of boreholes and water wells, and geophysical data—seismic sections, shear-wave velocity (Vs) crustal model and gravimetric model. The collected information allowed for construction of a conceptual hydrogeological model and characterization of the hydrothermal system. The Suio hydrothermal system is strongly influenced by the Eastern Aurunci hydrostructure. Along the southeastern side, the top of the hydrostructure sinks to -1,000 m relative to sea level via a series of normal faults which give origin to the Garigliano graben. Geological and hydrogeological data strongly suggest the propagation and mixing of hot fluids, with cold waters coming from the shallow karst circuit. The aquitard distribution, the normal tectonic displacements and the fracturing of the karst hydrostructure strongly influence the hydrothermal basin. Carbon dioxide and other gasses play a key role in the whole circuit, facilitating the development of the hydrothermal system. The current level of knowledge suggests that the origin of the Suio hydrothermalism is the result of interaction between the carbonate reservoir of the Eastern Aurunci Mountains and the hot and deep crust of this peri-Tyrrhenian sector, where the Roccamonfina volcano represents the shallowest expression.

  20. Coupling of hydrogeological models with hydrogeophysical data to characterize seawater intrusion and shallow geothermal systems

    Science.gov (United States)

    Beaujean, J.; Kemna, A.; Engesgaard, P. K.; Hermans, T.; Vandenbohede, A.; Nguyen, F.

    2013-12-01

    While coastal aquifers are being stressed due to climate changes and excessive groundwater withdrawals require characterizing efficiently seawater intrusion (SWI) dynamics, production of geothermal energy is increasingly being used to hinder global warming. To study these issues, we need both robust measuring technologies and reliable predictions based on numerical models. SWI models are currently calibrated using borehole observations. Similarly, geothermal models depend mainly on the temperature field at few locations. Electrical resistivity tomography (ERT) can be used to improve these models given its high sensitivity to TDS and temperature and its relatively high lateral resolution. Inherent geophysical limitations, such as the resolution loss, can affect the overall quality of the ERT images and also prevent the correct recovery of the desired hydrochemical property. We present an uncoupled and coupled hydrogeophysical inversion to calibrate SWI and thermohydrogeologic models using ERT. In the SWI models, we demonstrate with two synthetic benchmarks (homogeneous and heterogeneous coastal aquifers) the ability of cumulative sensitivity-filtered ERT images using surface-only data to recover the hydraulic conductivity. Filtering of ERT-derived data at depth, where resolution is poorer, and the model errors make the dispersivity more difficult to estimate. In the coupled approach, we showed that parameter estimation is significantly improved because regularization bias is replaced by forward modeling only. Our efforts are currently focusing on applying the uncoupled/coupled approaches on a real life case study using field data from the site of Almeria, SE Spain. In the thermohydrogeologic models, the most sensitive hydrologic parameters responsible for heat transport are estimated from surface ERT-derived temperatures and ERT resistance data. A real life geothermal experiment that took place on the Campus De Sterre of Ghent University, Belgium and a synthetic

  1. Hydrogeological characterisation and modelling of deformation zones and fracture domains, Forsmark modelling stage 2.2

    Energy Technology Data Exchange (ETDEWEB)

    Follin, Sven (SF GeoLogic AB, Taeby (SE)); Leven, Jakob (Swedish Nuclear Fuel and Waste Management Co., Stockholm (SE)); Hartley, Lee; Jackson, Peter; Joyce, Steve; Roberts, David; Swift, Ben (Serco Assurance, Harwell (GB))

    2007-09-15

    The work reported here collates the structural-hydraulic information gathered in 21 cored boreholes and 32 percussion-drilled boreholes belonging to Forsmark site description, modelling stage 2.2. The analyses carried out provide the hydrogeological input descriptions of the bedrock in Forsmark needed by the end users Repository Engineering, Safety Assessment and Environmental Impact Assessment; that is, hydraulic properties of deformation zones and fracture domains. The same information is also needed for constructing 3D groundwater flow models of the Forsmark site and surrounding area. The analyses carried out render the following conceptual model regarding the observed heterogeneity in deformation zone transmissivity: We find the geological division of the deterministically modelled deformation zones into eight categories (sets) useful from a hydrogeological point of view. Seven of the eight categories are steeply dipping, WNW, NW, NNW, NNE, NE, ENE and EW, and on is gently dipping, G. All deformation zones, regardless of orientation (strike and dip), are subjected to a substantial decrease in transmissivity with depth. The data gathered suggest a contrast of c. 20,000 times for the uppermost one kilometre of bedrock, i.e. more than four orders of magnitude. The hydraulic properties below this depth are not investigated. The lateral heterogeneity is also substantial but more irregular in its appearance. For instance, for a given elevation and deformation zone category (orientation), the spatial variability in transmissivity within a particular deformation zone appears to be as large as the variability between all deformation zones. This suggests that the lateral correlation length is shorter than the shortest distance between two adjacent observation points and shorter than the category spacing. The observation that the mean transmissivity of the gently-dipping deformation zones is c. one to two orders of magnitude greater than the mean transmissivities of all

  2. Uncertainty in geological and hydrogeological data

    Directory of Open Access Journals (Sweden)

    B. Nilsson

    2007-09-01

    Full Text Available Uncertainty in conceptual model structure and in environmental data is of essential interest when dealing with uncertainty in water resources management. To make quantification of uncertainty possible is it necessary to identify and characterise the uncertainty in geological and hydrogeological data. This paper discusses a range of available techniques to describe the uncertainty related to geological model structure and scale of support. Literature examples on uncertainty in hydrogeological variables such as saturated hydraulic conductivity, specific yield, specific storage, effective porosity and dispersivity are given. Field data usually have a spatial and temporal scale of support that is different from the one on which numerical models for water resources management operate. Uncertainty in hydrogeological data variables is characterised and assessed within the methodological framework of the HarmoniRiB classification.

  3. Hydrogeological modelling of the Atlantis aquifer for management ...

    African Journals Online (AJOL)

    2017-01-01

    Jan 1, 2017 ... technology is viewed as promising to reduce water losses and recycle water, in particular in .... recharge basins (CRBs along the coast), production boreholes and a water ..... negligible groundwater reserve. Figure 7. Figure 7 ..... VAN BREUKELEN BM (2012) A post audit and inverse modeling in reactive ...

  4. Stability analysis of rockmass using a hydrogeologic model of groundwater flow at an underground limestone mine in Korea

    Science.gov (United States)

    Baek, H.; Kim, D.; Kim, G.; Kim, D.; Cheong, S.

    2017-12-01

    The safety and environmental issues should be addressed for sustainable mining operations. One of the key factors is the groundwater flow into underground mine workings, which will affect the overall workability and efficiency of the mining operation. Prediction of the groundwater inflow requires a detailed knowledge of the geologic conditions, including the presence of major faults and other geologic structures at the mine site. The hydrologic boundaries and depth of the phreatic surface of the mine area, as well as other relevant properties of the rockmass, are also provided. The stability of underground structures, in terms of the maximum stresses and deformations within the rockmass, can be analyzed using either the total stress or the effective stress approaches. Both the dried and saturated conditions should be considered with appropriate safety factors, as the distribution of the water pressure within the rockmass resulted from the groundwater flow directly affects the stability. In some cases, the rockmass rating systems such as the RMR and Q-systems are also applied. Various numerical codes have been used to construct the hydrogeologic models of mine sites, and the MINEDW by Itasca is one of those groundwater flow model codes developed to simulate groundwater flow related to mining. In this study, with a 3D hydrogeologic model constructed using the MINEDW for an underground limestone mine, the rate of mine water inflow and the porewater pressure were estimated. The stability of mine pillars and adits was analyzed adopting the porewater pressure and effective stress developed in the rockmass. The results were also compared with those from other 2D stability analysis procedures.

  5. Modeling of water transfer to aquifers: application to the determination of groundwater recharge by inversion in a complex hydrogeological system

    International Nuclear Information System (INIS)

    Hassane-Mamadou-Maina, Fadji-Zaouna

    2016-01-01

    Groundwater is the main available water resource for many countries; they are mainly replenished by water from precipitation, called groundwater recharge. Due to its great importance, management of groundwater resources is more essential than ever, and is achieved through mathematical models which offer us a better understanding of physical phenomena as well as their prediction. Hydrogeological Systems are generally complex thus characterized by a highly variable dynamic over time and space. These complexities have attracted the attention of many hydro geologists and many sophisticated models that can handle these issues and describe these Systems accurately were developed. Unfortunately, modeling groundwater recharge is still a challenge in groundwater resource management. Generally, groundwater models are used to simulate aquifers flow without a good estimation of recharge and its spatial-temporal distribution. as groundwater recharge rates show spatial-temporal variability due to climatic conditions, land use, and hydrogeological heterogeneity, these methods have limitations in dealing with these characteristics. To overcome these limitations, a coupled model which simulates flow in the unsaturated zone and recharge as well as groundwater flow was developed. The flow in the unsaturated zone is solved either with resolution of Richards equation or with empirical models while the diffusivity equation governs flow in the saturated zone. Robust numerical methods were used to solve these equations: we apply nonconforming finite element to solve the diffusivity equation and we used an accurate and efficient method for solving the Richards equation. In the natural environments, parameters that control these hydrological mechanisms aren't accurately known or even unknowns, only variations of piezometric heads are commonly available. Hence, ail parameters related to unsaturated and saturated flows will be identified by using only these piezometric data

  6. Numerical modelling of mine workings.

    CSIR Research Space (South Africa)

    Lightfoot, N

    1999-03-01

    Full Text Available to cover most of what is required for a practising rock mechanics engineer to be able to use any of these five programs to solve practical mining problems. The chapters on specific programs discuss their individual strengths and weaknesses and highlight... and applications of numerical modelling in the context of the South African gold and platinum mining industries. This includes an example that utilises a number of different numerical 3 modelling programs to solve a single problem. This particular example...

  7. Hydrogeological Site Descriptive Model - a strategy for its development during Site Investigations

    Energy Technology Data Exchange (ETDEWEB)

    Rhen, Ingvar [SWECO VIAK AB, Goeteborg (Sweden); Follin, Sven [SF GeoLogic AB, Stockholm (Sweden); Hermanson, Jan [Golder Associates, Stockholm (Sweden)

    2003-04-01

    The report is to present a strategy for the development of the Site Descriptive Hydrogeological Model within the SKB Site Investigation Programme. The report, and similar reports from the Geology, Rock Mechanics, Thermal properties, Hydrogeochemistry, Transport Properties and Surface Ecosystem disciplines are intended to guide SKB Site Descriptive Modelling but also to provide the authorities with an overview of how the modelling should be performed. Thus the objectives of this report are to: provide guidelines for the modelling of different sites resulting in consistent handling of modelling issues during the Site Investigations, provide a structure for the modelling sequence that is suitable for the establishment of a Site Descriptive model and provide some necessary details that should be considered in a Site Descriptive model.

  8. Hydrogeological Site Descriptive Model - a strategy for its development during Site Investigations

    International Nuclear Information System (INIS)

    Rhen, Ingvar; Follin, Sven; Hermanson, Jan

    2003-04-01

    The report is to present a strategy for the development of the Site Descriptive Hydrogeological Model within the SKB Site Investigation Programme. The report, and similar reports from the Geology, Rock Mechanics, Thermal properties, Hydrogeochemistry, Transport Properties and Surface Ecosystem disciplines are intended to guide SKB Site Descriptive Modelling but also to provide the authorities with an overview of how the modelling should be performed. Thus the objectives of this report are to: provide guidelines for the modelling of different sites resulting in consistent handling of modelling issues during the Site Investigations, provide a structure for the modelling sequence that is suitable for the establishment of a Site Descriptive model and provide some necessary details that should be considered in a Site Descriptive model

  9. Numerical modeling of economic uncertainty

    DEFF Research Database (Denmark)

    Schjær-Jacobsen, Hans

    2007-01-01

    Representation and modeling of economic uncertainty is addressed by different modeling methods, namely stochastic variables and probabilities, interval analysis, and fuzzy numbers, in particular triple estimates. Focusing on discounted cash flow analysis numerical results are presented, comparisons...... are made between alternative modeling methods, and characteristics of the methods are discussed....

  10. Index-based groundwater vulnerability mapping models using hydrogeological settings: A critical evaluation

    International Nuclear Information System (INIS)

    Kumar, Prashant; Bansod, Baban K.S.; Debnath, Sanjit K.; Thakur, Praveen Kumar; Ghanshyam, C.

    2015-01-01

    Groundwater vulnerability maps are useful for decision making in land use planning and water resource management. This paper reviews the various groundwater vulnerability assessment models developed across the world. Each model has been evaluated in terms of its pros and cons and the environmental conditions of its application. The paper further discusses the validation techniques used for the generated vulnerability maps by various models. Implicit challenges associated with the development of the groundwater vulnerability assessment models have also been identified with scientific considerations to the parameter relations and their selections. - Highlights: • Various index-based groundwater vulnerability assessment models have been discussed. • A comparative analysis of the models and its applicability in different hydrogeological settings has been discussed. • Research problems of underlying vulnerability assessment models are also reported in this review paper

  11. Index-based groundwater vulnerability mapping models using hydrogeological settings: A critical evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Prashant, E-mail: prashantkumar@csio.res.in [CSIR-Central Scientific Instruments Organisation, Chandigarh 160030 (India); Academy of Scientific and Innovative Research—CSIO, Chandigarh 160030 (India); Bansod, Baban K.S.; Debnath, Sanjit K. [CSIR-Central Scientific Instruments Organisation, Chandigarh 160030 (India); Academy of Scientific and Innovative Research—CSIO, Chandigarh 160030 (India); Thakur, Praveen Kumar [Indian Institute of Remote Sensing (ISRO), Dehradun 248001 (India); Ghanshyam, C. [CSIR-Central Scientific Instruments Organisation, Chandigarh 160030 (India); Academy of Scientific and Innovative Research—CSIO, Chandigarh 160030 (India)

    2015-02-15

    Groundwater vulnerability maps are useful for decision making in land use planning and water resource management. This paper reviews the various groundwater vulnerability assessment models developed across the world. Each model has been evaluated in terms of its pros and cons and the environmental conditions of its application. The paper further discusses the validation techniques used for the generated vulnerability maps by various models. Implicit challenges associated with the development of the groundwater vulnerability assessment models have also been identified with scientific considerations to the parameter relations and their selections. - Highlights: • Various index-based groundwater vulnerability assessment models have been discussed. • A comparative analysis of the models and its applicability in different hydrogeological settings has been discussed. • Research problems of underlying vulnerability assessment models are also reported in this review paper.

  12. Use of Multi-class Empirical Orthogonal Function for Identification of Hydrogeological Parameters and Spatiotemporal Pattern of Multiple Recharges in Groundwater Modeling

    Science.gov (United States)

    Huang, C. L.; Hsu, N. S.; Yeh, W. W. G.; Hsieh, I. H.

    2017-12-01

    This study develops an innovative calibration method for regional groundwater modeling by using multi-class empirical orthogonal functions (EOFs). The developed method is an iterative approach. Prior to carrying out the iterative procedures, the groundwater storage hydrographs associated with the observation wells are calculated. The combined multi-class EOF amplitudes and EOF expansion coefficients of the storage hydrographs are then used to compute the initial gauss of the temporal and spatial pattern of multiple recharges. The initial guess of the hydrogeological parameters are also assigned according to in-situ pumping experiment. The recharges include net rainfall recharge and boundary recharge, and the hydrogeological parameters are riverbed leakage conductivity, horizontal hydraulic conductivity, vertical hydraulic conductivity, storage coefficient, and specific yield. The first step of the iterative algorithm is to conduct the numerical model (i.e. MODFLOW) by the initial guess / adjusted values of the recharges and parameters. Second, in order to determine the best EOF combination of the error storage hydrographs for determining the correction vectors, the objective function is devised as minimizing the root mean square error (RMSE) of the simulated storage hydrographs. The error storage hydrograph are the differences between the storage hydrographs computed from observed and simulated groundwater level fluctuations. Third, adjust the values of recharges and parameters and repeat the iterative procedures until the stopping criterion is reached. The established methodology was applied to the groundwater system of Ming-Chu Basin, Taiwan. The study period is from January 1st to December 2ed in 2012. Results showed that the optimal EOF combination for the multiple recharges and hydrogeological parameters can decrease the RMSE of the simulated storage hydrographs dramatically within three calibration iterations. It represents that the iterative approach that

  13. Hydrogeologic evaluation and numerical simulation of the Death Valley regional ground-water flow system, Nevada and California

    International Nuclear Information System (INIS)

    D'Agnese, F.A.; Faunt, C.C.; Turner, A.K.; Hill, M.C.

    1997-01-01

    Yucca Mountain is being studied as a potential site for a high-level radioactive waste repository. In cooperation with the U.S. Department of Energy, the U.S. Geological Survey is evaluating the geologic and hydrologic characteristics of the ground-water system. The study area covers approximately 100,000 square kilometers between lat 35 degrees N., long 115 degrees W and lat 38 degrees N., long 118 degrees W and encompasses the Death Valley regional ground-water flow system. Hydrology in the region is a result of both the and climatic conditions and the complex described as dominated by interbasinal flow and may be conceptualized as having two main components: a series of relatively shallow and localized flow paths that are superimposed on deeper regional flow paths. A significant component of the regional ground-water flow is through a thick Paleozoic carbonate rock sequence. Throughout the regional flow system, ground-water flow is probably controlled by extensive and prevalent structural features that result from regional faulting and fracturing. Hydrogeologic investigations over a large and hydrogeologically complex area impose severe demands on data management. This study utilized geographic information systems and geoscientific information systems to develop, store, manipulate, and analyze regional hydrogeologic data sets describing various components of the ground-water flow system

  14. Hydrogeological study

    International Nuclear Information System (INIS)

    Massa, E.; Heinzen, W.; Santana, J.

    1987-01-01

    This work shows the hydrogeological study and well drilling carried out in the Teaching Formation Institute San Jose de Mayo Province Uruguay. It was developed a geological review in the National Directorate of Geology and Mining data base as well as field working, geology and hydrogeology recognition and area well drilling inventory.

  15. Development of a Hydrogeological Model of the Borrowdale Volcanics at Sellafield

    Science.gov (United States)

    Lunn, R. J.; Lunn, A. D.; Mackay, R.

    This work has arisen out of recent developments within the radioactive waste research programme managed by Her Majesty's Inspectorate of Pollution, UK (HMIP)*, to develop an integrated flow and transport model for the potential deep radioactive waste repository at Sellafield. One of the largest sources of uncertainty in model predictions, is the characterisation of the hydrogeological properties of the underlying strata, in particular, of the Borrowdale Volcanic Group (BVG) within which the repository is to be located. Analysis of the available borehole data (that released by the proponent company, Nirex, by December 1995) for the BVG formation has indicated a dual regime consisting of flow within faults and flow within the matrix (or an equivalent porous medium containing micro-fractures). Significant relationships between permeability, depth and the presence and orientation of faults have been identified; they account for a variation of up to 6 orders of magnitude in mean permeability measurements. This can be explained in part by the effect of the orientation of the current maximum principal stress directions within the BVG: however, it is likely that permeability is also dependent on the existence of fracture families, which cannot be effectively identified from the data currently available. These analyses have enabled considerable insight to be gained into the dominant features of flow within the BVG. The conceptual hydrogeological model derived here will have a significant effect on the outcome and reliability of future radionuclide transport predictions in the Sellafield area.

  16. Hydrogeophysics and remote sensing for the design of hydrogeological conceptual models in hard rocks - Sardón catchment (Spain)

    Science.gov (United States)

    Francés, Alain P.; Lubczynski, Maciek W.; Roy, Jean; Santos, Fernando A. M.; Mahmoudzadeh Ardekani, Mohammad R.

    2014-11-01

    Hard rock aquifers are highly heterogeneous and hydrogeologically complex. To contribute to the design of hydrogeological conceptual models of hard rock aquifers, we propose a multi-techniques methodology based on a downward approach that combines remote sensing (RS), non-invasive hydrogeophysics and hydrogeological field data acquisition. The proposed methodology is particularly suitable for data scarce areas. It was applied in the pilot research area of Sardón catchment (80 km2) located west of Salamanca (Spain). The area was selected because of hard-rock hydrogeology, semi-arid climate and scarcity of groundwater resources. The proposed methodology consisted of three main steps. First, we detected the main hydrogeological features at the catchment scale by processing: (i) a high resolution digital terrain model to map lineaments and to outline fault zones; and (ii) high-resolution, multispectral satellite QuickBird and WorldView-2 images to map the outcropping granite. Second, we characterized at the local scale the hydrogeological features identified at step one with: i) ground penetrating radar (GPR) to assess groundwater table depth complementing the available monitoring network data; ii) 2D electric resistivity tomography (ERT) and frequency domain electromagnetic (FDEM) to retrieve the hydrostratigraphy along selected survey transects; iii) magnetic resonance soundings (MRS) to retrieve the hydrostratigraphy and aquifer parameters at the selected survey sites. In the third step, we drilled 5 boreholes (25 to 48 m deep) and performed slug tests to verify the hydrogeophysical interpretation and to calibrate the MRS parameters. Finally, we compiled and integrated all acquired data to define the geometry and parameters of the Sardón aquifer at the catchment scale. In line with a general conceptual model of hard rock aquifers, we identified two main hydrostratigraphic layers: a saprolite layer and a fissured layer. Both layers were intersected and drained by

  17. Numerical Modeling of Shoreline Undulations

    DEFF Research Database (Denmark)

    Kærgaard, Kasper Hauberg

    model has been developed which describes the longshore sediment transport along arbitrarily shaped shorelines. The numerical model is based on a spectral wave model, a depth integrated flow model, a wave-phase resolving sediment transport description and a one-line shoreline model. First the theoretical...... of the feature and under predicts the migration speeds of the features. On the second shoreline, the shoreline model predicts undulations lengths which are longer than the observed undulations. Lastly the thesis considers field measurements of undulations of the bottom bathymetry along an otherwise straight...... length of the shoreline undulations is determined in the linear regime using a shoreline stability analysis based on the numerical model. The analysis shows that the length of the undulations in the linear regime depends on the incoming wave conditions and on the coastal profile. For larger waves...

  18. Efforts toward validation of a hydrogeological model of the Asse area

    International Nuclear Information System (INIS)

    Fein, E.; Klarr, K.; von Stempel, C.

    1995-01-01

    The Asse anticline (8 x 3 km) near Braunschweig (Germany) is part of the Subhercynian Basin and is characterized by a NW-SE orientation. In 1965, the GSF Research Center for Environment and Health acquired the former Asse salt mine on behalf of the FRG in order to carry out research and development work with a view of safe disposal of radioactive waste. To assess long term safety and predict groundwater flow nd radionuclide transport, an experimental program was carried out to validate hydrogeological models of the overburden of the Asse salt mine and to provide these with data. Five deep boreholes from 700 to 2250 m and 4 geological exploration shallow boreholes where drilled in the Asse area. Moreover, 19 piezometers and 27 exploration boreholes were sunk to perform pumping and tracer tests and yearly borehole loggings. In the end, about 50 boreholes and wells, 25 measuring weirs and about 70 creeks, drainage and springs were available to collect hydrological data and water samples. The different experiments and their evaluations as well as different hydrogeological models are presented and discussed. (J.S.). 9 refs., 7 figs

  19. Structural and geochemical techniques for the hydrogeological characterisation and stochastic modelling of fractured media

    International Nuclear Information System (INIS)

    Vela, A.; Elorza, F.J.; Florez, F.; Paredes, C.; Mazadiego, L.; Llamas, J.F.; Perez, E.; Vives, L.; Carrera, J.; Munoz, A.; De Vicente, G.; Casquet, C.

    1999-01-01

    Safety analysis of radioactive waste storage systems require fractured rock studies. The performance assessment studies of this type of problems include the development of radionuclide flow and transport models to predict the evolution of possible contaminants released from the repository to the biosphere. The methodology developed in the HIDROBAP project and some results obtained with its application in El Berrocal granite batholith are presented. It integrates modern tools belonging to different disciplines. A Discrete Fracture Network model (DFT) was selected to simulate the fractured medium and a 3D finite element flow and transport model that includes the inverse problem techniques has been coupled to the DFT model to simulate the water movement trough the fracture network system. Preliminary results show that this integrated methodology can be very useful for the hydrogeological characterisation of rock fractured media. (author)

  20. Death Valley regional ground-water flow system, Nevada and California -- hydrogeologic framework and transient ground-water flow model

    Science.gov (United States)

    Belcher, Wayne R.

    2004-01-01

    A numerical three-dimensional (3D) transient ground-water flow model of the Death Valley region was developed by the U.S. Geological Survey for the U.S. Department of Energy programs at the Nevada Test Site and at Yucca Mountain, Nevada. Decades of study of aspects of the ground-water flow system and previous less extensive ground-water flow models were incorporated and reevaluated together with new data to provide greater detail for the complex, digital model. A 3D digital hydrogeologic framework model (HFM) was developed from digital elevation models, geologic maps, borehole information, geologic and hydrogeologic cross sections, and other 3D models to represent the geometry of the hydrogeologic units (HGUs). Structural features, such as faults and fractures, that affect ground-water flow also were added. The HFM represents Precambrian and Paleozoic crystalline and sedimentary rocks, Mesozoic sedimentary rocks, Mesozoic to Cenozoic intrusive rocks, Cenozoic volcanic tuffs and lavas, and late Cenozoic sedimentary deposits of the Death Valley Regional Ground-Water Flow System (DVRFS) region in 27 HGUs. Information from a series of investigations was compiled to conceptualize and quantify hydrologic components of the ground-water flow system within the DVRFS model domain and to provide hydraulic-property and head-observation data used in the calibration of the transient-flow model. These studies reevaluated natural ground-water discharge occurring through evapotranspiration and spring flow; the history of ground-water pumping from 1913 through 1998; ground-water recharge simulated as net infiltration; model boundary inflows and outflows based on regional hydraulic gradients and water budgets of surrounding areas; hydraulic conductivity and its relation to depth; and water levels appropriate for regional simulation of prepumped and pumped conditions within the DVRFS model domain. Simulation results appropriate for the regional extent and scale of the model were

  1. Death Valley regional groundwater flow system, Nevada and California-Hydrogeologic framework and transient groundwater flow model

    Science.gov (United States)

    Belcher, Wayne R.; Sweetkind, Donald S.

    2010-01-01

    A numerical three-dimensional (3D) transient groundwater flow model of the Death Valley region was developed by the U.S. Geological Survey for the U.S. Department of Energy programs at the Nevada Test Site and at Yucca Mountain, Nevada. Decades of study of aspects of the groundwater flow system and previous less extensive groundwater flow models were incorporated and reevaluated together with new data to provide greater detail for the complex, digital model. A 3D digital hydrogeologic framework model (HFM) was developed from digital elevation models, geologic maps, borehole information, geologic and hydrogeologic cross sections, and other 3D models to represent the geometry of the hydrogeologic units (HGUs). Structural features, such as faults and fractures, that affect groundwater flow also were added. The HFM represents Precambrian and Paleozoic crystalline and sedimentary rocks, Mesozoic sedimentary rocks, Mesozoic to Cenozoic intrusive rocks, Cenozoic volcanic tuffs and lavas, and late Cenozoic sedimentary deposits of the Death Valley regional groundwater flow system (DVRFS) region in 27 HGUs. Information from a series of investigations was compiled to conceptualize and quantify hydrologic components of the groundwater flow system within the DVRFS model domain and to provide hydraulic-property and head-observation data used in the calibration of the transient-flow model. These studies reevaluated natural groundwater discharge occurring through evapotranspiration (ET) and spring flow; the history of groundwater pumping from 1913 through 1998; groundwater recharge simulated as net infiltration; model boundary inflows and outflows based on regional hydraulic gradients and water budgets of surrounding areas; hydraulic conductivity and its relation to depth; and water levels appropriate for regional simulation of prepumped and pumped conditions within the DVRFS model domain. Simulation results appropriate for the regional extent and scale of the model were provided

  2. Near-surface hydrogeological model of Laxemar. Open repository - Laxemar 1.2

    Energy Technology Data Exchange (ETDEWEB)

    Bosson, Emma

    2006-07-15

    This report presents the methodology and the results from the modelling of an open final repository for spent nuclear fuel in Laxemar. Thus, the present work analyses the hydrological effects of the planned repository during the construction and operational phases when it is open, i.e. air-filled, and hence may cause a disturbance of the hydrological conditions in the surroundings. The numerical modelling is based on the conceptual and descriptive model presented in the version 1.2 Site Descriptive Model (SDM) for Laxemar. The modelling was divided into three steps. The first step was to update the L1.2 version model for hydrology and near surface hydrogeology, the main updates were related to the hydraulic properties of the bedrock and the size of the model area. The next step was to describe the conditions for the introductory construction by implementing the access tunnel and shafts to the model. The third step aimed at describing the consequences on the surface hydrology caused by an open repository. A sensitivity analysis that aimed to investigate the sensitivity of the model to the properties of the upper bedrock and the properties in the interface between the Quaternary deposits and the bedrock was performed as a part of steps two and three. The model covers an area of 19 km{sup 2}. In the Quaternary deposits, the surface water divides are assumed to coincide with the groundwater divides, thus a no-flow boundary condition is used at the horizontal boundaries. The transient top boundary condition uses meteorological data gathered at a local SKB station at Aespoe during 2004. The bottom boundary condition and the horizontal boundary condition in the bedrock is a steady state head boundary condition taken from the open repository modelling of the bedrock performed as a parallel activity with the modelling tool DarcyTools. The vertical extent of the model is from the ground surface to 150 m below sea level. Since the repository will be built at 450 m below sea

  3. Hydrogeology baseline study Aurora Mine

    International Nuclear Information System (INIS)

    1996-01-01

    A baseline hydrogeologic study was conducted in the area of Syncrude's proposed Aurora Mine in order to develop a conceptual regional hydrogeologic model for the area that could be used to understand groundwater flow conditions. Geologic information was obtained from over 2,000 coreholes and from data obtained between 1980 and 1996 regarding water level for the basal aquifer. A 3-D numerical groundwater flow model was developed to provide quantitative estimates of the potential environmental impacts of the proposed mining operations on the groundwater flow system. The information was presented in the context of a regional study area which encompassed much of the Athabasca Oil Sands Region, and a local study area which was defined by the lowlands of the Muskeg River Basin. Characteristics of the topography, hydrology, climate, geology, and hydrogeology of the region are described. The conclusion is that groundwater flow in the aquifer occurs mostly in a westerly direction beneath the Aurora Mine towards its inferred discharge location along the Athabasca River. Baseflow in the Muskeg River is mostly related to discharge from shallow surficial aquifers. Water in the river under baseflow conditions was fresh, of calcium-carbonate type, with very little indication of mineralization associated with deeper groundwater in the Aurora Mine area. 44 refs., 5 tabs., 31 figs

  4. Hydrogeological bedrock inferred from electrical resistivity model in Taichung Basin, Taiwan

    Science.gov (United States)

    Chiang, C. W.; Chang, P. Y.; Chang, L. C.

    2015-12-01

    The four-year project of the study of groundwater hydrogeology and recharge model was indicated by Central Geological Survey, MOEA, Taiwan (R.O.C.) to evaluate recharge groundwater areas in Taiwan where included Taipei, Taichung Basins, Lanyang and Chianan Plains. The groundwater recharge models of Lanyang Plain and Taipei Basin have successfully been estimated in two years ago (2013-2014). The third year of the project integrates with geophysical, geochemistry, and hydrogeology models to estimate the groundwater recharge model in Taichung Basin region. Taichung Basin is mainly covered by Pre-Pleistocene of thick gravel, sandy and muddy sediment rocks within a joint alluvial fan, whereas the depth of the hydrological bedrock remains uncertain. Two electrical resistivity geophysical tools were carried out utilizing direct current resistivity and audio-magnetotelluric (AMT) explorations, which could ideally provide the depth resolutions from shallow to depth for evaluating the groundwater resources. The study has carried out 21 AMT stations in the southern Taichung Basin in order to delineate hydrological bedrock in the region. All the AMT stations were deployed about 24 hours and processed with remote reference technique to reduce culture noises. The quality of most stations shows acceptable in the area which two stations were excluded due to near-field source effect in the southwestern basin. The best depth resolution is identified in 500 meters for the model. The preliminary result shows that the depths of the bedrock gradually changes from southern ~20 m toward to ~400 m in central, and eastern ~20 m to 180 m in the western basin inferred from the AMT model. The investigation shows that AMT method could be a useful geophysical tool to enhance the groundwater recharge model estimation without dense loggings in the region.

  5. Hydrogeological boundary settings in SR 97. Uncertainties in regional boundary settings and transfer of boundary conditions to site-scale models

    International Nuclear Information System (INIS)

    Follin, S.

    1999-06-01

    The SR 97 project presents a performance assessment (PA) of the overall safety of a hypothetical deep repository at three sites in Sweden arbitrarily named Aberg, Beberg and Ceberg. One component of this PA assesses the uncertainties in the hydrogeological modelling. This study focuses on uncertainties in boundary settings (size of model domain and boundary conditions) in the regional and site-scale hydrogeological modelling of the three sites used to simulating the possible transport of radionuclides from the emplacement waste packages through the host rock to the accessible environment. Model uncertainties associated with, for instance, parameter heterogeneity and structural interpretations are addressed in other studies. This study concludes that the regional modelling of the SR 97 project addresses uncertainties in the choice of boundary conditions and size of model domain differently at each site, although the overall handling is acceptable and in accordance with common modelling practice. For example, the treatment of uncertainties with regard to the ongoing post-glacial flushing of the Baltic Shield is creditably addressed although not exhaustive from a modelling point of view. A significant contribution of the performed modelling is the study of nested numerical models, i.e., the numerical interplay between regional and site-scale numerical models. In the site-scale modelling great efforts are made to address problems associated with (i) the telescopic mesh refinement (TMR) technique with regard to the stochastic continuum approach, and (ii) the transfer of boundary conditions between variable-density flow systems and flow systems that are constrained to treat uniform density flow. This study concludes that the efforts made to handle these problems are acceptable with regards to the objectives of the SR 97 project

  6. Impact of river stage prediction methods on stream-aquifer exchanges in a hydro(geo)logical model at the regional scale

    Science.gov (United States)

    Saleh, F.; Flipo, N.; de Fouquet, C.

    2012-04-01

    The main objective of this study is to provide a realistic simulation of river stage in regional river networks in order to improve the quantification of stream-aquifer exchanges and better assess the associated aquifer responses that are often impacted by the magnitude and the frequency of the river stage fluctuations. The study focuses on the Oise basin (17 000 km2, part of the 65 000 km2 Seine basin in Northern France) where stream-aquifer exchanges cannot be assessed directly by experimental methods. Nowadays numerical methods are the most appropriate approaches for assessing stream-aquifer exchanges at this scale. A regional distributed process-based hydro(geo)logical model, Eau-Dyssée, is used, which aims at the integrated modeling of the hydrosystem to manage the various elements involved in the quantitative and qualitative aspects of water resources. Eau-Dyssée simulates pseudo 3D flow in aquifer systems solving the diffusivity equation with a finite difference numerical scheme. River flow is simulated with a Muskingum model. In addition to the in-stream discharge, a river stage estimate is needed to calculate the water exchange at the stream-aquifer interface using the Darcy law. Three methods for assessing in-stream river stages are explored to determine the most appropriate representation at regional scale over 25 years (1980-2005). The first method consists in defining rating curves for each cell of a 1D Saint-Venant hydraulic model. The second method consists in interpolating observed rating curves (at gauging stations) onto the river cells of the hydro(geo)logical model. The interpolation technique is based on geostatistics. The last method assesses river stage using Manning equation with a simplified rectangular cross-section (water depth equals the hydraulic radius). Compared to observations, the geostatistical and the Manning methodologies lead to slightly less accurate (but still acceptable) results offering a low computational cost opportunity

  7. 3D hydrogeological model of the Lower Yarmouk Gorge, Jordan Rift Valley

    Science.gov (United States)

    Magri, Fabien; Inbar, Nimrod; Möller, Peter; Raggad, Marwan; Rödiger, Tino; Rosenthal, Eliahu; Shentsis, Izabela; Tzoufka, Kalliopi; Siebert, Christian

    2017-04-01

    The Lower Yarmouk Gorge (LYG) lies on the eastern margin of the lower Jordan Rift Valley (JRV), bounded to the south by the Ajlun and to the north by the Golan Heights. It allows the outflow of the Yarmouk drainage basin and flow into the Jordan River, a few kilometers south of Lake Tiberias. The main aquifer system of the LYG is built mostly of Cretaceous sandstones and carbonates confined by Maastrichtian aquiclude. Fissures allow hydraulic connections between the major water-bearing formations from Quaternary to Upper Cretaceous age. It is supposed that the gorge acts as the mixing zone of two crossing flow pathways: N-S from the Hermon Mountains and from the Ajlun Dome, and E-W from Jebel al Arab Mountain in Syria (also known as Huran Plateau or Yarmouk drainage basin). As a result, several springs can be found within the gorge. These are characterized by widespread temperatures (20 - 60 °C) which indicate that, beside the complex regional flow, also ascending thermal waters control the hydrologic behavior of the LYG. Previous simulations based on a conceptual simplified 3D model (Magri et al., 2016) showed that crossing flow paths result from the coexistence of convection, that can develop for example along NE-SW oriented faults within the gorge or in permeable aquifers below Maastrichtian aquiclude, and additional flow fields that are induced by the N-S topographic gradients. Here we present the first 3D hydrogeological model of the entire LYG that includes structural features based on actual logs and interpreted seismic lines from both Israeli and Jordanian territories. The model distinguishes seven units from upper Eocene to the Lower Triassic, accounting for major aquifers, aquicludes and deep-cutting faults. Recharges are implemented based on the numerical representation developed by Shentsis (1990) that considers relationships between mean annual rain and topographic elevation. The model reveals that topography-driven N-S and E-W flows strongly control

  8. Sensitivity analysis and development of calibration methodology for near-surface hydrogeology model of Laxemar

    International Nuclear Information System (INIS)

    Aneljung, Maria; Sassner, Mona; Gustafsson, Lars-Goeran

    2007-11-01

    This report describes modelling where the hydrological modelling system MIKE SHE has been used to describe surface hydrology, near-surface hydrogeology, advective transport mechanisms, and the contact between groundwater and surface water within the SKB site investigation area at Laxemar. In the MIKE SHE system, surface water flow is described with the one-dimensional modelling tool MIKE 11, which is fully and dynamically integrated with the groundwater flow module in MIKE SHE. In early 2008, a supplementary data set will be available and a process of updating, rebuilding and calibrating the MIKE SHE model based on this data set will start. Before the calibration on the new data begins, it is important to gather as much knowledge as possible on calibration methods, and to identify critical calibration parameters and areas within the model that require special attention. In this project, the MIKE SHE model has been further developed. The model area has been extended, and the present model also includes an updated bedrock model and a more detailed description of the surface stream network. The numerical model has been updated and optimized, especially regarding the modelling of evapotranspiration and the unsaturated zone, and the coupling between the surface stream network in MIKE 11 and the overland flow in MIKE SHE. An initial calibration has been made and a base case has been defined and evaluated. In connection with the calibration, the most important changes made in the model were the following: The evapotranspiration was reduced. The infiltration capacity was reduced. The hydraulic conductivities of the Quaternary deposits in the water-saturated part of the subsurface were reduced. Data from one surface water level monitoring station, four surface water discharge monitoring stations and 43 groundwater level monitoring stations (SSM series boreholes) have been used to evaluate and calibrate the model. The base case simulations showed a reasonable agreement

  9. Hydrogeological study

    International Nuclear Information System (INIS)

    Massa, E.; Carrion, R.

    1987-01-01

    This work refers to the hydrogeological study about underground water to domestic uses. It was required by Artigas intendence of Uruguay, in the rural school 10, located belongs to the Chiflero zone around the capital of the Artigas Province.

  10. Numerical models for differential problems

    CERN Document Server

    Quarteroni, Alfio

    2017-01-01

    In this text, we introduce the basic concepts for the numerical modelling of partial differential equations. We consider the classical elliptic, parabolic and hyperbolic linear equations, but also the diffusion, transport, and Navier-Stokes equations, as well as equations representing conservation laws, saddle-point problems and optimal control problems. Furthermore, we provide numerous physical examples which underline such equations. We then analyze numerical solution methods based on finite elements, finite differences, finite volumes, spectral methods and domain decomposition methods, and reduced basis methods. In particular, we discuss the algorithmic and computer implementation aspects and provide a number of easy-to-use programs. The text does not require any previous advanced mathematical knowledge of partial differential equations: the absolutely essential concepts are reported in a preliminary chapter. It is therefore suitable for students of bachelor and master courses in scientific disciplines, an...

  11. Sensitivity analysis and development of calibration methodology for near-surface hydrogeology model of Laxemar

    Energy Technology Data Exchange (ETDEWEB)

    Aneljung, Maria; Sassner, Mona; Gustafsson, Lars-Goeran (DHI Sverige AB, Lilla Bommen 1, SE-411 04 Goeteborg (Sweden))

    2007-11-15

    This report describes modelling where the hydrological modelling system MIKE SHE has been used to describe surface hydrology, near-surface hydrogeology, advective transport mechanisms, and the contact between groundwater and surface water within the SKB site investigation area at Laxemar. In the MIKE SHE system, surface water flow is described with the one-dimensional modelling tool MIKE 11, which is fully and dynamically integrated with the groundwater flow module in MIKE SHE. In early 2008, a supplementary data set will be available and a process of updating, rebuilding and calibrating the MIKE SHE model based on this data set will start. Before the calibration on the new data begins, it is important to gather as much knowledge as possible on calibration methods, and to identify critical calibration parameters and areas within the model that require special attention. In this project, the MIKE SHE model has been further developed. The model area has been extended, and the present model also includes an updated bedrock model and a more detailed description of the surface stream network. The numerical model has been updated and optimized, especially regarding the modelling of evapotranspiration and the unsaturated zone, and the coupling between the surface stream network in MIKE 11 and the overland flow in MIKE SHE. An initial calibration has been made and a base case has been defined and evaluated. In connection with the calibration, the most important changes made in the model were the following: The evapotranspiration was reduced. The infiltration capacity was reduced. The hydraulic conductivities of the Quaternary deposits in the water-saturated part of the subsurface were reduced. Data from one surface water level monitoring station, four surface water discharge monitoring stations and 43 groundwater level monitoring stations (SSM series boreholes) have been used to evaluate and calibrate the model. The base case simulations showed a reasonable agreement

  12. Numerical simulation of Higgs models

    International Nuclear Information System (INIS)

    Jaster, A.

    1995-10-01

    The SU(2) Higgs and the Schwinger model on the lattice were analysed. Numerical simulations of the SU(2) Higgs model were performed to study the finite temperature electroweak phase transition. With the help of the multicanonical method the distribution of an order parameter at the phase transition point was measured. This was used to obtain the order of the phase transition and the value of the interface tension with the histogram method. Numerical simulations were also performed at zero temperature to perform renormalization. The measured values for the Wilson loops were used to determine the static potential and from this the renormalized gauge coupling. The Schwinger model was simulated at different gauge couplings to analyse the properties of the Kaplan-Shamir fermions. The prediction that the mass parameter gets only multiplicative renormalization was tested and verified. (orig.)

  13. Hydrogeologic modelling in support of a proposed Deep Geologic Repository in Canada for low and intermediate level radioactive waste

    Energy Technology Data Exchange (ETDEWEB)

    Sykes, J.F.; Normani, S.D.; Yin, Y. [Waterloo Univ., ON (Canada). Dept. of Civil and Environmental Engineering; Sykes, E.A.; Jensen, M.R. [Nuclear Waste Management Organization, Toronto, ON (Canada)

    2009-07-01

    Ontario Power Generation (OPG) has proposed the construction of a Deep Geologic Repository (DGR) for low and intermediate level radioactive waste at the Bruce site on the shore of Lake Huron near Tiverton, Ontario. The DGR is to be excavated at a depth of about 680 m within argillaceous limestones of Ordovician age. A saturated regional-scale and site-scale numerical modelling study has been completed in order to evaluate the safety of storing radioactive waste at the site and to better understand the geochemistry and hydrogeology of the formations surrounding the proposed DGR. This paper reported on the regional-scale base-case modelling and analysis of the measured pressure profile in deep boreholes at the DGR site. The numerical modelling study provided a framework to investigate the groundwater flow system as it relates to, and potentially affects, the safety and long-term performance of the DGR. A saturated groundwater flow model was also developed using FRAC3DVS-OPG. The objective of regional-scale groundwater modelling of the Paleozoic sedimentary sequence underlying southwestern Ontario was to provide a basis for the assembly and integration of site-specific geoscientific data and to explain the influence of parameter and scenario uncertainty on predicted long-term geosphere barrier performance. The base-case analysis showed that solute transport in the Ordovician and lower Silurian is diffusion dominant. For the base-case parameters, the estimated mean life expectancy for the proposed DGR is more than 8 million years. The possible presence of a gas phase in the rock between the Cambrian and the Niagaran was not considered in the analyses of this paper. 9 refs., 2 tabs., 10 figs.

  14. Stepwise hydrogeological modeling and groundwater flow analysis on site scale (The former part of the step 3)

    International Nuclear Information System (INIS)

    Onoe, Hironori; Saegusa, Hiromitsu; Endo, Yoshinobu

    2005-07-01

    One of the main goals of the Mizunami Underground Research Laboratory Project is to establish comprehensive techniques for investigation, analysis, and assessment of the deep geological environment. To achieve this goal, a variety of investigations are being conducted using an iterative approach. In this study, hydrogeological modeling and groundwater flow analyses have been carried out using the data from surface-based investigations at the former part of Step 3 (deep borehole investigations without vertical seismic profiling investigations), in order to synthesize the investigation results, to evaluate the uncertainty of the hydrogeological model, and to specify items for further investigation. The results of this study are summarized as follows: 1) The uncertainty of hydrogeological model of the site scale is decreased as stepwise research; 2) Borehole investigations combined with hydraulic monitoring are useful for decreasing the uncertainty of hydrogeological model; The main items specified for further investigations are summarized as follows: 1) Trend, length, and hydraulic parameters of faults confirmed in the MIU construction site; 2) Shape of boundary of geological layer, and hydraulic parameters of rock; 3) Hydraulic head distribution of deep underground. (author)

  15. Integrating advanced 3D Mapping into Improved Hydrogeologic Frameworks, a Future path for Groundwater Modeling? Results from Western Nebraska

    Science.gov (United States)

    Cannia, J. C.; Abraham, J. D.; Peterson, S. M.; Sibray, S. S.

    2012-12-01

    The U.S. Geological Survey and its partners have collaborated to provide an innovative, advanced 3 dimensional hydrogeologic framework which was used in a groundwater model designed to test water management scenarios. Principal aquifers for the area mostly consist of Quaternary alluvium and Tertiary-age fluvial sediments which are heavily used for irrigation, municipal and environmental uses. This strategy used airborne electromagnetic (AEM) surveys, validated through sensitivity analysis of geophysical and geological ground truth to provide new geologic interpretation to characterize the hydrogeologic framework in the area. The base of aquifer created through this work leads to new interpretations of saturated thickness and groundwater connectivity to the surface water system. The current version of the groundwater model which uses the advanced hydrogeologic framework shows a distinct change in flow path orientation, timing and amount of base flow to the streams of the area. Ongoing efforts for development of the hydrogeologic framework development include subdivision of the aquifers into new hydrostratigraphic units based on analysis of geophysical and lithologic characteristics which will be incorporated into future groundwater models. The hydrostratigraphic units are further enhanced by Nuclear Magnetic Resonance (NMR) measurements to characterize aquifers. NMR measures the free water in the aquifer in situ allowing for a determination of hydraulic conductivity. NMR hydraulic conductivity values will be mapped to the hydrostratigraphic units, which in turn are incorporated into the latest versions of the groundwater model. The addition of innovative, advanced 3 dimensional hydrogeologic frameworks, which incorporates AEM and NMR, for groundwater modeling, has a definite advantage over traditional frameworks. These groundwater models represent the natural system at a level of reality not achievable by other methods, which lead to greater confidence in the

  16. Hydrogeological DFN modelling using structural and hydraulic data from KLX04. Preliminary site description Laxemar subarea - version 1.2

    Energy Technology Data Exchange (ETDEWEB)

    Follin, Sven [SF GeoLogic AB, Taeby (Sweden); Stigsson, Martin [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Svensson, Urban [Computer-aided Fluid Engineering AB, Norrkoeping (Sweden)

    2006-04-15

    SKB is conducting site investigations for a high-level nuclear waste repository in fractured crystalline rocks at two coastal areas in Sweden. The two candidate areas are named Forsmark and Simpevarp. The site characterisation work is divided into two phases, an initial site investigation phase (ISI) and a complete site investigation phase (CSI). The results of the ISI phase are used as a basis for deciding on the subsequent CSI phase. On the basis of the CSI investigations a decision is made as to whether detailed characterisation will be performed (including sinking of a shaft). An integrated component in the site characterisation work is the development of site descriptive models. These comprise basic models in three dimensions with an accompanying text description. Central in the modelling work is the geological model which provides the geometrical context in terms of a model of deformation zones and the less fractured rock mass between the zones. Using the geological and geometrical description models as a basis, descriptive models for other disciplines (surface ecosystems, hydrogeology, hydrogeochemistry, rock mechanics, thermal properties and transport properties) will be developed. Great care is taken to arrive at a general consistency in the description of the various models and assessment of uncertainty and possible needs of alternative models. The main objective of this study is to support the development of a hydrogeological DFN model (Discrete Fracture Network) for the Preliminary Site Description of the Laxemar area on a regional-scale (SDM version L1.2). A more specific objective of this study is to assess the propagation of uncertainties in the geological DFN modelling reported for L1.2 into the groundwater flow modelling. An improved understanding is necessary in order to gain credibility for the Site Description in general and the hydrogeological description in particular. The latter will serve as a basis for describing the present

  17. Hydrogeological DFN modelling using structural and hydraulic data from KLX04. Preliminary site description Laxemar subarea - version 1.2

    International Nuclear Information System (INIS)

    Follin, Sven; Stigsson, Martin; Svensson, Urban

    2006-04-01

    SKB is conducting site investigations for a high-level nuclear waste repository in fractured crystalline rocks at two coastal areas in Sweden. The two candidate areas are named Forsmark and Simpevarp. The site characterisation work is divided into two phases, an initial site investigation phase (ISI) and a complete site investigation phase (CSI). The results of the ISI phase are used as a basis for deciding on the subsequent CSI phase. On the basis of the CSI investigations a decision is made as to whether detailed characterisation will be performed (including sinking of a shaft). An integrated component in the site characterisation work is the development of site descriptive models. These comprise basic models in three dimensions with an accompanying text description. Central in the modelling work is the geological model which provides the geometrical context in terms of a model of deformation zones and the less fractured rock mass between the zones. Using the geological and geometrical description models as a basis, descriptive models for other disciplines (surface ecosystems, hydrogeology, hydrogeochemistry, rock mechanics, thermal properties and transport properties) will be developed. Great care is taken to arrive at a general consistency in the description of the various models and assessment of uncertainty and possible needs of alternative models. The main objective of this study is to support the development of a hydrogeological DFN model (Discrete Fracture Network) for the Preliminary Site Description of the Laxemar area on a regional-scale (SDM version L1.2). A more specific objective of this study is to assess the propagation of uncertainties in the geological DFN modelling reported for L1.2 into the groundwater flow modelling. An improved understanding is necessary in order to gain credibility for the Site Description in general and the hydrogeological description in particular. The latter will serve as a basis for describing the present

  18. Assessment of site-scale hydrogeological modelling possibilities in crystalline hard rock for safety appraisal

    Energy Technology Data Exchange (ETDEWEB)

    Geier, J. [Cleanwater Hardrock Consulting, Corvallis, OR (United States); Luukkonen, A.

    2012-09-15

    This review describes the state-of-the-art in hydrogeological modelling for safety-case studies related to spent-fuel repositories in crystalline hard rock, focusing on issues of relevance for the KBS-3 disposal concept in Nordic environments. The review includes a survey of model capabilities and assumptions regarding groundwater flow processes, geological and excavation-related features, and boundary conditions for temperate, periglacial, and glacial climates. Modelling approaches are compared for research sites including the Stripa mine (Sweden), the Grimsel Test Site (Switzerland), the Whiteshell Underground Research Laboratory (Canada), the Aspo Hard Rock Laboratory and Simpevarp-Laxemar site (Sweden), the Forsmark site (Sweden), the Waste Isolation Pilot Plant site (USA), and Olkiluoto (Finland). Current hydrogeological models allow realistic representations, but are limited by availability of data to constrain their properties. Examples of calibrations of stochastic representations of heterogeneity are still scarce. Integrated models that couple flow and non-reactive transport are now well established, particularly those based on continuum representations. Models that include reactive transport are still mainly in the realm of research tools. Thus far, no single software tool allows fully coupled treatment of all relevant thermal, hydraulic, mechanical, and chemical transport processes in the bedrock, together with climate-related physical processes at the ground surface, and with explicit treatment of bedrock heterogeneity. Hence practical applications require combinations of models based on different simplifications. Key improvements can be expected in treatment of the unsaturated zone, simulation of heterogeneous infiltration at the surface, and hydromechanical coupling. Significant advances have already been made in the amounts and types of data that can be used in site-scale models, including large datasets to define topography and other surface

  19. Plasma modelling and numerical simulation

    International Nuclear Information System (INIS)

    Van Dijk, J; Kroesen, G M W; Bogaerts, A

    2009-01-01

    Plasma modelling is an exciting subject in which virtually all physical disciplines are represented. Plasma models combine the electromagnetic, statistical and fluid dynamical theories that have their roots in the 19th century with the modern insights concerning the structure of matter that were developed throughout the 20th century. The present cluster issue consists of 20 invited contributions, which are representative of the state of the art in plasma modelling and numerical simulation. These contributions provide an in-depth discussion of the major theories and modelling and simulation strategies, and their applications to contemporary plasma-based technologies. In this editorial review, we introduce and complement those papers by providing a bird's eye perspective on plasma modelling and discussing the historical context in which it has surfaced. (editorial review)

  20. A revised conceptual hydrogeologic model of a crystalline rock environment, Whiteshell research area, southeastern Manitoba, Canada

    International Nuclear Information System (INIS)

    Stevenson, D.R.; Brown, A.; Davison, C.C.; Gascoyne, M.; McGregor, R.G.; Ophori, D.U.; Scheier, N.W.; Stanchell, F.; Thorne, G.A.; Tomsons, D.K.

    1996-04-01

    A revised conceptual hydrogeologic model of regional groundwater flow in the crystalline rocks of the Whiteshell Research Area (WRA) has been developed by a team of AECL geoscientists. The revised model updates an earlier model developed in 1985, and has a much broader database. This database was compiled from Landsat and airborne radar images, geophysical surveys and surface mapping, and from analyses of fracture logs, hydraulic tests and water samples collected from a network of deep boreholes drilled across the WRA. The boundaries of the revised conceptual model were selected to coincide with the natural hydraulic boundaries assumed for the regional groundwater flow systems in the WRA. The upper and lower boundaries are the water table and a horizontal plane 4 km below ground surface. For modelling purposes the rocks below 4 km are considered to be impermeable. The rocks of the modelled region were divided on the basis of fracture characteristics into three categories: fractured zones (FZs); moderately fractured rock (MFR); and sparsely fractured rock (SFR). The FZs are regions of intensely fractured rock. Seventy-six FZs were selected to form the fault framework within the revised conceptual model. The physical rock/water properties of the FZs, MFR and SFR were selected by analysis of field data from hydraulic and tracer tests, laboratory test data and water quality data. These properties were used to define a mathematical groundwater flow model of the WRA using AECL's MOTIF finite element code (Ophori et al. 1995, 1996). (author). 29 refs., 4 tabs., 12 figs

  1. Numerical model of thyroid counter

    Directory of Open Access Journals (Sweden)

    Szuchta Maciej

    2016-03-01

    Full Text Available The aim of this study was to develop a numerical model of spectrometric thyroid counter, which is used for the measurements of internal contamination by in vivo method. The modeled detector is used for a routine internal exposure monitoring procedure in the Radiation Protection Measurements Laboratory of National Centre for Nuclear Research (NCBJ. This procedure may also be used for monitoring of occupationally exposed nuclear medicine personnel. The developed model was prepared using Monte Carlo code FLUKA 2011 ver. 2b.6 Apr-14 and FLAIR ver. 1.2-5 interface. It contains a scintillation NaI(Tl detector, the collimator and the thyroid water phantom with a reference source of iodine 131I. The geometry of the model was designed and a gamma energy spectrum of iodine 131I deposited in the detector was calculated.

  2. Comprehensive numerical modelling of tokamaks

    International Nuclear Information System (INIS)

    Cohen, R.H.; Cohen, B.I.; Dubois, P.F.

    1991-01-01

    We outline a plan for the development of a comprehensive numerical model of tokamaks. The model would consist of a suite of independent, communicating packages describing the various aspects of tokamak performance (core and edge transport coefficients and profiles, heating, fueling, magnetic configuration, etc.) as well as extensive diagnostics. These codes, which may run on different computers, would be flexibly linked by a user-friendly shell which would allow run-time specification of packages and generation of pre- and post-processing functions, including workstation-based visualization of output. One package in particular, the calculation of core transport coefficients via gyrokinetic particle simulation, will become practical on the scale required for comprehensive modelling only with the advent of teraFLOP computers. Incremental effort at LLNL would be focused on gyrokinetic simulation and development of the shell

  3. A comparison of results from groundwater flow modelling for two conceptual hydrogeological models for the Konrad site

    International Nuclear Information System (INIS)

    Arens, G.; Fein, E.; Storck, R.

    1991-01-01

    Radioactive wastes with negligible heat production are planned to be disposed of into a deep iron ore formation at the Konrad site. This repository will be bedded in a low permeable formation called Oxfordian in a depth of 800 - 1300 m below the surface. The host formation is largely covered with clay of a few hundred meters thickness. The hydrogeological model area has an extension of 14 km in the west-east and 47 km in the north-south direction. The geological formations within the model area are disturbed by several fractured zones with a vertical extension of several hundred meters intersecting different horizontal layers. Due to this fact two hydrogeological models have been developed: The first one handles the fractured zones by globally increased permeabilities of the geological formations. The second handles the fractured zones by locally increased permeabilities, leaving the permeabilities of undisturbed areas unchanged. For both models, groundwater flow calculations have been carried out including parameter variations of permeability values. The results of the calculations are presented as flow paths which are compared for both models. Computer code used: SWIFT. 1 fig., 3 tabs., 3 refs

  4. Numerical modeling of foam flows

    International Nuclear Information System (INIS)

    Cheddadi, Ibrahim

    2010-01-01

    Liquid foam flows are involved in numerous applications, e.g. food and cosmetics industries, oil extraction, nuclear decontamination. Moreover, their study leads to fundamental knowledge: as it is easier to manipulate and analyse, foam is used as a model material to understand the flow of emulsions, polymers, pastes, or cell aggregates, all of which display both solid and liquid behaviour. Systematic experiments performed by Francois Graner et al. provide precise data that emphasize the non Newtonian properties of the foam. Meanwhile, Pierre Saramito proposed a visco-elasto-plastic continuous tensorial model, akin to predict the behaviour of the foam. The goal of this thesis is to understand this complex behaviour, using these two elements. We have built and validated a resolution algorithm based on a bidimensional finite elements methods. The numerical solutions are in excellent agreement with the spatial distribution of all measured quantities, and confirm the predictive capabilities of the model. The dominant parameters have been identified and we evidenced the fact that the viscous, elastic, and plastic contributions to the flow have to be treated simultaneously in a tensorial formalism. We provide a substantial contribution to the understanding of foams and open the path to realistic simulations of complex VEP flows for industrial applications. (author)

  5. Hydrogeological modelling for assessment of radionuclide release scenarios for the repository system 2012

    Energy Technology Data Exchange (ETDEWEB)

    Hartley, L.; Hoek, J.; Swan, D.; Appleyard, P.; Baxter, S.; Roberts, D.; Simpson, T. [AMEC (United Kingdom)

    2013-07-15

    Posiva Oy is responsible for implementing the programme for geological disposal of spent nuclear fuel produced by its owners Teollisuuden Voima Oyj (TVO) and Fortum Power and Heat Oy in Finland. Olkiluoto in Eurajoki has been selected as the primary site for the repository, subject to further detailed investigation which is currently focused on the construction of an underground rock characterisation and research facility (the ONKALO). An essential part of the assessment of long-term safety of a repository is the analysis of groundwater flow since it is the only means of transport of radionuclides to the biosphere (besides human intrusion). The analysis of long-term safety for a KBS-3 concept requires as input a description of details of the groundwater flow around and through components of the engineered barrier system as well as details of the groundwater pathway to the biosphere during the current temperate climate period, as well as indications of behaviour under future climate periods such as glacial conditions. This report describes the groundwater flow modelling study performed to provide some of the necessary inputs required by Safety Assessment (i.e. radionuclide transport analysis). Underlying this study is the understanding of the site developed during the site investigations as summarised in the site descriptive model (SDM), and in particular the description of Olkiluoto Hydrogeological DFN model (Hydro-DFN). The main focus of this study is the temperate climate period, i.e. the evolution over the next 10,000 years, but the hydrogeological situation under various glacial climate conditions is also evaluated. Primary outputs of the study are repository performance measures relating to: the distributions of groundwater flow around the deposition holes; deposition tunnels and through the EDZ; flow-related transport resistance along groundwater pathways from the repository to the surface; and their the exit locations. Other analyses consider the

  6. Hydrogeological modelling for assessment of radionuclide release scenarios for the repository system 2012

    International Nuclear Information System (INIS)

    Hartley, L.; Hoek, J.; Swan, D.; Appleyard, P.; Baxter, S.; Roberts, D.; Simpson, T.

    2013-07-01

    Posiva Oy is responsible for implementing the programme for geological disposal of spent nuclear fuel produced by its owners Teollisuuden Voima Oyj (TVO) and Fortum Power and Heat Oy in Finland. Olkiluoto in Eurajoki has been selected as the primary site for the repository, subject to further detailed investigation which is currently focused on the construction of an underground rock characterisation and research facility (the ONKALO). An essential part of the assessment of long-term safety of a repository is the analysis of groundwater flow since it is the only means of transport of radionuclides to the biosphere (besides human intrusion). The analysis of long-term safety for a KBS-3 concept requires as input a description of details of the groundwater flow around and through components of the engineered barrier system as well as details of the groundwater pathway to the biosphere during the current temperate climate period, as well as indications of behaviour under future climate periods such as glacial conditions. This report describes the groundwater flow modelling study performed to provide some of the necessary inputs required by Safety Assessment (i.e. radionuclide transport analysis). Underlying this study is the understanding of the site developed during the site investigations as summarised in the site descriptive model (SDM), and in particular the description of Olkiluoto Hydrogeological DFN model (Hydro-DFN). The main focus of this study is the temperate climate period, i.e. the evolution over the next 10,000 years, but the hydrogeological situation under various glacial climate conditions is also evaluated. Primary outputs of the study are repository performance measures relating to: the distributions of groundwater flow around the deposition holes; deposition tunnels and through the EDZ; flow-related transport resistance along groundwater pathways from the repository to the surface; and their the exit locations. Other analyses consider the

  7. Geological investigations contributing to the hydrogeological conceptual model in the Meuse/Haute-Marne area, Eastern France

    International Nuclear Information System (INIS)

    Rocher, M.; De Hoyos, A.; Hibsch, C.; Viennot, P.

    2010-01-01

    Callovian-Oxfordian (COX) indurated clay formation is currently studied by Andra in the 'Meuse/Haute-Marne' (MHM) area for hosting a potential repository of high level, long-lived radioactive waste. IRSN is conducting studies in support of the safety evaluation of the geological disposal programme developed by Andra. IRSN, in collaboration with the Paris School of Mines, develops conceptual and numerical models of the underground water flows throughout the Paris sedimentary basin. The calibrated numerical model correctly represents the hydraulic heads and water salinities collected throughout the basin. At the MHM scale however, several flow patterns can still reproduce the measured heads, some of them assuming specific flow pathways along regional tectonic trends. Considering or not such tectonic trends in the model has however an impact on the estimated radionuclide transfer times to the outlets. Even though most ANDRA and IRSN geochemical analyses suggest a dominant diffusive transport across the COX between the underlying Dogger and overlying Oxfordian aquifers, few data point out the possible existence of local vertical connections across major tectonic structures. In order to select the most plausible options for the numerical modelling, IRSN compiled published studies and carried out fieldwork analysis to provide new data for its hydrogeological conceptual model. Relevant geological data can be considered both at the kilometre scale and at the metre scale. At the kilometre scale, the litho-stratigraphic scheme both for Dogger and Oxfordian series had previously been documented in the MHM area. Regional sedimentologic and diagenetic models are available for the Oxfordian aquifer and partially for the Dogger aquifer. Our fieldwork analysis complete these models thanks to new correlations pointed out during detailed iso-hyps mapping performed by G2R laboratory, southeast from the MHM area. Unlike the Kimmeridgian and COX sedimentary piles, which are

  8. Understanding Etna flank instability through numerical models

    Science.gov (United States)

    Apuani, Tiziana; Corazzato, Claudia; Merri, Andrea; Tibaldi, Alessandro

    2013-02-01

    mainly devoted to evaluate the effect of topography, geometry and rheological behaviour of the structural units. The 3D numerical model, extended 40 × 60 km, was implemented to simulate the volcano deformation pattern. First, the role of the Pleistocene subetnean clays was investigated, then, two "structural weakness zones" - the Pernicana Fault system and the NE rift - were introduced and their effects on the flank instability evaluated. Two extreme hydrogeological conditions, drained and undrained, were analysed. The results are expressed in terms of stress-strain field, displacement pattern, plasticity states and shear strain increments. Two main instability mechanisms were identified: one at shallow depth, with the sliding surface located inside the subetnean Quaternary clay, and another deep-seated mechanism with a not continuous and less evident sliding surface, developed inside the Apennine-Maghrebian Chain flysch, bordered by active structures. Both mechanisms contribute to explain the present deformation pattern and some of the main structures of the Etna flank. The effect of magma pressure exerted on the active dyke walls during eruptions was then simulated and relations between magmatic activity and flank instability were preliminarily investigated.

  9. A conceptual hydrogeologic model for the hydrogeologic framework, geochemistry, and groundwater-flow system of the Edwards-Trinity and related aquifers in the Pecos County region, Texas

    Science.gov (United States)

    Thomas, Jonathan V.; Stanton, Gregory P.; Bumgarner, Johnathan R.; Pearson, Daniel K.; Teeple, Andrew; Houston, Natalie A.; Payne, Jason; Musgrove, MaryLynn

    2013-01-01

    The Edwards-Trinity aquifer is a vital groundwater resource for agricultural, industrial, and municipal uses in the Trans-Pecos region of west Texas. A conceptual model of the hydrogeologic framework, geochemistry, and groundwater-flow system in the 4,700 square-mile study area was developed by the U.S. Geological Survey (USGS) in cooperation with the Middle Pecos Groundwater Conservation District, Pecos County, City of Fort Stockton, Brewster County, and Pecos County Water Control and Improvement District No. 1. The model was developed to gain a better understanding of the groundwater system and to establish a scientific foundation for resource-management decisions. Data and information were collected or obtained from various sources to develop the model. Lithologic information obtained from well reports and geophysical data were used to describe the hydrostratigraphy and structural features of the groundwater system, and aquifer-test data were used to estimate aquifer hydraulic properties. Groundwater-quality data were used to evaluate groundwater-flow paths, water and rock interaction, aquifer interaction, and the mixing of water from different sources. Groundwater-level data also were used to evaluate aquifer interaction as well as to develop a potentiometric-surface map, delineate regional groundwater divides, and describe regional groundwater-flow paths.

  10. Numerical Modeling of Ocean Circulation

    Science.gov (United States)

    Miller, Robert N.

    2007-01-01

    The modelling of ocean circulation is important not only for its own sake, but also in terms of the prediction of weather patterns and the effects of climate change. This book introduces the basic computational techniques necessary for all models of the ocean and atmosphere, and the conditions they must satisfy. It describes the workings of ocean models, the problems that must be solved in their construction, and how to evaluate computational results. Major emphasis is placed on examining ocean models critically, and determining what they do well and what they do poorly. Numerical analysis is introduced as needed, and exercises are included to illustrate major points. Developed from notes for a course taught in physical oceanography at the College of Oceanic and Atmospheric Sciences at Oregon State University, this book is ideal for graduate students of oceanography, geophysics, climatology and atmospheric science, and researchers in oceanography and atmospheric science. Features examples and critical examination of ocean modelling and results Demonstrates the strengths and weaknesses of different approaches Includes exercises to illustrate major points and supplement mathematical and physical details

  11. Numerical modelling of fuel sprays

    Energy Technology Data Exchange (ETDEWEB)

    Bergstroem, C.

    1999-06-01

    The way the fuel is introduced into the combustion chamber is one of the most important parameters for the power output and the generation of emissions in the combustion of liquid fuels. The interaction between the turbulent gas flow field and the liquid fuel droplets, the vaporisation of them and the mixing of the gaseous fuel with the ambient air that are vital parameters in the combustion process. The use of numerical calculations is an important tool to better understand these complex interacting phenomena. This thesis reports on the numerical modelling of fuel sprays in non-reacting cases using an own developed spray module. The spray module uses the stochastic parcel method to represent the spray. The module was made in such manner that it could by coupled with different gas flow solver. Results obtained from four different gas flow solvers are presented in the thesis, including the use of two different kinds of turbulence models. In the first part the spray module is coupled with a k-{eta} based 2-D cylindrical gas flow solver. A thorough sensitivity analysis was performed on the spray and gas flow solver parameters, such as grid size dependence and sensitivity to initial values of k-{eta}. The results of the spray module were also compared to results from other spray codes, e.g. the well known KIVA code. In the second part of this thesis the spray was injected into a turbulent and fully developed crossflow studied. The spray module was attached to a LES (Large Eddy Simulation) based flow solvers enabling the study of the complex structures and time dependent phenomena involved in spray in crossflows. It was found that the spray performs an oscillatory motion and that the Strouhal number in the wake was about 0.1. Different spray breakup models were evaluated by comparing with experimental results 66 refs, 56 figs

  12. Large-Scale Transport Model Uncertainty and Sensitivity Analysis: Distributed Sources in Complex Hydrogeologic Systems

    International Nuclear Information System (INIS)

    Sig Drellack, Lance Prothro

    2007-01-01

    The Underground Test Area (UGTA) Project of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office is in the process of assessing and developing regulatory decision options based on modeling predictions of contaminant transport from underground testing of nuclear weapons at the Nevada Test Site (NTS). The UGTA Project is attempting to develop an effective modeling strategy that addresses and quantifies multiple components of uncertainty including natural variability, parameter uncertainty, conceptual/model uncertainty, and decision uncertainty in translating model results into regulatory requirements. The modeling task presents multiple unique challenges to the hydrological sciences as a result of the complex fractured and faulted hydrostratigraphy, the distributed locations of sources, the suite of reactive and non-reactive radionuclides, and uncertainty in conceptual models. Characterization of the hydrogeologic system is difficult and expensive because of deep groundwater in the arid desert setting and the large spatial setting of the NTS. Therefore, conceptual model uncertainty is partially addressed through the development of multiple alternative conceptual models of the hydrostratigraphic framework and multiple alternative models of recharge and discharge. Uncertainty in boundary conditions is assessed through development of alternative groundwater fluxes through multiple simulations using the regional groundwater flow model. Calibration of alternative models to heads and measured or inferred fluxes has not proven to provide clear measures of model quality. Therefore, model screening by comparison to independently-derived natural geochemical mixing targets through cluster analysis has also been invoked to evaluate differences between alternative conceptual models. Advancing multiple alternative flow models, sensitivity of transport predictions to parameter uncertainty is assessed through Monte Carlo simulations. The

  13. Waste Disposal: Long-term Performance Studies for Radioactive Waste Disposal and Hydrogeological Modelling

    Energy Technology Data Exchange (ETDEWEB)

    Marivoet, J

    2000-07-01

    The main objectives of SCK-CEN's R and D programme on long-term performance studies are: (1) to develop a methodology and associated tools for assessing the long-term safety of geological disposal of all types of radioactive waste in clay formations and of the shallow-land burial of low-level waste; (2) to assess the performance and to identify the most influential elements of integrated repository systems for the disposal of radioactive waste; (3) to collect geological, piezometric and hydraulic data required for studying the hydrogeological system in north-eastern Belgium; (4) to develop a regional aquifer model for north-easter Belgium and to apply it in the performance assessments for the Mol site; (5) to test, verify and improve computer codes used in the performance assessment calculations of waste disposal concepts and contaminated sites (the computer codes simulate water flow and transport of radionuclides in engineered barriers, aquifers and contaminated sites). The scientific programme and achievements in 1999 are described.

  14. Karst connections between unconfined aquifers and the Upper Floridan aquifer in south Georgia: geophysical evidence and hydrogeological models

    Science.gov (United States)

    Thieme, D. M.; Denizman, C.

    2011-12-01

    Buried karst features in sedimentary rocks of the south Georgia Coastal Plain present a challenge for hydrogeological models of recharge and confined flow within the underlying Upper Floridan aquifer. The Withlacoochee River, the trunk stream for the area, frequently disappears into subsurface caverns as it makes its way south to join the Suwannee River in northern Florida. The Withlacoochee also receives inputs from small ponds and bays which in turn receive spring and seep groundwater inputs. We have mapped karst topography at the "top of rock" using ground-penetrating radar (GPR). Up to seven meters of relief is indicated for the paleotopography on Miocene to Pliocene rocks, contrasting with the more subdued relief of the modern landscape. Current stratigraphic and hydrogeological reconstructions do not incorporate this amount of relief or lateral variation in the confining beds. One "pipe" which is approximately four meters in diameter is being mapped in detail. We have field evidence at this location for rapid movement of surficial pond and river water with a meteoric signature through several separate strata of sedimentary rock into an aquifer in the Hawthorn formation. We use our geophysical and hydrological field evidence to constrain quantitative hydrogeological models for the flow rates into and out of both this upper aquifer and the underlying Upper Floridan aquifer, which is generally considered to be confined by the clays of the Hawthorn.

  15. SR-Site Pre-modelling: Sensitivity studies of hydrogeological model variants for the Laxemar site using CONNECTFLOW

    Energy Technology Data Exchange (ETDEWEB)

    Joyce, Steven; Hoek, Jaap; Hartley, Lee (Serco (United Kingdom)); Marsic, Niko (Kemakta Konsult AB, Stockholm (Sweden))

    2010-12-15

    This study investigated a number of potential model variants of the SR-Can hydrogeological models of the temperate period and the sensitivity of the performance measures to the chosen parameters. This will help to guide the choice of potential variants for the SR-Site project and provide an input to design premises for the underground construction of the repository. It was found that variation of tunnel backfill properties in the tunnels had a significant effect on performance measures, but in the central area, ramps and shafts it had a lesser effect for those property values chosen. Variation of tunnel EDZ properties only had minor effects on performance measures. The presence of a crown space in the deposition tunnels had a significant effect on the tunnel performance measures and a lesser effect on the rock and EDZ performance measures. The presence of a deposition hole EDZ and spalling also had an effect on the performance measures.

  16. Final Technical Report - Integrated Hydrogeophysical and Hydrogeologic Driven Parameter Upscaling for Dual-Domain Transport Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Shafer, John M

    2012-11-05

    The three major components of this research were: 1. Application of minimally invasive, cost effective hydrogeophysical techniques (surface and borehole), to generate fine scale (~1m or less) 3D estimates of subsurface heterogeneity. Heterogeneity is defined as spatial variability in hydraulic conductivity and/or hydrolithologic zones. 2. Integration of the fine scale characterization of hydrogeologic parameters with the hydrogeologic facies to upscale the finer scale assessment of heterogeneity to field scale. 3. Determination of the relationship between dual-domain parameters and practical characterization data.

  17. Applications of hydrogeological modelling methodology using NAMMU and CONNECTFLOW. Task 1, 2, 3 and 4

    International Nuclear Information System (INIS)

    Gylling, Bjoern; Marsic, Niko; Hartley, Lee; Holton, David

    2004-11-01

    It is planned to store spent nuclear fuel at depth in crystalline rock in Sweden. Site investigations are carried out to confirm if the suggested sites are appropriate. Modelling of groundwater flow and transport may be used to aid the site investigation and is also an important part of the safety assessment of a site. A good design of the repository will enhance the safety. To support the site investigation phase and the design of underground repositories four tasks have been performed. These tasks are all related to the CONNECTFLOW groundwater flow modelling concept. CONNECTFLOW is a suite of software that includes: the continuum porous medium (CPM) concept as implemented in NAMMU, the discrete fracture network (DFN) concept as implemented in NAPSAC, the ability to nest these two representations into a single combined model. As an integrated suite of hydrogeological modelling tools CONNECTFLOW offers several benefits: the ability to nest different scales of the model from the canister-scale to the regional scale to resolve detailed flow behaviour around the waste packages in the context of the overall hydrogeological situation at a site, nesting is flexible as embedded fine-scale CPM regions can be nested within coarser CPM models, multiple DFN regions can be nested inside CPM models, and CPM models can be nested within DFN models, nesting of regions is precise in that the system is solved in a single step with equations at the interface between nested regions that ensure both continuity of pressure and conservation of mass flux between the regions. This ensures a flux-balance between the two-scales, and hence offers greater consistency than two-step nesting or only implementing pressure continuity, the ability to upscale DFN models to obtain the equivalent CPM properties on a variety of scales ensures that the modeler can move between DFN and SC concepts easily in a self-consistent way. The aim of the current tasks is to demonstrate and test the CONNECTFLOW

  18. Modelling of hydro-zones for layout planning and numerical flow model in 2006

    International Nuclear Information System (INIS)

    Ahokas, H.; Vaittinen, T.; Tammisto, E.; Nummela, J.

    2007-11-01

    As part of the programme for the final disposal of spent nuclear fuel, a model was compiled of hydrogeologically significant zones on the Olkiluoto site. These deterministic zones dominate the groundwater flow especially deep in the bedrock, and because of their nature intersections by disposal tunnels will be avoided, if possible. For layout planning purposes, a brief description was made of the deformation zones of the geological model that intersect the planned repository area and are of hydraulic significance from the point of view of long-term safety. In addition, the hydraulic properties of the zones and the bedrock outside the zones needed for the numerical flow simulations were described. Modelling was mainly based on hydrological observations including an extensive number of single-hole hydraulic tests as well as some long-term pumping test results. Some geophysical mise-a-la-masse results were also used in the compilation of the zones. A comparison between the modelled hydrogeological zones and the deformation zones identified in the geological model of the Olkiluoto site is also presented. (orig.)

  19. Hydrogeologic Framework Model for the Saturated-Zone Site-Scale Flow

    Energy Technology Data Exchange (ETDEWEB)

    Z. Peterman

    2003-03-05

    Yucca Mountain is being evaluated as a potential site for development of a geologic repository for the permanent disposal of spent nuclear fuel and high-level radioactive waste. Ground water is considered to be the principal means for transporting radionuclides that may be released from the potential repository to the accessible environment, thereby possibly affecting public health and safety. The ground-water hydrology of the region is a result of both the arid climatic conditions and the complex geology. Ground-water flow in the Yucca Mountain region generally can be described as consisting of two main components: a series of relatively shallow and localized flow paths that are superimposed on deeper regional flow paths. A significant component of the regional ground-water flow is through a thick, generally deep-lying, Paleozoic carbonate rock sequence. Locally within the potential repository area, the flow is through a vertical sequence of welded and nonwelded tuffs that overlie the carbonate aquifer. Downgradient from the site, these tuffs terminate in basin fill deposits that are dominated by alluvium. Throughout the system, extensive and prevalent faults and fractures may control ground-water flow. The purpose of this Analysis/Modeling Report (AMR) is to document the three-dimensional (3D) hydrogeologic framework model (HFM) that has been constructed specifically to support development of a site-scale ground-water flow and transport model. Because the HFM provides the fundamental geometric framework for constructing the site-scale 3D ground-water flow model that will be used to evaluate potential radionuclide transport through the saturated zone (SZ) from beneath the potential repository to down-gradient compliance points, the HFM is important for assessing potential repository system performance. This AMR documents the progress of the understanding of the site-scale SZ ground-water flow system framework at Yucca Mountain based on data through July 1999. The

  20. 3-D basin modelling of the Paris Basin: diagenetic and hydrogeologic implications

    International Nuclear Information System (INIS)

    Violette, S.; Goncalves, J.; Jost, A.; Marsily, G. de

    2004-01-01

    A 3-D basin model of the Paris basin is presented in order to simulate through geological times fluid, heat and solute fluxes. This study emphasizes: i) the contribution of basin models to the quantitative hydrodynamic understanding of behaviour of the basin over geological times; ii) the additional use of Atmospheric General Circulation model (AGCM) to provide palaeo-climatic boundaries for a coupled flow and mass transfer modelling, constrained by geochemical and isotopic tracers and; iii) the integration of different types of data (qualitative and quantitative) to better constrain the simulations. Firstly, in a genetic way, basin model is used to reproduce geological, physical and chemical processes occurring in the course of the 248 My evolution of the Paris basin that ought to explain the present-day hydraulic properties at the regional scale. As basin codes try to reproduce some of these phenomena, they should be able to give a plausible idea of the regional-scale permeability distribution of the multi-layered system, of the pre-industrial hydrodynamic conditions within the aquifers and of the diagenesis timing and type of hydrodynamic processes involved. Secondly, climate records archived in the Paris basin groundwater suggest that climate and morphological features have an impact on the hydrogeological processes, particularly during the last 5 My. An Atmospheric General Circulation model is used with a refined spatial resolution centred on the Paris basin to reproduce the climate for the present, the Last Glacial Maximum (21 ky) and the middle Pliocene (3 My). These climates will be prescribed, through forcing functions to the hydrological code with the main objective of understanding the way aquifers and aquitards react under different climate conditions, the period and the duration of these effects. Finally, the Paris basin has been studied for a number of years by different scientific communities, thus a large amount of data has been collected. By

  1. Hydrogeology of the West Siberian Basin

    International Nuclear Information System (INIS)

    Foley, M.G.; Bradley, D.J.; Cole, C.R.

    1996-01-01

    Nuclear fuel cycle activities of the former Soviet Union (FSU) have resulted in extensive radioactive contaminant releases to the environment in western Siberia. We are developing three-dimensional numerical models of the hydrogeology and potential contaminant migration in the West Siberian Basin. We have assumed that ground-water flow in the West Siberian Basin is topographically driven, with recharge to the basin occurring in the highlands on the west, east, and south, and internal discharge localized in numerous river valleys and lakes that ultimately discharge north to the ocean. We are modeling the regional hydrogeology as three-dimensional, steady-state, saturated flow that is recharged from above. We acquired topographic, geologic, hydrostratigraphic, hydrogeologic, and water-balance data for the West Siberian Basin and constructed a regional water table. We correlated and combined 70 different rock types derived from published descriptions of West Siberian Basin rocks into 17 rock types appropriate for assignment of hydrogeologic properties on the basis of spatial heterogeneity and constituent (i.e., sand, silt, and clay) diversity. Examination of resulting three-dimensional assemblages of rock types showed that they were consistent with published and inferred paleogeography and depositional processes. Calibrating the basin's moisture balance (i.e., recharge and discharge) to the derived water table determined plausible input parameter values for unknowns such as hydraulic conductivities. The general directions of calculated ground-water flow suggest that major rivers act as discharge areas, with upwelling below the rivers extending down into the basement rocks, and that ground-water divides that penetrate the entire thickness of the model are evident between major rivers

  2. Multiple-point statistical simulation for hydrogeological models: 3-D training image development and conditioning strategies

    Science.gov (United States)

    Høyer, Anne-Sophie; Vignoli, Giulio; Mejer Hansen, Thomas; Thanh Vu, Le; Keefer, Donald A.; Jørgensen, Flemming

    2017-12-01

    Most studies on the application of geostatistical simulations based on multiple-point statistics (MPS) to hydrogeological modelling focus on relatively fine-scale models and concentrate on the estimation of facies-level structural uncertainty. Much less attention is paid to the use of input data and optimal construction of training images. For instance, even though the training image should capture a set of spatial geological characteristics to guide the simulations, the majority of the research still relies on 2-D or quasi-3-D training images. In the present study, we demonstrate a novel strategy for 3-D MPS modelling characterized by (i) realistic 3-D training images and (ii) an effective workflow for incorporating a diverse group of geological and geophysical data sets. The study covers an area of 2810 km2 in the southern part of Denmark. MPS simulations are performed on a subset of the geological succession (the lower to middle Miocene sediments) which is characterized by relatively uniform structures and dominated by sand and clay. The simulated domain is large and each of the geostatistical realizations contains approximately 45 million voxels with size 100 m × 100 m × 5 m. Data used for the modelling include water well logs, high-resolution seismic data, and a previously published 3-D geological model. We apply a series of different strategies for the simulations based on data quality, and develop a novel method to effectively create observed spatial trends. The training image is constructed as a relatively small 3-D voxel model covering an area of 90 km2. We use an iterative training image development strategy and find that even slight modifications in the training image create significant changes in simulations. Thus, this study shows how to include both the geological environment and the type and quality of input information in order to achieve optimal results from MPS modelling. We present a practical workflow to build the training image and

  3. Use of a risk-based hydrogeologic model to set remedial goals in a Puget Sound basin watershed

    International Nuclear Information System (INIS)

    Pascoe, G.; Gould, L.; Martin, J.; Riley, M.; Floyd, T.

    1995-01-01

    The Port of Seattle is redeveloping industrial land for a container terminal along the southwest Seattle waterfront. Concrete, asphalt, ballast, and a landfill geomembrane will cover the site and prevent direct contact with surface soils, so remedial goals focused on groundwater contamination from subsurface soils. Groundwater at the site flows along an old stormwater drain, in a filled estuary of a small creek, to Elliott Bay. Remedial goals for a variety of organic chemicals, metals, and TPH in subsurface soils were identified to protect marine receptors in the bay and their consumers. Washington State and federal marine water quality criteria were the starting points in the risk-based model, and corresponding concentrations of chemicals in groundwater were back-calculated through a hydrogeologic model. The hydrogeologic model included a mixing zone component in the bay and dilution/attenuation factors along the groundwater transport pathway that were determined from onsite groundwater and surface water chemical concentrations. A rearranged Summers equation was then applied in a second back-calculation to determine subsurface soil concentrations corresponding to the back calculated groundwater concentrations. The equation was based on calculated aquifer flow rates for the small creek watershed and rates of infiltration through surface materials calculated for each redevelopment soil cover type by the HELP model. Results of the risk-based hydrogeologic back-calculation model indicate that, depending on soil cover type at the site, concentrations in subsurface soils of PCBs from 2 to 1,000 mg/kg and of TPH up to free phase concentration would not result in risks to marine organisms or their consumers in Elliott Bay

  4. Numerical modeling of slow shocks

    International Nuclear Information System (INIS)

    Winske, D.

    1987-01-01

    This paper reviews previous attempt and the present status of efforts to understand the structure of slow shocks by means of time dependent numerical calculations. Studies carried out using MHD or hybrid-kinetic codes have demonstrated qualitative agreement with theory. A number of unresolved issues related to hybrid simulations of the internal shock structure are discussed in some detail. 43 refs., 8 figs

  5. Status report: numerical modeling of ground-water flow in the Paleozoic formations, western Paradox Basin, Utah

    International Nuclear Information System (INIS)

    Dunbar, D.B.; Thackston, J.W.

    1985-10-01

    A three-dimensional finite-difference numerical model was applied to simulate the ground-water flow pattern in Paleozoic strata within the western Paradox Basin region. The primary purpose of the modeling was to test the present conceptual hydrogeologic model and evaluate data deficiencies. All available data on ground-water hydrology, although sparse in this area, were utilized as input to the model. Permeability and potentiometric levels were estimated from petroleum company drill-stem tests and water-supply wells; formation thicknesses were obtained from geologic correlation of borehole geophysical logs. Hydrogeologic judgment weighed heavily in the assignment of hydrologic values to geologic features for this preliminary modeling study. Calibration of the model was accomplished through trial-and-error matching of simulated potentiometric contours with available head data. Hypothetical flow patterns, flux rates, recharge amounts, and surface discharge amounts were produced by the model. 34 refs., 17 figs., 3 tabs

  6. On uncertainty quantification in hydrogeology and hydrogeophysics

    Science.gov (United States)

    Linde, Niklas; Ginsbourger, David; Irving, James; Nobile, Fabio; Doucet, Arnaud

    2017-12-01

    Recent advances in sensor technologies, field methodologies, numerical modeling, and inversion approaches have contributed to unprecedented imaging of hydrogeological properties and detailed predictions at multiple temporal and spatial scales. Nevertheless, imaging results and predictions will always remain imprecise, which calls for appropriate uncertainty quantification (UQ). In this paper, we outline selected methodological developments together with pioneering UQ applications in hydrogeology and hydrogeophysics. The applied mathematics and statistics literature is not easy to penetrate and this review aims at helping hydrogeologists and hydrogeophysicists to identify suitable approaches for UQ that can be applied and further developed to their specific needs. To bypass the tremendous computational costs associated with forward UQ based on full-physics simulations, we discuss proxy-modeling strategies and multi-resolution (Multi-level Monte Carlo) methods. We consider Bayesian inversion for non-linear and non-Gaussian state-space problems and discuss how Sequential Monte Carlo may become a practical alternative. We also describe strategies to account for forward modeling errors in Bayesian inversion. Finally, we consider hydrogeophysical inversion, where petrophysical uncertainty is often ignored leading to overconfident parameter estimation. The high parameter and data dimensions encountered in hydrogeological and geophysical problems make UQ a complicated and important challenge that has only been partially addressed to date.

  7. Tono regional hydrogeological study project. Annual report 2004

    International Nuclear Information System (INIS)

    Iwatsuki, Teruki; Ota, Kunio; Takeuchi, Shinji; Amano, Kenji; Takeuchi, Ryuji; Saegusa, Hiromitsu; Osawa, Hideaki

    2005-09-01

    Tono Geoscience Center, Japan Nuclear Cycle Development Institute has been conducting a wide range of geoscientific research in order to build firm scientific and technological basis for the research and development of geological disposal. One of the geoscientific research programme is a Regional Hydrogeological Study (RHS) project in the Tono region, central Japan. This report mainly summarizes the results of research in DH-14 and DH-15 boreholes at Toki city and Mizunami city in fiscal year 2004 which were carried out to support and improve the results in fiscal year 2003. The research in the regional scale area shows the reliability of conceptual hydrogeological model and numerical simulation for the evaluation of regional hydrogeology. On the other hand, the geological and geophysical investigation, and borehole investigation during the surface-based investigations in the local scale area provide the pragmatic distribution of hydrogeological structure that may control regional groundwater hydrology. Hydrogeological simulations regarding the geological structure such as fault and hydrogeological property demonstrate the priority of investigation of geological structure for the evaluation of hydrogeology. The fault perpendicular to groundwater flow direction crucially affects on regional hydrology. Such fault is necessary to be investigated by priority. Hydrochemical investigation shows that chemical evolution process in this groundwater illustrated is mixing between groundwaters with different salinities. Principal component analysis and mass balance calculation reveal reliable chemistry of end-member waters for mixing. Regarding methodology development, the strategy and procedure of investigations are summarized based on the results of surface-based investigation. Moreover the multi interval monitoring system for water pressure and temperature has developed and started to monitor the in-situ condition of groundwater. The geology, geological structure, hydraulic

  8. Numerical Modelling of Electrical Discharges

    International Nuclear Information System (INIS)

    Durán-Olivencia, F J; Pontiga, F; Castellanos, A

    2014-01-01

    The problem of the propagation of an electrical discharge between a spherical electrode and a plane has been solved by means of finite element methods (FEM) using a fluid approximation and assuming weak ionization and local equilibrium with the electric field. The numerical simulation of this type of problems presents the usual difficulties of convection-diffusion-reaction problems, in addition to those associated with the nonlinearities of the charged species velocities, the formation of steep gradients of the electric field and particle densities, and the coexistence of very different temporal scales. The effect of using different temporal discretizations for the numerical integration of the corresponding system of partial differential equations will be here investigated. In particular, the so-called θ-methods will be used, which allows to implement implicit, semi-explicit and fully explicit schemes in a simple way

  9. Numerical modelling in material physics

    International Nuclear Information System (INIS)

    Proville, L.

    2004-12-01

    The author first briefly presents his past research activities: investigation of a dislocation sliding in solid solution by molecular dynamics, modelling of metal film growth by phase field and Monte Carlo kinetics, phase field model for surface self-organisation, phase field model for the Al 3 Zr alloy, calculation of anharmonic photons, mobility of bipolarons in superconductors. Then, he more precisely reports the mesoscopic modelling in phase field, and some atomistic modelling (dislocation sliding, Monte Carlo simulation of metal surface growth, anharmonic network optical spectrum modelling)

  10. Hydrogeology of Rome

    Directory of Open Access Journals (Sweden)

    Roberto Mazza

    2015-12-01

    Full Text Available In this paper the hydrogeological setting of Rome is figured out. This setting has been strongly influenced by different factors as tectonic activity, volcanism and seal level variations. The conceptual model of the groundwater flow in the roman area is represented by four aquifers, three of which being overlappingones. These aquifers flow from peripheral sectors of the study area toward Tiber and Aniene Rivers and the Sea.

  11. Numerical modelling approach for mine backfill

    Indian Academy of Sciences (India)

    Muhammad Zaka Emad

    2017-07-24

    Jul 24, 2017 ... conditions. This paper discusses a numerical modelling strategy for modelling mine backfill material. The .... placed in an ore pass that leads the ore to the ore bin and crusher, from ... 1 year, depending on the mine plan.

  12. Numerical modeling of thermal conductive heating in fractured bedrock.

    Science.gov (United States)

    Baston, Daniel P; Falta, Ronald W; Kueper, Bernard H

    2010-01-01

    Numerical modeling was employed to study the performance of thermal conductive heating (TCH) in fractured shale under a variety of hydrogeological conditions. Model results show that groundwater flow in fractures does not significantly affect the minimum treatment zone temperature, except near the beginning of heating or when groundwater influx is high. However, fracture and rock matrix properties can significantly influence the time necessary to remove all liquid water (i.e., reach superheated steam conditions) in the treatment area. Low matrix permeability, high matrix porosity, and wide fracture spacing can contribute to boiling point elevation in the rock matrix. Consequently, knowledge of these properties is important for the estimation of treatment times. Because of the variability in boiling point throughout a fractured rock treatment zone and the absence of a well-defined constant temperature boiling plateau in the rock matrix, it may be difficult to monitor the progress of thermal treatment using temperature measurements alone. Copyright © 2010 The Author(s). Journal compilation © 2010 National Ground Water Association.

  13. Using sparse polynomial chaos expansions for the global sensitivity analysis of groundwater lifetime expectancy in a multi-layered hydrogeological model

    International Nuclear Information System (INIS)

    Deman, G.; Konakli, K.; Sudret, B.; Kerrou, J.; Perrochet, P.; Benabderrahmane, H.

    2016-01-01

    The study makes use of polynomial chaos expansions to compute Sobol' indices within the frame of a global sensitivity analysis of hydro-dispersive parameters in a simplified vertical cross-section of a segment of the subsurface of the Paris Basin. Applying conservative ranges, the uncertainty in 78 input variables is propagated upon the mean lifetime expectancy of water molecules departing from a specific location within a highly confining layer situated in the middle of the model domain. Lifetime expectancy is a hydrogeological performance measure pertinent to safety analysis with respect to subsurface contaminants, such as radionuclides. The sensitivity analysis indicates that the variability in the mean lifetime expectancy can be sufficiently explained by the uncertainty in the petrofacies, i.e. the sets of porosity and hydraulic conductivity, of only a few layers of the model. The obtained results provide guidance regarding the uncertainty modeling in future investigations employing detailed numerical models of the subsurface of the Paris Basin. Moreover, the study demonstrates the high efficiency of sparse polynomial chaos expansions in computing Sobol' indices for high-dimensional models. - Highlights: • Global sensitivity analysis of a 2D 15-layer groundwater flow model is conducted. • A high-dimensional random input comprising 78 parameters is considered. • The variability in the mean lifetime expectancy for the central layer is examined. • Sparse polynomial chaos expansions are used to compute Sobol' sensitivity indices. • The petrofacies of a few layers can sufficiently explain the response variance.

  14. The physical hydrogeology of ore deposits

    Science.gov (United States)

    Ingebritsen, Steven E.; Appold, M.S.

    2012-01-01

    Hydrothermal ore deposits represent a convergence of fluid flow, thermal energy, and solute flux that is hydrogeologically unusual. From the hydrogeologic perspective, hydrothermal ore deposition represents a complex coupled-flow problem—sufficiently complex that physically rigorous description of the coupled thermal (T), hydraulic (H), mechanical (M), and chemical (C) processes (THMC modeling) continues to challenge our computational ability. Though research into these coupled behaviors has found only a limited subset to be quantitatively tractable, it has yielded valuable insights into the workings of hydrothermal systems in a wide range of geologic environments including sedimentary, metamorphic, and magmatic. Examples of these insights include the quantification of likely driving mechanisms, rates and paths of fluid flow, ore-mineral precipitation mechanisms, longevity of hydrothermal systems, mechanisms by which hydrothermal fluids acquire their temperature and composition, and the controlling influence of permeability and other rock properties on hydrothermal fluid behavior. In this communication we review some of the fundamental theory needed to characterize the physical hydrogeology of hydrothermal systems and discuss how this theory has been applied in studies of Mississippi Valley-type, tabular uranium, porphyry, epithermal, and mid-ocean ridge ore-forming systems. A key limitation in the computational state-of-the-art is the inability to describe fluid flow and transport fully in the many ore systems that show evidence of repeated shear or tensional failure with associated dynamic variations in permeability. However, we discuss global-scale compilations that suggest some numerical constraints on both mean and dynamically enhanced crustal permeability. Principles of physical hydrogeology can be powerful tools for investigating hydrothermal ore formation and are becoming increasingly accessible with ongoing advances in modeling software.

  15. West Siberian basin hydrogeology - regional framework for contaminant migration from injected wastes

    International Nuclear Information System (INIS)

    Foley, M.G.

    1994-05-01

    Nuclear fuel cycle activities of the former Soviet Union (FSU) have resulted in massive contamination of the environment in western Siberia. We are developing three-dimensional numerical models of the hydrogeology and potential contaminant migration in the West Siberian Basin. Our long-term goal at Pacific Northwest Laboratory is to help determine future environmental and human impacts given the releases that have occurred to date and the current waste management practices. In FY 1993, our objectives were to (1) refine and implement the hydrogeologic conceptual models of the regional hydrogeology of western Siberia developed in FY 1992 and develop the detailed, spatially registered digital geologic and hydrologic databases to test them, (2) calibrate the computer implementation of the conceptual models developed in FY 1992, and (3) develop general geologic and hydrologic information and preliminary hydrogeologic conceptual models relevant to the more detailed models of contaminated site hydrogeology. Calibration studies of the regional hydrogeologic computer model suggest that most precipitation entering the ground-water system moves in the near-surface part of the system and discharges to surface waters relatively near its point of infiltration. This means that wastes discharged to the surface and near-surface may not be isolated as well as previously thought, since the wastes may be carried to the surface by gradually rising ground waters

  16. Numerical models of planetary dynamos

    International Nuclear Information System (INIS)

    Glatzmaier, G.A.; Roberts, P.H.

    1992-01-01

    We describe a nonlinear, axisymmetric, spherical-shell model of planetary dynamos. This intermediate-type dynamo model requires a prescribed helicity field (the alpha effect) and a prescribed buoyancy force or thermal wind (the omega effect) and solves for the axisymmetric time-dependent magnetic and velocity fields. Three very different time dependent solutions are obtained from different prescribed sets of alpha and omega fields

  17. GIS-based model of groundwater occurrence using geological and hydrogeological data in Precambrian Oban Massif southeastern Nigeria

    Science.gov (United States)

    Sikakwe, Gregory Udie

    2018-06-01

    This research modeled geological and hydrogeological controls on groundwater occurrence in Oban Massif and environs southeastern Nigeria. Topographical, hydrogeological, and structural maps, including lithology samples from drilled bores, well completion, and pumping test data in the study area were procured. Collection of coordinates of rock sample locations and structural data on strike and dip of rock exposures was collected. Geological and structural information collected was overlaid on the topographical, hydrogeological and structural map and digitized to produce the geological map of the study area. Thematic map on geological groundwater prospect map of the study was prepared using multicriteria evaluation. Relative weights were assigned to various rock types based on their relative contribution to groundwater occurrence and the map was reclassified using geographic information system (ArcGIS10.1) analysis. Depth ranges of the various lithologic units from drilled boreholes were used to construct lithologic correlation section of the boreholes across the study area using RockWorks16 Program software. Hydrogeological parameters such as storativity, specific capacity, transmissivity, drawdown, pumping rate, static water level, total depth, and well yield were computed from well completion reports and aquifer test. Results shows that the geologic groundwater prospect map was categorized into very good (28.73 m2), good (9.66 m2), moderate (35.08 m2), fair (49.38 m2), and poor (77.63 m2) zones. Aquifer parameters showed ranges such as (specific capacity (1.81-31.16 m2/day/m), transmissivity (0.0033-12 m2/day), storativity (9.4 × 10-3-2.3), drawdown (2.2-17.65 m), pumping rate (0.75-3.57 l/s), static water level (0-20.5 m), and total depth (3.3-61 m). Borehole depths obtained in the basement are shallower than those in the sedimentary area. Aquifer test parameters obtained from boreholes across the study indicate better correspondence with zones identified as

  18. Numerical Modeling of Microelectrochemical Systems

    DEFF Research Database (Denmark)

    Adesokan, Bolaji James

    incorporates the finite size of ionic species in the transport equation. The model presents a more appropriate boundary conditions which describe the modified Butler-Volmer reaction kinetics and account for the surface capacitance of the thin electric double layer. We also have found analytical solution...... at the electrode in a microelectrochemical system. In our analysis, we account for the finite size properties of ions in the mass and the charge transport of ionic species in an electrochemical system. This term characterizes the saturation of the ionic species close to the electrode surface. We then analyse......The PhD dissertation is concerned with mathematical modeling and simulation of electrochemical systems. The first three chapters of the thesis consist of the introductory part, the model development chapter and the chapter on the summary of the main results. The remaining three chapters report...

  19. Mathematical and Numerical Modeling in Maritime Geomechanics

    Directory of Open Access Journals (Sweden)

    Miguel Martín Stickle

    2012-04-01

    Full Text Available A theoretical and numerical framework to model the foundation of marine offshore structures is presented. The theoretical model is composed by a system of partial differential equations describing coupling between seabed solid skeleton and pore fluids (water, air, oil,... combined with a system of ordinary differential equations describing the specific constitutive relation of the seabed soil skeleton. Once the theoretical model is described, the finite element numerical procedure to achieve an approximate solution of the overning equations is outlined. In order to validate the proposed theoretical and numerical framework the seaward tilt mechanism induced by the action of breaking waves over a vertical breakwater is numerically reproduced. The results numerically attained are in agreement with the main conclusions drawn from the literature associated with this failure mechanism.

  20. Numerical modelling of reflood processes

    International Nuclear Information System (INIS)

    Glynn, D.R.; Rhodes, N.; Tatchell, D.G.

    1983-01-01

    The use of a detailed computer model to investigate the effects of grid size and the choice of wall-to-fluid heat-transfer correlations on the predictions obtained for reflooding of a vertical heated channel is described. The model employs equations for the momentum and enthalpy of vapour and liquid and hence accounts for both thermal non-equilibrium and slip between the phases. Empirical correlations are used to calculate interphase and wall-to-fluid friction and heat-transfer as functions of flow regime and local conditions. The empirical formulae have remained fixed with the exception of the wall-to-fluid heat-transfer correlations. These have been varied according to the practices adopted in other computer codes used to model reflood, namely REFLUX, RELAP and TRAC. Calculations have been performed to predict the CSNI standard problem number 7, and the results are compared with experiment. It is shown that the results are substantially grid-independent, and that the choice of correlation has a significant influence on the general flow behaviour, the rate of quenching and on the maximum cladding temperature predicted by the model. It is concluded that good predictions of reflooding rates can be obtained with particular correlation sets. (author)

  1. Nirex 97 an assessment of the post-closure performance of a deep waste repository at Sellafield. Volume 2; hydrogeological conceptual model development - effective parameters and calibration appendix

    International Nuclear Information System (INIS)

    Jackson, C.; Watson, S.

    1997-01-01

    repository zone beneath Longlands Farm. In style, scope and presentation, Nirex 97 is primarily aimed at the scientific community, other radioactive waste disposal agencies and regulators. The report is published as part of Nirex's commitment to open publication of its scientific findings. The main value of the report currently is as a demonstration of the generic capability which has been developed to assess the radiological safety performance of candidate repository sites. The safety assessment reported as Nirex 97 was carried out between April 1996 and August 1997. It updates a preliminary assessment of the groundwater pathway for a repository at Sellafield, 'Nirex 95' published in July 1995. Nirex 97 takes account of further data obtained from the Nirex waste inventory, design, site characterisation and research programmes. In addition, Nirex 97 extends the Nirex 95 evaluation to include consideration of the potential radiological and flammability hazards in the biosphere arising from the effects of gas generation within the repository and the extent of pressurisation within the repository vaults. The assessment also takes account of the latest guidance from the Environment Agencies on requirements for authorisation of disposal facilities on land. Volume 2: Hydrogeological Model Development - Effective Parameters and Calibration, explains the steps followed to interpret and process field data in order to build a variety of two- and three-dimensional numerical models of groundwater flow. It describes the process of upscaling used to derive effective hydrogeological parameters for the hydrogeological units represented in these numerical models. The calibration of these numerical models is discussed

  2. Nirex 97 an assessment of the post-closure performance of a deep waste repository at Sellafield. Volume 2; hydrogeological conceptual model development - effective parameters and calibration

    International Nuclear Information System (INIS)

    Jackson, C.; Watson, S.

    1997-01-01

    repository zone beneath Longlands Farm. In style, scope and presentation, Nirex 97 is primarily aimed at the scientific community, other radioactive waste disposal agencies and regulators. The report is published as part of Nirex's commitment to open publication of its scientific findings. The main value of the report currently is as a demonstration of the generic capability which has been developed to assess the radiological safety performance of candidate repository sites. The safety assessment reported as Nirex 97 was carried out between April 1996 and August 1997. It updates a preliminary assessment of the groundwater pathway for a repository at Sellafield, 'Nirex 95' published in July 1995. Nirex 97 takes account of further data obtained from the Nirex waste inventory, design, site characterisation and research programmes. In addition, Nirex 97 extends the Nirex 95 evaluation to include consideration of the potential radiological and flammability hazards in the biosphere arising from the effects of gas generation within the repository and the extent of pressurisation within the repository vaults. The assessment also takes account of the latest guidance from the Environment Agencies on requirements for authorisation of disposal facilities on land. Volume 2: Hydrogeological Model Development - Effective Parameters and Calibration, explains the steps followed to interpret and process field data in order to build a variety of two- and three-dimensional numerical models of groundwater flow. It describes the process of upscaling used to derive effective hydrogeological parameters for the hydrogeological units represented in these numerical models. The calibration of these numerical models is discussed

  3. Hydrogeologic influence on changes in snowmelt runoff with climate warming: Numerical experiments on a mid-elevation catchment in the Sierra Nevada, USA

    Science.gov (United States)

    S.M. Jepsen; T.C. Harmon; M.W. Meadows; C.T. Hunsaker

    2016-01-01

    The role of hydrogeology in mediating long-term changes in mountain streamflow, resulting from reduced snowfall in a potentially warmer climate, is currently not well understood. We explore this by simulating changes in stream discharge and evapotranspiration from a mid-elevation, 1-km2 catchment in the southern Sierra Nevada of California (USA)...

  4. Model Intercomparison Study to Investigate a Dense Contaminant Plume in a Complex Hydrogeologic System

    International Nuclear Information System (INIS)

    Williams, Mark D.; Cole, Charles R.; Foley, Michael G.; Zinina, Galina A.; Zinin, Alexander I.; Vasil'Kova, Nelly A.; Samsonova, Lilia M.

    2001-01-01

    A joint Russian and U.S. model intercomparison study was undertaken for developing more realistic contaminant transport models of the Mayak Site, Southern Urals. The test problems were developed by the Russian Team based on their experience modeling contaminant migration near Lake Karachai. The intercomparison problems were designed to address lake and contaminant plume interactions, as well as river interactions and plume density effects. Different numerical codes were used. Overall there is good agreement between the results of both models. Features shown by both models include (1) the sinking of the plume below the lake, (2) the raising of the water table in the fresh water adjacent to the lake in response to the increased pressure from the dense plume, and (3) the formation of a second sinking plume in an area where evapotranspiration exceeded infiltration, thus increasing the solute concentrations above the source (i.e., lake) values

  5. Three-dimensional hydrogeological modeling to assess the elevated-water-table technique for controlling acid generation from an abandoned tailings site in Quebec, Canada

    Science.gov (United States)

    Ethier, Marie-Pier; Bussière, Bruno; Broda, Stefan; Aubertin, Michel

    2018-01-01

    The Manitou Mine sulphidic-tailings storage facility No. 2, near Val D'Or, Canada, was reclaimed in 2009 by elevating the water table and applying a monolayer cover made of tailings from nearby Goldex Mine. Previous studies showed that production of acid mine drainage can be controlled by lowering the oxygen flux through Manitou tailings with a water table maintained at the interface between the cover and reactive tailings. Simulations of different scenarios were performed using numerical hydrogeological modeling to evaluate the capacity of the reclamation works to maintain the phreatic surface at this interface. A large-scale numerical model was constructed and calibrated using 3 years of field measurements. This model reproduced the field measurements, including the existence of a western zone on the site where the phreatic level targeted is not always met during the summer. A sensitivity analysis was performed to assess the response of the model to varying saturated hydraulic conductivities, porosities, and grain-size distributions. Higher variations of the hydraulic heads, with respect to the calibrated scenario results, were observed when simulating a looser or coarser cover material. Long-term responses were simulated using: the normal climatic data, data for a normal climate with a 2-month dry spell, and a simplified climate-change case. Environmental quality targets were reached less frequently during summer for the dry spell simulation as well as for the simplified climate-change scenario. This study illustrates how numerical simulations can be used as a key tool to assess the eventual performance of various mine-site reclamation scenarios.

  6. Recent advances in numerical modeling of detonations

    Energy Technology Data Exchange (ETDEWEB)

    Mader, C.L.

    1986-12-01

    Three lectures were presented on recent advances in numerical modeling detonations entitled (1) Jet Initiation and Penetration of Explosives; (2) Explosive Desensitization by Preshocking; (3) Inert Metal-Loaded Explosives.

  7. A numerical reference model for themomechanical subduction

    DEFF Research Database (Denmark)

    Quinquis, Matthieu; Chemia, Zurab; Tosi, Nicola

    2010-01-01

    Building an advanced numerical model of subduction requires choosing values for various geometrical parameters and material properties, among others, the initial lithosphere thicknesses, representative lithological types and their mechanical and thermal properties, rheologies, initial temperature...

  8. Other relevant numerical modelling papers

    International Nuclear Information System (INIS)

    Chartier, M.

    1989-01-01

    The ocean modelling is a rapidly evolving science and a large number of results have been published. Several categories of papers are of particular interest for this review: the papers published by the international atomic institutions, such as the NEA (for the CRESP or Subseabed Programs), the IAEA (for example the Safety Series, the Technical Report Series or the TECDOC), and the ICRP, and the papers concerned by more fundamental research, which are published in specific scientific literature. This paper aims to list some of the most relevant publications for the CRESP purposes. It means by no way to be exhaustive, but informative on the incontestable progress recently achieved in that field. One should note that some of these papers are so recent that their final version has not yet been published

  9. Numerical modelling of elastic space tethers

    DEFF Research Database (Denmark)

    Kristiansen, Kristian Uldall; Palmer, P. L.; Roberts, R. M.

    2012-01-01

    In this paper the importance of the ill-posedness of the classical, non-dissipative massive tether model on an orbiting tether system is studied numerically. The computations document that via the regularisation of bending resistance a more reliable numerical integrator can be produced. Furthermo....... It is also shown that on the slow manifold the dynamics of the satellites are well-approximated by the finite dimensional slack-spring model....

  10. Numerical models of groundwater flow and transport

    International Nuclear Information System (INIS)

    Konikow, L.F.

    1996-01-01

    This chapter reviews the state-of-the-art in deterministic modeling of groundwater flow and transport processes, which can be used for interpretation of isotope data through groundwater flow analyses. Numerical models which are available for this purpose are described and their applications to complex field problems are discussed. The theoretical bases of deterministic modeling are summarized, and advantages and limitations of numerical models are described. The selection of models for specific applications and their calibration procedures are described, and results of a few illustrative case study type applications are provided. (author). 145 refs, 17 figs, 2 tabs

  11. Numerical models of groundwater flow and transport

    Energy Technology Data Exchange (ETDEWEB)

    Konikow, L F [Geological Survey, Reston, VA (United States)

    1996-10-01

    This chapter reviews the state-of-the-art in deterministic modeling of groundwater flow and transport processes, which can be used for interpretation of isotope data through groundwater flow analyses. Numerical models which are available for this purpose are described and their applications to complex field problems are discussed. The theoretical bases of deterministic modeling are summarized, and advantages and limitations of numerical models are described. The selection of models for specific applications and their calibration procedures are described, and results of a few illustrative case study type applications are provided. (author). 145 refs, 17 figs, 2 tabs.

  12. Strategy for a numerical Rock Mechanics Site Descriptive Model. Further development of the theoretical/numerical approach

    International Nuclear Information System (INIS)

    Olofsson, Isabelle; Fredriksson, Anders

    2005-05-01

    The Swedish Nuclear and Fuel Management Company (SKB) is conducting Preliminary Site Investigations at two different locations in Sweden in order to study the possibility of a Deep Repository for spent fuel. In the frame of these Site Investigations, Site Descriptive Models are achieved. These products are the result of an interaction of several disciplines such as geology, hydrogeology, and meteorology. The Rock Mechanics Site Descriptive Model constitutes one of these models. Before the start of the Site Investigations a numerical method using Discrete Fracture Network (DFN) models and the 2D numerical software UDEC was developed. Numerical simulations were the tool chosen for applying the theoretical approach for characterising the mechanical rock mass properties. Some shortcomings were identified when developing the methodology. Their impacts on the modelling (in term of time and quality assurance of results) were estimated to be so important that the improvement of the methodology with another numerical tool was investigated. The theoretical approach is still based on DFN models but the numerical software used is 3DEC. The main assets of the programme compared to UDEC are an optimised algorithm for the generation of fractures in the model and for the assignment of mechanical fracture properties. Due to some numerical constraints the test conditions were set-up in order to simulate 2D plane strain tests. Numerical simulations were conducted on the same data set as used previously for the UDEC modelling in order to estimate and validate the results from the new methodology. A real 3D simulation was also conducted in order to assess the effect of the '2D' conditions in the 3DEC model. Based on the quality of the results it was decided to update the theoretical model and introduce the new methodology based on DFN models and 3DEC simulations for the establishment of the Rock Mechanics Site Descriptive Model. By separating the spatial variability into two parts, one

  13. Analytical and numerical modeling of sandbanks dynamics

    NARCIS (Netherlands)

    Idier, Deborah; Astruc, Dominique

    2003-01-01

    Linear and nonlinear behavior of large-scale underwater bedform patterns like sandbanks are studied using linear stability analysis and numerical modeling. The model is based on depth-integrated hydrodynamics equations with a quadratic bottom friction law and a bed load sediment transport model

  14. Numerical 3-D Modelling of Overflows

    DEFF Research Database (Denmark)

    Larsen, Torben; Nielsen, L.; Jensen, B.

    2008-01-01

    -dimensional so-called Volume of Fluid Models (VOF-models) based on the full Navier-Stokes equations (named NS3 and developed by DHI Water & Environment) As a general conclusion, the two numerical models show excellent results when compared with measurements. However, considerable errors occur when...

  15. Hydrogeological modelling of the eastern region of Areco river locally detailed on Atucha I and II nuclear power plants area

    International Nuclear Information System (INIS)

    Grattone, Natalia I.; Fuentes, Nestor O.

    2009-01-01

    Water flow behaviour of Pampeano aquifer was modeled using Visual Mod-flow software Package 2.8.1 with the assumption of a free aquifer, within the region of the Areco river and extending to the rivers of 'Canada Honda' and 'de la Cruz'. Steady state regime was simulated and grid refinement allows obtaining locally detailed calculation in the area of Atucha I and II Nuclear power plants, in order to compute unsteady situations as the consequence of water flow variations from and to the aquifer, enabling the model to study the movement of possible contaminant particles in the hydrogeologic system. In this work the effects of rivers action, the recharge conditions and the flow lines are analyzed, taking always into account the range of reliability of obtained results, considering the incidence of uncertainties introduced by data input system, the estimates and interpolation of parameters used. (author)

  16. Hydrogeological conditions in the Finnsjoen area. Compilation of data and conceptual model

    International Nuclear Information System (INIS)

    Andersson, J.E.; Nordqvist, R.; Nyberg, G.; Smellie, J.; Tiren, S.

    1991-02-01

    In the present report all available data gathered from the Finnsjoen area of potential use for numerical modelling are compiled and discussed. The data have been collected during different phases during the period 1977-1989. This inevitably means that the quality of the measured and interpreted data varies in accordance with the continuous developments of improved equipments and interpretation techniques. The present report is an updated version of the SKB progress report 89-24 with the same title and authors, see introduction. (au)

  17. Undergraduate Education in Hydrogeology.

    Science.gov (United States)

    Tinker, John Richard, Jr.

    1989-01-01

    Discusses a course at the University of Wisconsin-Eau Claire which improved instruction in physical hydrogeology, chemical hydrogeology, and water resources. Describes 14 laboratory activities including objectives, methods, and a list of equipment needed. (Author/MVL)

  18. Ferrofluids: Modeling, numerical analysis, and scientific computation

    Science.gov (United States)

    Tomas, Ignacio

    This dissertation presents some developments in the Numerical Analysis of Partial Differential Equations (PDEs) describing the behavior of ferrofluids. The most widely accepted PDE model for ferrofluids is the Micropolar model proposed by R.E. Rosensweig. The Micropolar Navier-Stokes Equations (MNSE) is a subsystem of PDEs within the Rosensweig model. Being a simplified version of the much bigger system of PDEs proposed by Rosensweig, the MNSE are a natural starting point of this thesis. The MNSE couple linear velocity u, angular velocity w, and pressure p. We propose and analyze a first-order semi-implicit fully-discrete scheme for the MNSE, which decouples the computation of the linear and angular velocities, is unconditionally stable and delivers optimal convergence rates under assumptions analogous to those used for the Navier-Stokes equations. Moving onto the much more complex Rosensweig's model, we provide a definition (approximation) for the effective magnetizing field h, and explain the assumptions behind this definition. Unlike previous definitions available in the literature, this new definition is able to accommodate the effect of external magnetic fields. Using this definition we setup the system of PDEs coupling linear velocity u, pressure p, angular velocity w, magnetization m, and magnetic potential ϕ We show that this system is energy-stable and devise a numerical scheme that mimics the same stability property. We prove that solutions of the numerical scheme always exist and, under certain simplifying assumptions, that the discrete solutions converge. A notable outcome of the analysis of the numerical scheme for the Rosensweig's model is the choice of finite element spaces that allow the construction of an energy-stable scheme. Finally, with the lessons learned from Rosensweig's model, we develop a diffuse-interface model describing the behavior of two-phase ferrofluid flows and present an energy-stable numerical scheme for this model. For a

  19. Compilation of data used for the analysis of the geological and hydrogeological DFN models. Site descriptive modelling SDM-Site Laxemar

    International Nuclear Information System (INIS)

    Hermanson, Jan; Fox, Aaron; Oehman, Johan; Rhen, Ingvar

    2008-08-01

    This report provides an overview and compilation of the various data that constitutes the basis for construction of the geological and hydrogeological discrete feature network (DFN) models as part of model version SDM-Site Laxemar. This includes a review of fracture data in boreholes and in outcrop. Furthermore, the basis for the construction of lineament maps is given as well as a review of the hydraulic test data from cored and percussion-drilled boreholes. An emphasis is put on graphical representation of borehole logs in the form of composites of geological, hydrogeological and even hydrogeochemical data in the case of cored boreholes. One major contribution is a compilation of characteristics of minor local deformation zones (MDZs) identified in cored boreholes. Basic orientation data and fracture intensity data are presented as a function of depth for individual boreholes. The coupling between hydrogeological data and geological data is further refined in plots of Posiva flow log (PFL) data vs. geological single hole interpretation data

  20. Comparing numerically exact and modelled static friction

    Directory of Open Access Journals (Sweden)

    Krengel Dominik

    2017-01-01

    Full Text Available Currently there exists no mechanically consistent “numerically exact” implementation of static and dynamic Coulomb friction for general soft particle simulations with arbitrary contact situations in two or three dimension, but only along one dimension. We outline a differential-algebraic equation approach for a “numerically exact” computation of friction in two dimensions and compare its application to the Cundall-Strack model in some test cases.

  1. Reactor Thermal Hydraulic Numerical Calculation And Modeling

    International Nuclear Information System (INIS)

    Duong Ngoc Hai; Dang The Ba

    2008-01-01

    In the paper the results of analysis of thermal hydraulic state models using the numerical codes such as COOLOD, EUREKA and RELAP5 for simulation of the reactor thermal hydraulic states are presented. The calculations, analyses of reactor thermal hydraulic state and safety were implemented using different codes. The received numerical results, which were compared each to other, to experiment measurement of Dalat (Vietnam) research reactor and published results, show their appropriateness and capacity for analyses of different appropriate cases. (author)

  2. Meteorological, hydrological and hydrogeological monitoring data and near-surface hydrogeological properties data from Laxemar-Simpevarp. Site descriptive modelling SDM-Site Laxemar

    International Nuclear Information System (INIS)

    Werner, Kent; Oehman, Johan; Holgersson, Bjoern; Roennback, Kristoffer; Marelius, Fredrick

    2008-12-01

    This report presents and analyses meteorological, hydrological and hydrogeological time-series data and near-surface hydrogeological properties data from the Laxemar-Simpevarp area, available in SKB's Sicada database at time of the Laxemar 2.3 data freeze (Aug. 31, 2007). The meteorological data set includes data from two local stations, located on the island of Aespoe and at Plittorp, located further inland. In addition, the data evaluation uses a longer-term data set from 7 surrounding stations, operated by SMHI. As part of this study, a time series is constructed of the water content of snow. According to the data evaluation, the site-average annual precipitation and potential evapotranspiration can be estimated to be on the order of 600 and 535 mm, respectively. In particular, precipitation demonstrates a near-coastal gradient, with less precipitation at the coast compared to areas further inland. The surface-water level data set includes data from 4 lake-level gauging stations and 3 sea-level gauging stations. All lakes are located above sea level, including the near-coastal Lake Soeraa. Hence, no intrusion of sea water to lakes takes place. There is a strong co-variation among the monitored lake-water levels, typically with maxima during spring and minima during late summer and early autumn. Concerning the sea as a hydraulic boundary, the maximum and minimum sea levels (daily averages) during the site-investigation period were -0.52 and 0.71 metres above sea level, respectively, whereas the average sea level was 0.03 metres above sea level (RHB 70). The data set on stream discharge, surface-water temperature and electrical conductivity includes data from 9 discharge-gauging stations in 7 streams. Based on the discharge data, the site-average specific discharge for the years 2005-2007 can be estimated to 165 mm/y, which is within the interval of the estimated long-term average. Overall, discharge-data errors are likely to be small. The hydrogeological time

  3. Numerical Modeling of Ablation Heat Transfer

    Science.gov (United States)

    Ewing, Mark E.; Laker, Travis S.; Walker, David T.

    2013-01-01

    A unique numerical method has been developed for solving one-dimensional ablation heat transfer problems. This paper provides a comprehensive description of the method, along with detailed derivations of the governing equations. This methodology supports solutions for traditional ablation modeling including such effects as heat transfer, material decomposition, pyrolysis gas permeation and heat exchange, and thermochemical surface erosion. The numerical scheme utilizes a control-volume approach with a variable grid to account for surface movement. This method directly supports implementation of nontraditional models such as material swelling and mechanical erosion, extending capabilities for modeling complex ablation phenomena. Verifications of the numerical implementation are provided using analytical solutions, code comparisons, and the method of manufactured solutions. These verifications are used to demonstrate solution accuracy and proper error convergence rates. A simple demonstration of a mechanical erosion (spallation) model is also provided to illustrate the unique capabilities of the method.

  4. Numerical methods and modelling for engineering

    CERN Document Server

    Khoury, Richard

    2016-01-01

    This textbook provides a step-by-step approach to numerical methods in engineering modelling. The authors provide a consistent treatment of the topic, from the ground up, to reinforce for students that numerical methods are a set of mathematical modelling tools which allow engineers to represent real-world systems and compute features of these systems with a predictable error rate. Each method presented addresses a specific type of problem, namely root-finding, optimization, integral, derivative, initial value problem, or boundary value problem, and each one encompasses a set of algorithms to solve the problem given some information and to a known error bound. The authors demonstrate that after developing a proper model and understanding of the engineering situation they are working on, engineers can break down a model into a set of specific mathematical problems, and then implement the appropriate numerical methods to solve these problems. Uses a “building-block” approach, starting with simpler mathemati...

  5. On the Hughes model and numerical aspects

    KAUST Repository

    Gomes, Diogo A.

    2017-01-05

    We study a crowd model proposed by R. Hughes in [11] and we describe a numerical approach to solve it. This model comprises a Fokker-Planck equation coupled with an eikonal equation with Dirichlet or Neumann data. First, we establish a priori estimates for the solutions. Second, we study radial solutions and identify a shock formation mechanism. Third, we illustrate the existence of congestion, the breakdown of the model, and the trend to the equilibrium. Finally, we propose a new numerical method and consider two examples.

  6. On the Hughes model and numerical aspects

    KAUST Repository

    Gomes, Diogo A.; Machado Velho, Roberto

    2017-01-01

    We study a crowd model proposed by R. Hughes in [11] and we describe a numerical approach to solve it. This model comprises a Fokker-Planck equation coupled with an eikonal equation with Dirichlet or Neumann data. First, we establish a priori

  7. Volcanic aquifers of Hawai‘i—Hydrogeology, water budgets, and conceptual models

    Science.gov (United States)

    Izuka, Scot K.; Engott, John A.; Rotzoll, Kolja; Bassiouni, Maoya; Johnson, Adam G.; Miller, Lisa D.; Mair, Alan

    2016-06-13

    Hawai‘i’s aquifers have limited capacity to store fresh groundwater because each island is small and surrounded by saltwater. Saltwater also underlies much of the fresh groundwater. Fresh groundwater resources are, therefore, particularly vulnerable to human activity, short-term climate cycles, and long-term climate change. Availability of fresh groundwater for human use is constrained by the degree to which the impacts of withdrawal—such as lowering of the water table, saltwater intrusion, and reduction in the natural discharge to springs, streams, wetlands, and submarine seeps—are deemed acceptable. This report describes the hydrogeologic framework, groundwater budgets (inflows and outflows), conceptual models of groundwater occurrence and movement, and the factors limiting groundwater availability for the largest and most populated of the Hawaiian Islands—Kaua‘i, O‘ahu, Maui, and Hawai‘i Island.The bulk of each of Hawai‘i’s islands is built of many thin lava flows erupted from shield volcanoes; the great piles of lava flows form highly permeable aquifers. In some areas, low-permeability dikes cutting across the lava flows, or low-permeability ash and soil horizons interlayered with the lava flows, can substantially alter groundwater flow. On some islands, sedimentary rocks form thick semiconfining coastal-plain deposits, locally known as caprock, that impede natural groundwater discharge to the ocean. In some regions, thick lava flows that ponded in preexisting depressions form aquifers that are much less permeable than aquifers formed by thin lava flows.Fresh groundwater inflow to Hawai‘i’s aquifers comes from recharge. For predevelopment conditions (1870), estimates of groundwater recharge from this study are 871, 675, 1,279, and 5,291 million gallons per day (Mgal/d) for Kaua‘i, O‘ahu, Maui, and Hawai‘i Island, respectively. Estimates of recharge for recent conditions (2010 land cover and 1978–2007 rainfall for Kaua‘i, O

  8. Modeling of 3d Space-time Surface of Potential Fields and Hydrogeologic Modeling of Nuclear Waste Disposal Sites

    Science.gov (United States)

    Shestopalov, V.; Bondarenko, Y.; Zayonts, I.; Rudenko, Y.

    extension and consolidation are identified. These data correlate with results of seismic and mining works. Hydrogeological 3D Model. The hydrogeological 3D Model de- velopment starts from the upper hydrodynamic zone, for which the data are available on hydraulic parameters. After calibration of the upper model elements, the deep part of the model is developed using data about the permeability structure of the crystalline rock massif, obtained from the 3D STSM. The results of analysis and the discrepancy of hydrodynamic regime modeling are used to refine the 3D Model for the rocks per- meability structure. This iterative process of consecutive correlation and refinement of model may be repeated many times. As a result of this technique implementation, the areas of active and very slow water exchange are found, and the system is revealed of vertically alternating zones of enhanced filtration and weak permeability. Based on these data, the sites are pre-selected, which are prospective for subsequently more detailed works on grounding the possibility of nuclear wastes isolation in geological formations. The use of the methodology described above is expedient at the stage of more detailed works, if the corresponding complex is provided of geophysical, hydro- geological, field testing and modeling investigations. Summary Successful testing of 3D STSM technology was carried out starting from 1997 till 1999 by the Ministry of Emergency Situations and Nuclear Safety of Ukraine during the realization of the project "Choosing the favorable geological structures for safe isolation of dangerous nuclear wastes of Chernobyl NPP". The performed works enabled us to draw prelim- inary 3D Space-Time Surface Model, structural-kinematic and geodynamic map of 2 the region understudy. As a result, two regions were selected, which are characterized by existence of geodynamic processes of cooling, thermal shrinkage and structural substance compression of geospace medium. Such regions seem to be the

  9. Meteorological, hydrological and hydrogeological monitoring data and near-surface hydrogeological properties data from Laxemar-Simpevarp. Site descriptive modelling SDM-Site Laxemar

    Energy Technology Data Exchange (ETDEWEB)

    Werner, Kent (EmpTec, Taeby (Sweden)); Oehman, Johan (Golder Associates AB, Stockholm (Sweden)); Holgersson, Bjoern (SWECO VIAK, Stockholm (Sweden)); Roennback, Kristoffer (Aqualog AB, Goeteborg (Sweden)); Marelius, Fredrick (WSP Sverige, Stockholm (Sweden))

    2008-12-15

    This report presents and analyses meteorological, hydrological and hydrogeological time-series data and near-surface hydrogeological properties data from the Laxemar-Simpevarp area, available in SKB's Sicada database at time of the Laxemar 2.3 data freeze (Aug. 31, 2007). The meteorological data set includes data from two local stations, located on the island of Aespoe and at Plittorp, located further inland. In addition, the data evaluation uses a longer-term data set from 7 surrounding stations, operated by SMHI. As part of this study, a time series is constructed of the water content of snow. According to the data evaluation, the site-average annual precipitation and potential evapotranspiration can be estimated to be on the order of 600 and 535 mm, respectively. In particular, precipitation demonstrates a near-coastal gradient, with less precipitation at the coast compared to areas further inland. The surface-water level data set includes data from 4 lake-level gauging stations and 3 sea-level gauging stations. All lakes are located above sea level, including the near-coastal Lake Soeraa. Hence, no intrusion of sea water to lakes takes place. There is a strong co-variation among the monitored lake-water levels, typically with maxima during spring and minima during late summer and early autumn. Concerning the sea as a hydraulic boundary, the maximum and minimum sea levels (daily averages) during the site-investigation period were -0.52 and 0.71 metres above sea level, respectively, whereas the average sea level was 0.03 metres above sea level (RHB 70). The data set on stream discharge, surface-water temperature and electrical conductivity includes data from 9 discharge-gauging stations in 7 streams. Based on the discharge data, the site-average specific discharge for the years 2005-2007 can be estimated to 165 mm/y, which is within the interval of the estimated long-term average. Overall, discharge-data errors are likely to be small. The hydrogeological

  10. Resource modelling for control: how hydrogeological modelling can support a water quality monitoring infrastructure

    Science.gov (United States)

    Scozzari, Andrea; Doveri, Marco

    2015-04-01

    The knowledge of the physical/chemical processes implied with the exploitation of water bodies for human consumption is an essential tool for the optimisation of the monitoring infrastructure. Due to their increasing importance in the context of human consumption (at least in the EU), this work focuses on groundwater resources. In the framework of drinkable water networks, the physical and data-driven modelling of transport phenomena in groundwater can help optimising the sensor network and validating the acquired data. This work proposes the combined usage of physical and data-driven modelling as a support to the design and maximisation of results from a network of distributed sensors. In particular, the validation of physico-chemical measurements and the detection of eventual anomalies by a set of continuous measurements take benefit from the knowledge of the domain from which water is abstracted, and its expected characteristics. Change-detection techniques based on non-specific sensors (presented by quite a large literature during the last two decades) have to deal with the classical issues of maximising correct detections and minimising false alarms, the latter of the two being the most typical problem to be faced, in the view of designing truly applicable monitoring systems. In this context, the definition of "anomaly" in terms of distance from an expected value or feature characterising the quality of water implies the definition of a suitable metric and the knowledge of the physical and chemical peculiarities of the natural domain from which water is exploited, with its implications in terms of characteristics of the water resource.

  11. Fundamentals of Numerical Modelling of Casting Processes

    DEFF Research Database (Denmark)

    Hattel, Jesper Henri; Pryds, Nini; Thorborg, Jesper

    Fundamentals of Numerical Modelling of Casting Processes comprises a thorough presentation of the basic phenomena that need to be addressed in numerical simulation of casting processes. The main philosophy of the book is to present the topics in view of their physical meaning, whenever possible......, rather than relying strictly on mathematical formalism. The book, aimed both at the researcher and the practicing engineer, as well as the student, is naturally divided into four parts. Part I (Chapters 1-3) introduces the fundamentals of modelling in a 1-dimensional framework. Part II (Chapter 4...

  12. Numerical modeling techniques for flood analysis

    Science.gov (United States)

    Anees, Mohd Talha; Abdullah, K.; Nawawi, M. N. M.; Ab Rahman, Nik Norulaini Nik; Piah, Abd. Rahni Mt.; Zakaria, Nor Azazi; Syakir, M. I.; Mohd. Omar, A. K.

    2016-12-01

    Topographic and climatic changes are the main causes of abrupt flooding in tropical areas. It is the need to find out exact causes and effects of these changes. Numerical modeling techniques plays a vital role for such studies due to their use of hydrological parameters which are strongly linked with topographic changes. In this review, some of the widely used models utilizing hydrological and river modeling parameters and their estimation in data sparse region are discussed. Shortcomings of 1D and 2D numerical models and the possible improvements over these models through 3D modeling are also discussed. It is found that the HEC-RAS and FLO 2D model are best in terms of economical and accurate flood analysis for river and floodplain modeling respectively. Limitations of FLO 2D in floodplain modeling mainly such as floodplain elevation differences and its vertical roughness in grids were found which can be improve through 3D model. Therefore, 3D model was found to be more suitable than 1D and 2D models in terms of vertical accuracy in grid cells. It was also found that 3D models for open channel flows already developed recently but not for floodplain. Hence, it was suggested that a 3D model for floodplain should be developed by considering all hydrological and high resolution topographic parameter's models, discussed in this review, to enhance the findings of causes and effects of flooding.

  13. A spatial DB model to simulate the road network efficiency in hydrogeological emergency

    Science.gov (United States)

    Michele, Mangiameli; Giuseppe, Mussumeci

    2015-12-01

    We deal with the theme of the simulation of risk analysis using a technological approach based on the integration of exclusively free and open source tools: PostgreSQL as Database Management System (DBMS) and Quantum GIS-GRASS as Geographic Information System (GIS) platform. The case study is represented by a seismic land in Sicily characterized by steep slopes and frequent instability phenomena. This area includes a city of about 30.000 inhabitants (Enna) that lies on the top of a mountain at about 990 m a.s.l.. The access to the city is assured by few and very winding roads that are also highly vulnerable to seismic and hydrogeological hazards. When exceptional rainfall events occur, the loss of efficiency of these roads should compromise timeliness and effectiveness of rescue operations. The data of the sample area have been structured into the adopted DBMS, and the connection to the GIS functionalities allows simulating the exceptional events. We analyzed the hazard, vulnerability and exposure related to these events and calculated the final risk defining three classes for each scenario: low (L), medium (M) and high (H). This study can be a valuable tool to prioritize risk levels and set priorities for intervention to the main road networks..

  14. A spatial DB model to simulate the road network efficiency in hydrogeological emergency

    Energy Technology Data Exchange (ETDEWEB)

    Michele, Mangiameli, E-mail: michele.mangiameli@dica.unict.it; Giuseppe, Mussumeci [Dept. of Civil Engineering and Architecture, University of Catania, Catania (Italy)

    2015-12-31

    We deal with the theme of the simulation of risk analysis using a technological approach based on the integration of exclusively free and open source tools: PostgreSQL as Database Management System (DBMS) and Quantum GIS-GRASS as Geographic Information System (GIS) platform. The case study is represented by a seismic land in Sicily characterized by steep slopes and frequent instability phenomena. This area includes a city of about 30.000 inhabitants (Enna) that lies on the top of a mountain at about 990 m a.s.l.. The access to the city is assured by few and very winding roads that are also highly vulnerable to seismic and hydrogeological hazards. When exceptional rainfall events occur, the loss of efficiency of these roads should compromise timeliness and effectiveness of rescue operations. The data of the sample area have been structured into the adopted DBMS, and the connection to the GIS functionalities allows simulating the exceptional events. We analyzed the hazard, vulnerability and exposure related to these events and calculated the final risk defining three classes for each scenario: low (L), medium (M) and high (H). This study can be a valuable tool to prioritize risk levels and set priorities for intervention to the main road networks.

  15. A spatial DB model to simulate the road network efficiency in hydrogeological emergency

    International Nuclear Information System (INIS)

    Michele, Mangiameli; Giuseppe, Mussumeci

    2015-01-01

    We deal with the theme of the simulation of risk analysis using a technological approach based on the integration of exclusively free and open source tools: PostgreSQL as Database Management System (DBMS) and Quantum GIS-GRASS as Geographic Information System (GIS) platform. The case study is represented by a seismic land in Sicily characterized by steep slopes and frequent instability phenomena. This area includes a city of about 30.000 inhabitants (Enna) that lies on the top of a mountain at about 990 m a.s.l.. The access to the city is assured by few and very winding roads that are also highly vulnerable to seismic and hydrogeological hazards. When exceptional rainfall events occur, the loss of efficiency of these roads should compromise timeliness and effectiveness of rescue operations. The data of the sample area have been structured into the adopted DBMS, and the connection to the GIS functionalities allows simulating the exceptional events. We analyzed the hazard, vulnerability and exposure related to these events and calculated the final risk defining three classes for each scenario: low (L), medium (M) and high (H). This study can be a valuable tool to prioritize risk levels and set priorities for intervention to the main road networks.

  16. SITE-94. Discrete-feature modelling of the Aespoe Site: 3. Predictions of hydrogeological parameters for performance assessment

    International Nuclear Information System (INIS)

    Geier, J.E.

    1996-12-01

    A 3-dimensional, discrete-feature hydrological model is developed. The model integrates structural and hydrologic data for the Aespoe site, on scales ranging from semi regional fracture zones to individual fractures in the vicinity of the nuclear waste canisters. Predicted parameters for the near field include fracture spacing, fracture aperture, and Darcy velocity at each of forty canister deposition holes. Parameters for the far field include discharge location, Darcy velocity, effective longitudinal dispersion coefficient and head gradient, flow porosity, and flow wetted surface, for each canister source that discharges to the biosphere. Results are presented in the form of statistical summaries for a total of 42 calculation cases, which treat a set of 25 model variants in various combinations. The variants for the SITE-94 Reference Case model address conceptual and parametric uncertainty related to the site-scale hydrogeologic model and its properties, the fracture network within the repository, effective semi regional boundary conditions for the model, and the disturbed-rock zone around the repository tunnels and shafts. Two calculation cases simulate hydrologic conditions that are predicted to occur during future glacial episodes. 30 refs

  17. Basset force in numerical models of saltation

    Czech Academy of Sciences Publication Activity Database

    Lukerchenko, Nikolay; Dolanský, Jindřich; Vlasák, Pavel

    2012-01-01

    Roč. 60, č. 4 (2012), s. 277-287 ISSN 0042-790X R&D Projects: GA ČR GA103/09/1718 Institutional research plan: CEZ:AV0Z20600510 Keywords : basset force * bed load transport * numerical model * particle-bed collision Subject RIV: BK - Fluid Dynamics Impact factor: 0.653, year: 2012

  18. Thin sheet numerical modelling of continental collision

    NARCIS (Netherlands)

    Jimenez-Munt, I.; Garcia-Gastellanos, D.; Fernandez, M.

    2005-01-01

    We study the effects of incorporating surface mass transport and the gravitational potential energy of both crust and lithospheric mantle to the viscous thin sheet approach. Recent 2D (cross-section) numerical models show that surface erosion and sediment transport can play a major role in shaping

  19. Numerical modelling of steel arc welding

    International Nuclear Information System (INIS)

    Hamide, M.

    2008-07-01

    Welding is a highly used assembly technique. Welding simulation software would give access to residual stresses and information about the weld's microstructure, in order to evaluate the mechanical resistance of a weld. It would also permit to evaluate the process feasibility when complex geometrical components are to be made, and to optimize the welding sequences in order to minimize defects. This work deals with the numerical modelling of arc welding process of steels. After describing the industrial context and the state of art, the models implemented in TransWeld (software developed at CEMEF) are presented. The set of macroscopic equations is followed by a discussion on their numerical implementation. Then, the theory of re-meshing and our adaptive anisotropic re-meshing strategy are explained. Two welding metal addition techniques are investigated and are compared in terms of the joint size and transient temperature and stresses. The accuracy of the finite element model is evaluated based on experimental results and the results of the analytical solution. Comparative analysis between experimental and numerical results allows the assessment of the ability of the numerical code to predict the thermomechanical and metallurgical response of the welded structure. The models limitations and the phenomena identified during this study are finally discussed and permit to define interesting orientations for future developments. (author)

  20. Numerical modeling of magma-repository interactions

    NARCIS (Netherlands)

    Bokhove, Onno

    2001-01-01

    This report explains the numerical programs behind a comprehensive modeling effort of magma-repository interactions. Magma-repository interactions occur when a magma dike with high-volatile content magma ascends through surrounding rock and encounters a tunnel or drift filled with either a magmatic

  1. Graphical interpretation of numerical model results

    International Nuclear Information System (INIS)

    Drewes, D.R.

    1979-01-01

    Computer software has been developed to produce high quality graphical displays of data from a numerical grid model. The code uses an existing graphical display package (DISSPLA) and overcomes some of the problems of both line-printer output and traditional graphics. The software has been designed to be flexible enough to handle arbitrarily placed computation grids and a variety of display requirements

  2. Adaptive numerical modeling of dynamic crack propagation

    International Nuclear Information System (INIS)

    Adouani, H.; Tie, B.; Berdin, C.; Aubry, D.

    2006-01-01

    We propose an adaptive numerical strategy that aims at developing reliable and efficient numerical tools to model dynamic crack propagation and crack arrest. We use the cohesive zone theory as behavior of interface-type elements to model crack. Since the crack path is generally unknown beforehand, adaptive meshing is proposed to model the dynamic crack propagation. The dynamic study requires the development of specific solvers for time integration. As both geometry and finite element mesh of the studied structure evolve in time during transient analysis, the stability behavior of dynamic solver becomes a major concern. For this purpose, we use the space-time discontinuous Galerkin finite element method, well-known to provide a natural framework to manage meshes that evolve in time. As an important result, we prove that the space-time discontinuous Galerkin solver is unconditionally stable, when the dynamic crack propagation is modeled by the cohesive zone theory, which is highly non-linear. (authors)

  3. Numerical modelling in non linear fracture mechanics

    Directory of Open Access Journals (Sweden)

    Viggo Tvergaard

    2007-07-01

    Full Text Available Some numerical studies of crack propagation are based on using constitutive models that accountfor damage evolution in the material. When a critical damage value has been reached in a materialpoint, it is natural to assume that this point has no more carrying capacity, as is done numerically in the elementvanish technique. In the present review this procedure is illustrated for micromechanically based materialmodels, such as a ductile failure model that accounts for the nucleation and growth of voids to coalescence, and a model for intergranular creep failure with diffusive growth of grain boundary cavities leading to micro-crack formation. The procedure is also illustrated for low cycle fatigue, based on continuum damage mechanics. In addition, the possibility of crack growth predictions for elastic-plastic solids using cohesive zone models to represent the fracture process is discussed.

  4. A conceptual model of the hydrogeologic framework, geochemistry, and groundwater-flow system of the Edwards-Trinity and related aquifers in the Pecos County region, Texas

    Science.gov (United States)

    Bumgarner, Johnathan R.; Stanton, Gregory P.; Teeple, Andrew; Thomas, Jonathan V.; Houston, Natalie A.; Payne, Jason; Musgrove, MaryLynn

    2012-01-01

    A conceptual model of the hydrogeologic framework, geochemistry, and groundwater-flow system of the Edwards-Trinity and related aquifers, which include the Pecos Valley, Igneous, Dockum, Rustler, and Capitan Reef aquifers, was developed as the second phase of a groundwater availability study in the Pecos County region in west Texas. The first phase of the study was to collect and compile groundwater, surface-water, water-quality, geophysical, and geologic data in the area. The third phase of the study involves a numerical groundwater-flow model of the Edwards-Trinity aquifer in order to simulate groundwater conditions based on various groundwater-withdrawal scenarios. Resource managers plan to use the results of the study to establish management strategies for the groundwater system. The hydrogeologic framework is composed of the hydrostratigraphy, structural features, and hydraulic properties of the groundwater system. Well and geophysical logs were interpreted to define the top and base surfaces of the Edwards-Trinity aquifer units. Elevations of the top and base of the Edwards-Trinity aquifer generally decrease from the southwestern part of the study area to the northeast. The thicknesses of the Edwards-Trinity aquifer units were calculated using the interpolated top and base surfaces of the hydrostratigraphic units. Some of the thinnest sections of the aquifer were in the eastern part of the study area and some of the thickest sections were in the Pecos, Monument Draw, and Belding-Coyanosa trough areas. Normal-fault zones, which formed as growth and collapse features as sediments were deposited along the margins of more resistant rocks and as overlying sediments collapsed into the voids created by the dissolution of Permian-age evaporite deposits, were delineated based on the interpretation of hydrostratigraphic cross sections. The lowest aquifer transmissivity values were measured in the eastern part of the study area; the highest transmissivity values were

  5. Hydrogeological modeling constraints provided by geophysical and geochemical mapping of a chlorinated ethenes plume in northern France

    Science.gov (United States)

    Razafindratsima, Stephen; Guérin, Roger; Bendjoudi, Hocine; de Marsily, Ghislain

    2014-09-01

    A methodological approach is described which combines geophysical and geochemical data to delineate the extent of a chlorinated ethenes plume in northern France; the methodology was used to calibrate a hydrogeological model of the contaminants' migration and degradation. The existence of strong reducing conditions in some parts of the aquifer is first determined by measuring in situ the redox potential and dissolved oxygen, dissolved ferrous iron and chloride concentrations. Electrical resistivity imaging and electromagnetic mapping, using the Slingram method, are then used to determine the shape of the pollutant plume. A decreasing empirical exponential relation between measured chloride concentrations in the water and aquifer electrical resistivity is observed; the resistivity formation factor calculated at a few points also shows a major contribution of chloride concentration in the resistivity of the saturated porous medium. MODFLOW software and MT3D99 first-order parent-daughter chain reaction and the RT3D aerobic-anaerobic model for tetrachloroethene (PCE)/trichloroethene (TCE) dechlorination are finally used for a first attempt at modeling the degradation of the chlorinated ethenes. After calibration, the distribution of the chlorinated ethenes and their degradation products simulated with the model approximately reflects the mean measured values in the observation wells, confirming the data-derived image of the plume.

  6. Numerical modeling of fires on gas pipelines

    International Nuclear Information System (INIS)

    Zhao Yang; Jianbo Lai; Lu Liu

    2011-01-01

    When natural gas is released through a hole on a high-pressure pipeline, it disperses in the atmosphere as a jet. A jet fire will occur when the leaked gas meets an ignition source. To estimate the dangerous area, the shape and size of the fire must be known. The evolution of the jet fire in air is predicted by using a finite-volume procedure to solve the flow equations. The model is three-dimensional, elliptic and calculated by using a compressibility corrected version of the k - ξ turbulence model, and also includes a probability density function/laminar flamelet model of turbulent non-premixed combustion process. Radiation heat transfer is described using an adaptive version of the discrete transfer method. The model is compared with the experiments about a horizontal jet fire in a wind tunnel in the literature with success. The influence of wind and jet velocity on the fire shape has been investigated. And a correlation based on numerical results for predicting the stoichiometric flame length is proposed. - Research highlights: → We developed a model to predict the evolution of turbulent jet diffusion flames. → Measurements of temperature distributions match well with the numerical predictions. → A correlation has been proposed to predict the stoichiometric flame length. → Buoyancy effects are higher in the numerical results. → The radiative heat loss is bigger in the experimental results.

  7. Numerical Modelling Of Pumpkin Balloon Instability

    Science.gov (United States)

    Wakefield, D.

    Tensys have been involved in the numerical formfinding and load analysis of architectural stressed membrane structures for 15 years. They have recently broadened this range of activities into the `lighter than air' field with significant involvement in aerostat and heavy-lift hybrid airship design. Since early 2004 they have been investigating pumpkin balloon instability on behalf of the NASA ULDB programme. These studies are undertaken using inTENS, an in-house finite element program suite based upon the Dynamic Relaxation solution method and developed especially for the non-linear analysis and patterning of membrane structures. The paper describes the current state of an investigation that started with a numerical simulation of the lobed cylinder problem first studied by Calladine. The influence of material properties and local geometric deformation on stability is demonstrated. A number of models of complete pumpkin balloons have then been established, including a 64-gore balloon with geometry based upon Julian Nott's Endeavour. This latter clefted dramatically upon initial inflation, a phenomenon that has been reproduced in the numerical model. Ongoing investigations include the introduction of membrane contact modelling into inTENS and correlation studies with the series of large-scale ULDB models currently in preparation.

  8. Numerical Modeling of Piezoelectric Transducers Using Physical Parameters

    NARCIS (Netherlands)

    Cappon, H.; Keesman, K.J.

    2012-01-01

    Design of ultrasonic equipment is frequently facilitated with numerical models. These numerical models, however, need a calibration step, because usually not all characteristics of the materials used are known. Characterization of material properties combined with numerical simulations and

  9. Geological investigations and hydrogeologic model development in support of DoD and DOE environmental programs on Kirtland Air Force Base, New Mexico, U.S.A

    International Nuclear Information System (INIS)

    Gibson, J.D.; Pratt, G.; Davidson, H.; DeWitt, C.; Hitchcock, C.; Kelson, K.; Noller, J.; Sawyer, T.; Thomas, E.

    1994-01-01

    This paper presents results of preliminary geologic site characterization and hydrogeologic conceptual model development for the 250-km 2 Kirtland Air Force Base (KAFB) and associated lands in central New Mexico. The research, development, and other operational activities of the Department of Defense (DoD) and Department of Energy (DOE) on KAFB over the last 50 years have resulted in diverse hazardous, radioactive, and mixed-waste environmental concerns. Because multiple federal, state, and local agencies are responsible for administrating the involved lands and because of the nature of many U.S. environmental regulations, individual contaminated and potentially contaminated DoD and DOE environmental restoration (ER) sites on KAFB are commonly handled as distinct entities with little consideration for the cumulative environmental and health risk from all sites. A site-wide characterization program has been undertaken at Sandia National Laboratories/New Mexico (SNL/NM), under the auspices of the DOE, to construct a conceptual hydrogeologic model for the base. This conceptual model serves as the basis for placing each ER site into a broader context for evaluating background (i.e., non-contaminated) conditions and for modeling of possible contaminant pathways and travel-times. Regional and local hydrogeologic investigations from KAFB can be used as models for characterizing and evaluating other sites around the world where combined civilian and military environmental programs must work together to resolve environmental problems that may present health risks to workers and the general public

  10. Numerical modeling in materials science and engineering

    CERN Document Server

    Rappaz, Michel; Deville, Michel

    2003-01-01

    This book introduces the concepts and methodologies related to the modelling of the complex phenomena occurring in materials processing. After a short reminder of conservation laws and constitutive relationships, the authors introduce the main numerical methods: finite differences, finite volumes and finite elements. These techniques are developed in three main chapters of the book that tackle more specific problems: phase transformation, solid mechanics and fluid flow. The two last chapters treat inverse methods to obtain the boundary conditions or the material properties and stochastic methods for microstructural simulation. This book is intended for undergraduate and graduate students in materials science and engineering, mechanical engineering and physics and for engineering professionals or researchers who want to get acquainted with numerical simulation to model and compute materials processing.

  11. Lattice Boltzmann model for numerical relativity.

    Science.gov (United States)

    Ilseven, E; Mendoza, M

    2016-02-01

    In the Z4 formulation, Einstein equations are written as a set of flux conservative first-order hyperbolic equations that resemble fluid dynamics equations. Based on this formulation, we construct a lattice Boltzmann model for numerical relativity and validate it with well-established tests, also known as "apples with apples." Furthermore, we find that by increasing the relaxation time, we gain stability at the cost of losing accuracy, and by decreasing the lattice spacings while keeping a constant numerical diffusivity, the accuracy and stability of our simulations improve. Finally, in order to show the potential of our approach, a linear scaling law for parallelization with respect to number of CPU cores is demonstrated. Our model represents the first step in using lattice kinetic theory to solve gravitational problems.

  12. An integrated theoretical and practical approach for teaching hydrogeology

    Science.gov (United States)

    Bonomi, Tullia; Fumagalli, Letizia; Cavallin, Angelo

    2013-04-01

    Hydrogeology as an earth science intersects the broader disciplines of geology, engineering, and environmental studies but it does not overlap fully with any of them. It is focused on its own range of problems and over time has developed a rich variety of methods and approaches. The resolution of many hydrogeological problems requires knowledge of elements of geology, hydraulics, physics and chemistry; moreover in recent years the knowledge of modelling techniques has become a necessary ability. Successful transfer of all this knowledge to the students depends on the breadth of material taught in courses, the natural skills of the students and any practical experience the students can obtain. In the Department of Earth and Environmental Sciences of the University of Milano-Bicocca, the teaching of hydrogeology is developed in three inter-related courses: 1) general hydrogeology, 2) applied hydrogeology, 3) groundwater pollution and remediation. The sequence focuses on both groundwater flux and contaminant transport, supplemented by workshops involving case studies and computer labs, which provide the students with practical translation of the theoretical aspects of the science into the world of work. A second key aspect of the program utilizes the students' skill at learning through online approaches, and this is done through three approaches: A) by developing the courses on a University e-learning platform that allows the students to download lectures, articles, and teacher comments, and to participate in online forums; B) by carring out exercises through computer labs where the student analyze and process hydrogeological data by means of different numerical codes, that in turn enable them to manage databases and to perform aquifer test analysis, geostatistical analysis, and flux and transport modelling both in the unsaturated and saturated zone. These exercises are of course preceded by theoretical lectures on codes and software, highlighting their features and

  13. Sensitivity analysis and development of calibration methodology for near-surface hydrogeology model of Forsmark

    International Nuclear Information System (INIS)

    Aneljung, Maria; Gustafsson, Lars-Goeran

    2007-04-01

    The hydrological modelling system MIKE SHE has been used to describe near-surface groundwater flow, transport mechanisms and the contact between ground- and surface water at the Forsmark site. The surface water system at Forsmark is described with the 1D modelling tool MIKE 11, which is fully and dynamically integrated with MIKE SHE. In spring 2007, a new data freeze will be available and a process of updating, rebuilding and calibrating the MIKE SHE model will start, based on the latest data set. Prior to this, it is important to gather as much knowledge as possible on calibration methods and to define critical calibration parameters and areas within the model. In this project, an optimization of the numerical description and an initial calibration of the MIKE SHE model has been made, and an updated base case has been defined. Data from 5 surface water level monitoring stations, 4 surface water discharge monitoring stations and 32 groundwater level monitoring stations (SFM soil boreholes) has been used for model calibration and evaluation. The base case simulations generally show a good agreement between calculated and measured water levels and discharges, indicating that the total runoff from the area is well described by the model. Moreover, with two exceptions (SFM0012 and SFM0022) the base case results show very good agreement between calculated and measured groundwater head elevations for boreholes installed below lakes. The model also shows a reasonably good agreement between calculated and measured groundwater head elevations or depths to phreatic surfaces in many other points. The following major types of calculation-measurement differences can be noted: Differences in groundwater level amplitudes due to transpiration processes. Differences in absolute mean groundwater head, due to differences between borehole casing levels and the interpolated DEM. Differences in absolute mean head elevations, due to local errors in hydraulic conductivity values

  14. Sensitivity analysis and development of calibration methodology for near-surface hydrogeology model of Forsmark

    Energy Technology Data Exchange (ETDEWEB)

    Aneljung, Maria; Gustafsson, Lars-Goeran [DHI Water and Environment AB, Goeteborg (Sweden)

    2007-04-15

    The hydrological modelling system MIKE SHE has been used to describe near-surface groundwater flow, transport mechanisms and the contact between ground- and surface water at the Forsmark site. The surface water system at Forsmark is described with the 1D modelling tool MIKE 11, which is fully and dynamically integrated with MIKE SHE. In spring 2007, a new data freeze will be available and a process of updating, rebuilding and calibrating the MIKE SHE model will start, based on the latest data set. Prior to this, it is important to gather as much knowledge as possible on calibration methods and to define critical calibration parameters and areas within the model. In this project, an optimization of the numerical description and an initial calibration of the MIKE SHE model has been made, and an updated base case has been defined. Data from 5 surface water level monitoring stations, 4 surface water discharge monitoring stations and 32 groundwater level monitoring stations (SFM soil boreholes) has been used for model calibration and evaluation. The base case simulations generally show a good agreement between calculated and measured water levels and discharges, indicating that the total runoff from the area is well described by the model. Moreover, with two exceptions (SFM0012 and SFM0022) the base case results show very good agreement between calculated and measured groundwater head elevations for boreholes installed below lakes. The model also shows a reasonably good agreement between calculated and measured groundwater head elevations or depths to phreatic surfaces in many other points. The following major types of calculation-measurement differences can be noted: Differences in groundwater level amplitudes due to transpiration processes. Differences in absolute mean groundwater head, due to differences between borehole casing levels and the interpolated DEM. Differences in absolute mean head elevations, due to local errors in hydraulic conductivity values

  15. Infrared radiation parameterizations in numerical climate models

    Science.gov (United States)

    Chou, Ming-Dah; Kratz, David P.; Ridgway, William

    1991-01-01

    This study presents various approaches to parameterizing the broadband transmission functions for utilization in numerical climate models. One-parameter scaling is applied to approximate a nonhomogeneous path with an equivalent homogeneous path, and the diffuse transmittances are either interpolated from precomputed tables or fit by analytical functions. Two-parameter scaling is applied to parameterizing the carbon dioxide and ozone transmission functions in both the lower and middle atmosphere. Parameterizations are given for the nitrous oxide and methane diffuse transmission functions.

  16. THM large spatial-temporal model to simulate the past 2 Ma hydrogeological evolution of Paris Basin including natural tracer transport as part of site characterization for radwaste repository project Cigéo - France

    Science.gov (United States)

    Benabderrahmane, A., Sr.

    2017-12-01

    Hydrogeological site characterization for deep geological high level and intermediate level long lived radioactive waste repository cover a large time scale needed for safety analysis and calculation. Hydrogeological performance of a site relies also on the effects of geodynamic evolution as tectonic uplift, erosion/sedimentation and climate including glaciation on the groundwater flow and solute and heat transfer. Thermo-Hydro-Mechanical model of multilayered aquifer system of Paris Basin is developed to reproduce the present time flow and the natural tracer (Helium) concentration profiles based on the last 2 Ma of geodynamic evolution. Present time geological conceptual model consist of 27 layers at Paris Basin (Triassic-Tertiary) with refinement at project site scale (29 layers from Triassic to Portlandian). Target layers are the clay host formation of Callovo-Oxfrodian age (160 Ma) and the surrounding aquifer layers of Oxfordian and Dogger. Modelled processes are: groundwater flow, heat and solutes (natural tracers) transport, freezing and thawing of groundwater (expansion and retreat of permafrost), deformation of the multilayered aquifer system induced by differential tectonic uplift and the hydro-mechanical stress effect as caused by erosion of the outcropping layers. Numerical simulation considers a period from 2 Ma BP and up to the present. Transient boundary conditions are governed by geodynamic processes: (i) modification of the geometry of the basin and (ii) temperatures along the topography will change according to a series of 15 identical climate cycles with multiple permafrost (glaciation) periods. Numerical model contains 71 layers and 18 million cells. The solution procedure solves three coupled systems of equations, head, temperature and concentrations, by the use of a finite difference method, and by applying extensive parallel processing. The major modelling results related to the processes of importance for site characterization as hydraulic

  17. Salinity sources of Kefar Uriya wells in the Judea Group aquifer of Israel. Part 1—conceptual hydrogeological model

    Science.gov (United States)

    Avisar, D.; Rosenthal, E.; Flexer, A.; Shulman, H.; Ben-Avraham, Z.; Guttman, J.

    2003-01-01

    In the Yarkon-Taninim groundwater basin, the karstic Judea Group aquifer contains groundwater of high quality. However, in the western wells of the Kefar Uriya area located in the foothills of the Judea Mountains, brackish groundwater was locally encountered. The salinity of this water is caused presumably by two end members designated as the 'Hazerim' and 'Lakhish' water types. The Hazerim type represents surface water percolating through a highly fractured thin chalky limestone formation overlying the Judea Group aquifer. The salinity of the water derives conjointly from several sources such as leachates from rendzina and grumosols, dissolution of caliche crusts which contain evaporites and of rock debris from the surrounding formations. This surface water percolates downwards into the aquifer through a funnel- or chimney-like mechanism. This local salinization mechanism supercedes another regional process caused by the Lakhish waters. These are essentially diluted brines originating from deep formations in the western parts of the Coastal Plain. The study results show that salinization is not caused by the thick chalky beds of the Senonian Mt Scopus Group overlying the Judea Group aquifer, as traditionally considered but prevalently by aqueous leachates from soils and rock debris. The conceptual qualitative hydrogeological model of the salinization as demonstrated in this study, is supported by a quantitative hydrological model presented in another paper in this volume.

  18. Advanced Numerical Model for Irradiated Concrete

    Energy Technology Data Exchange (ETDEWEB)

    Giorla, Alain B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-03-01

    In this report, we establish a numerical model for concrete exposed to irradiation to address these three critical points. The model accounts for creep in the cement paste and its coupling with damage, temperature and relative humidity. The shift in failure mode with the loading rate is also properly represented. The numerical model for creep has been validated and calibrated against different experiments in the literature [Wittmann, 1970, Le Roy, 1995]. Results from a simplified model are shown to showcase the ability of numerical homogenization to simulate irradiation effects in concrete. In future works, the complete model will be applied to the analysis of the irradiation experiments of Elleuch et al. [1972] and Kelly et al. [1969]. This requires a careful examination of the experimental environmental conditions as in both cases certain critical information are missing, including the relative humidity history. A sensitivity analysis will be conducted to provide lower and upper bounds of the concrete expansion under irradiation, and check if the scatter in the simulated results matches the one found in experiments. The numerical and experimental results will be compared in terms of expansion and loss of mechanical stiffness and strength. Both effects should be captured accordingly by the model to validate it. Once the model has been validated on these two experiments, it can be applied to simulate concrete from nuclear power plants. To do so, the materials used in these concrete must be as well characterized as possible. The main parameters required are the mechanical properties of each constituent in the concrete (aggregates, cement paste), namely the elastic modulus, the creep properties, the tensile and compressive strength, the thermal expansion coefficient, and the drying shrinkage. These can be either measured experimentally, estimated from the initial composition in the case of cement paste, or back-calculated from mechanical tests on concrete. If some

  19. Study of the influence of hydrogeological conditions in the upper aquifer on radionuclide migration from a geological repository using a 2D groundwater flow model

    Energy Technology Data Exchange (ETDEWEB)

    Shestopalov, Vyacheslav; Bohuslavskyy, Alexander; Shybetskyi, Iurii [National Academy of Science of Ukaraine, Kyiv (Ukraine). Radioenvironmental Centre

    2015-07-01

    Results are presented of a case groundwater flow-transport modeling to predict the radionuclide migration from a deep geological repository (DGR) of radioactive waste. The influence of hydrogeological conditions in the upper aquifers of a storey water exchange system on the rate of contaminant migration from the DGR to its natural far-field groundwater discharges (a shallow well and a river) as a general DGR safety condition is considered.

  20. Numerical model simulation of atmospheric coolant plumes

    International Nuclear Information System (INIS)

    Gaillard, P.

    1980-01-01

    The effect of humid atmospheric coolants on the atmosphere is simulated by means of a three-dimensional numerical model. The atmosphere is defined by its natural vertical profiles of horizontal velocity, temperature, pressure and relative humidity. Effluent discharge is characterised by its vertical velocity and the temperature of air satured with water vapour. The subject of investigation is the area in the vicinity of the point of discharge, with due allowance for the wake effect of the tower and buildings and, where application, wind veer with altitude. The model equations express the conservation relationships for mometum, energy, total mass and water mass, for an incompressible fluid behaving in accordance with the Boussinesq assumptions. Condensation is represented by a simple thermodynamic model, and turbulent fluxes are simulated by introduction of turbulent viscosity and diffusivity data based on in-situ and experimental water model measurements. The three-dimensional problem expressed in terms of the primitive variables (u, v, w, p) is governed by an elliptic equation system which is solved numerically by application of an explicit time-marching algorithm in order to predict the steady-flow velocity distribution, temperature, water vapour concentration and the liquid-water concentration defining the visible plume. Windstill conditions are simulated by a program processing the elliptic equations in an axisymmetrical revolution coordinate system. The calculated visible plumes are compared with plumes observed on site with a view to validate the models [fr

  1. Numerical modelling of methanol liquid pool fires

    Science.gov (United States)

    Prasad, Kuldeep; Li, Chiping; Kailasanath, K.; Ndubizu, Chuka; Ananth, Ramagopal; Tatem, P. A.

    1999-12-01

    The focus of this paper is on numerical modelling of methanol liquid pool fires. A mathematical model is first developed to describe the evaporation and burning of a two-dimensional or axisymmetric pool containing pure liquid methanol. Then, the complete set of unsteady, compressible Navier-Stokes equations for reactive flows are solved in the gas phase to describe the convection of the fuel gases away from the pool surface, diffusion of the gases into the surrounding air and the oxidation of the fuel into product species. Heat transfer into the liquid pool and the metal container through conduction, convection and radiation are modelled by solving a modified form of the energy equation. Clausius-Clapeyron relationships are invoked to model the evaporation rate of a two-dimensional pool of pure liquid methanol. The governing equations along with appropriate boundary and interface conditions are solved using the flux-corrected transport algorithm. Numerical results exhibit a flame structure that compares well with experimental observations. Temperature profiles and burning rates were found to compare favourably with experimental data from single- and three-compartment laboratory burners. The model predicts a puffing frequency of approximately 12 Hz for a 1 cm diameter methanol pool in the absence of any air co-flow. It is also observed that increasing the air co-flow velocity helps in stabilizing the diffusion flame, by pushing the vortical structures away from the flame region.

  2. A Numerical Model for Trickle Bed Reactors

    Science.gov (United States)

    Propp, Richard M.; Colella, Phillip; Crutchfield, William Y.; Day, Marcus S.

    2000-12-01

    Trickle bed reactors are governed by equations of flow in porous media such as Darcy's law and the conservation of mass. Our numerical method for solving these equations is based on a total-velocity splitting, sequential formulation which leads to an implicit pressure equation and a semi-implicit mass conservation equation. We use high-resolution finite-difference methods to discretize these equations. Our solution scheme extends previous work in modeling porous media flows in two ways. First, we incorporate physical effects due to capillary pressure, a nonlinear inlet boundary condition, spatial porosity variations, and inertial effects on phase mobilities. In particular, capillary forces introduce a parabolic component into the recast evolution equation, and the inertial effects give rise to hyperbolic nonconvexity. Second, we introduce a modification of the slope-limiting algorithm to prevent our numerical method from producing spurious shocks. We present a numerical algorithm for accommodating these difficulties, show the algorithm is second-order accurate, and demonstrate its performance on a number of simplified problems relevant to trickle bed reactor modeling.

  3. Numerical modelling of swirling diffusive flames

    Directory of Open Access Journals (Sweden)

    Parra-Santos Teresa

    2016-01-01

    Full Text Available Computational Fluid Dynamics has been used to study the mixing and combustion of two confined jets whose setup and operating conditions are those of the benchmark of Roback and Johnson. Numerical model solves 3D transient Navier Stokes for turbulent and reactive flows. Averaged velocity profiles using RNG swirl dominated k-epsilon model have been validated with experimental measurements from other sources for the non reactive case. The combustion model is Probability Density Function. Bearing in mind the annular jet has swirl number over 0.5, a vortex breakdown appears in the axis of the burner. Besides, the sudden expansion with a ratio of 2 in diameter between nozzle exits and the test chamber produces the boundary layer separation with the corresponding torus shape recirculation. Contrasting the mixing and combustion models, the last one produces the reduction of the vortex breakdown.

  4. Hydrogeology of Gypsum formations

    Directory of Open Access Journals (Sweden)

    Klimchouk A.

    1996-01-01

    Full Text Available Detailed explanation of hydrogeological characteristics of gypsum aquifers is given in various situations: deep-seated karst-confined conditions, subjacent, entrenched and denuded karst types-semi-confined, phreatic and vadose conditions. The hydrogeological evolution of barren exposed gypsum karst and flow velocities in gypsum karst aquifers is also discussed.

  5. Aerosol numerical modelling at local scale

    International Nuclear Information System (INIS)

    Albriet, Bastien

    2007-01-01

    At local scale and in urban areas, an important part of particulate pollution is due to traffic. It contributes largely to the high number concentrations observed. Two aerosol sources are mainly linked to traffic. Primary emission of soot particles and secondary nanoparticle formation by nucleation. The emissions and mechanisms leading to the formation of such bimodal distribution are still badly understood nowadays. In this thesis, we try to provide an answer to this problematic by numerical modelling. The Modal Aerosol Model MAM is used, coupled with two 3D-codes: a CFD (Mercure Saturne) and a CTM (Polair3D). A sensitivity analysis is performed, at the border of a road but also in the first meters of an exhaust plume, to identify the role of each process involved and the sensitivity of different parameters used in the modelling. (author) [fr

  6. Posttraumatic Orbital Emphysema: A Numerical Model

    Directory of Open Access Journals (Sweden)

    Andrzej Skorek

    2014-01-01

    Full Text Available Orbital emphysema is a common symptom accompanying orbital fracture. The pathomechanism is still not recognized and the usually assumed cause, elevated pressure in the upper airways connected with sneezing or coughing, does not always contribute to the occurrence of this type of fracture. Observations based on the finite model (simulating blowout type fracture of the deformations of the inferior orbital wall after a strike in its lower rim. Authors created a computer numeric model of the orbit with specified features—thickness and resilience modulus. During simulation an evenly spread 14400 N force was applied to the nodular points in the inferior rim (the maximal value not causing cracking of the outer rim, but only ruptures in the inferior wall. The observation was made from 1·10-3 to 1·10-2 second after a strike. Right after a strike dislocations of the inferior orbital wall toward the maxillary sinus were observed. Afterwards a retrograde wave of the dislocation of the inferior wall toward the orbit was noticed. Overall dislocation amplitude reached about 6 mm. Based on a numeric model of the orbit submitted to a strike in the inferior wall an existence of a retrograde shock wave causing orbital emphysema has been found.

  7. Numerical modeling of atmospheric washout processes

    International Nuclear Information System (INIS)

    Bayer, D.; Beheng, K.D.; Herbert, F.

    1987-01-01

    For the washout of particles from the atmosphere by clouds and rain one has to distinguish between processes which work in the first phase of cloud development, when condensation nuclei build up in saturated air (Nucleation Aerosol Scavenging, NAS) and those processes which work at the following cloud development. In the second case particles are taken off by cloud droplets or by falling rain drops via collision (Collision Aerosol Scavenging, CAS). The physics of both processes is described. For the CAS process a numerical model is presented. The report contains a documentation of the mathematical equations and the computer programs (FORTRAN). (KW) [de

  8. Hydrogeological framework and geometry modeling via joint gravity and borehole parameters, the Nadhour-Sisseb-El Alem basin (central-eastern Tunisia)

    Science.gov (United States)

    Souei, Ali; Atawa, Mohamed; Zouaghi, Taher

    2018-03-01

    The Nadhour-Sisseb-El Alem basin, in the central-eastern part of Tunisia, is characterized by the scarcity of surface and subsurface water resources. Although the aquifer systems of this basin are not well understood, the scarce water resources are subject to a high rate of exploitation leading to a significant drop in the level of the water table. This work presents correlation of gravity data with hydrogeological data in order to improve the knowledge of the deep structures and aquifer systems. Various geophysical filtering techniques (e.g., residual anomaly, upward continuation, horizontal gradient, and Euler deconvolution) applied to the complete Bouguer anomaly, deduce the deep structures and geometry of the basin and highlight gravity lineaments that correspond to the tectonic features. The structural framework of the Nadhour-Sisseb-El Alem hydrogeological basin shows N-S to NNE-SSW and E-W oriented structures that should be related to tectonic deformations. In addition to the faults, previously recognized, new lineaments are highlighted by the present work. They correspond to NE-, NW-, E- and N- trending faults that have controlled structuring and geometry of the basin. 2D gravity forward modeling, based on the interpretation of geophysical, geological and hydrogeological data, led to a better understanding of the basin geometry and spatial distribution of the Campanian-Maastrichtian and Cenozoic potential aquifers. Three hydrogeological sub-basins identified include the Nadhour sub-basin in the north, the El Alem sub-Basin in the South and the Etrabelsia sub-Basin in the East. These sub-basins are marked by a thickening of deposits, are separated by the Sisseb-Fadeloun raised structure of Neogene and Quaternary thinned series. The results allow the determination of limit conditions for the basin hydrodynamic evolution and explain some anomalies on the quantity and quality of the groundwater. They provide a management guide for water resources prospection in

  9. NUMERICAL MODEL APPLICATION IN ROWING SIMULATOR DESIGN

    Directory of Open Access Journals (Sweden)

    Petr Chmátal

    2016-04-01

    Full Text Available The aim of the research was to carry out a hydraulic design of rowing/sculling and paddling simulator. Nowadays there are two main approaches in the simulator design. The first one includes a static water with no artificial movement and counts on specially cut oars to provide the same resistance in the water. The second approach, on the other hand uses pumps or similar devices to force the water to circulate but both of the designs share many problems. Such problems are affecting already built facilities and can be summarized as unrealistic feeling, unwanted turbulent flow and bad velocity profile. Therefore, the goal was to design a new rowing simulator that would provide nature-like conditions for the racers and provide an unmatched experience. In order to accomplish this challenge, it was decided to use in-depth numerical modeling to solve the hydraulic problems. The general measures for the design were taken in accordance with space availability of the simulator ́s housing. The entire research was coordinated with other stages of the construction using BIM. The detailed geometry was designed using a numerical model in Ansys Fluent and parametric auto-optimization tools which led to minimum negative hydraulic phenomena and decreased investment and operational costs due to the decreased hydraulic losses in the system.

  10. Hydrogeological characterization of the Stripa site

    International Nuclear Information System (INIS)

    Gale, J.; Macleod, R.; Welhan, J.; Cole, C.; Vail, L.

    1987-06-01

    This study was initiated in January, 1986, to determine a) if the permeability of the rock mass in the immediate mine area was anisotropic, b) the effective and total fracture porosity distributions based on field and laboratory data and c) the three-dimensional configuration of the groundwater flow system at Stripa in order to properly interpret the hydrogeological, geochemical and isotopic data. The total and flow porosities of single fractures from Stripa were determined in the laboratory using a resin impregnation technique. The three-dimensional numerical model gave mine inflows that were consistent with the measured mine inflows with perturbations extending to at least 3,000 m of depth. (orig./DG)

  11. Characterization of hydrogeologic units using matrix properties, Yucca Mountain, Nevada

    Science.gov (United States)

    Flint, L.E.

    1998-01-01

    Determination of the suitability of Yucca Mountain, in southern Nevada, as a geologic repository for high-level radioactive waste requires the use of numerical flow and transport models. Input for these models includes parameters that describe hydrologic properties and the initial and boundary conditions for all rock materials within the unsaturated zone, as well as some of the upper rocks in the saturated zone. There are 30 hydrogeologic units in the unsaturated zone, and each unit is defined by limited ranges where a discrete volume of rock contains similar hydrogeologic properties. These hydrogeologic units can be easily located in space by using three-dimensional lithostratigraphic models based on relation- ships of the properties with the lithostratigraphy. Physical properties of bulk density, porosity, and particle density; flow properties of saturated hydraulic conductivity and moisture-retention characteristics; and the state variables (variables describing the current state of field conditions) of saturation and water potential were determined for each unit. Units were defined using (1) a data base developed from 4,892 rock samples collected from the coring of 23 shallow and 8 deep boreholes, (2) described lithostratigraphic boundaries and corresponding relations to porosity, (3) recognition of transition zones with pronounced changes in properties over short vertical distances, (4) characterization of the influence of mineral alteration on hydrologic properties such as permeability and moisture-retention characteristics, and (5) a statistical analysis to evaluate where boundaries should be adjusted to minimize the variance within layers. This study describes the correlation of hydrologic properties to porosity, a property that is well related to the lithostratigraphy and depositional and cooling history of the volcanic deposits and can, therefore, be modeled to be distributed laterally. Parameters of the hydrogeologic units developed in this study and the

  12. Numerical modeling of materials under extreme conditions

    CERN Document Server

    Brown, Eric

    2014-01-01

    The book presents twelve state of the art contributions in the field of numerical modeling of materials subjected to large strain, high strain rates, large pressure and high stress triaxialities, organized into two sections. The first part is focused on high strain rate-high pressures such as those occurring in impact dynamics and shock compression related phenomena, dealing with material response identification, advanced modeling incorporating microstructure and damage, stress waves propagation in solids and structures response under impact. The latter part is focused on large strain-low strain rates applications such as those occurring in technological material processing, dealing with microstructure and texture evolution, material response at elevated temperatures, structural behavior under large strain and multi axial state of stress.

  13. Partial Differential Equations Modeling and Numerical Simulation

    CERN Document Server

    Glowinski, Roland

    2008-01-01

    This book is dedicated to Olivier Pironneau. For more than 250 years partial differential equations have been clearly the most important tool available to mankind in order to understand a large variety of phenomena, natural at first and then those originating from human activity and technological development. Mechanics, physics and their engineering applications were the first to benefit from the impact of partial differential equations on modeling and design, but a little less than a century ago the Schrödinger equation was the key opening the door to the application of partial differential equations to quantum chemistry, for small atomic and molecular systems at first, but then for systems of fast growing complexity. Mathematical modeling methods based on partial differential equations form an important part of contemporary science and are widely used in engineering and scientific applications. In this book several experts in this field present their latest results and discuss trends in the numerical analy...

  14. A delta-rule model of numerical and non-numerical order processing.

    Science.gov (United States)

    Verguts, Tom; Van Opstal, Filip

    2014-06-01

    Numerical and non-numerical order processing share empirical characteristics (distance effect and semantic congruity), but there are also important differences (in size effect and end effect). At the same time, models and theories of numerical and non-numerical order processing developed largely separately. Currently, we combine insights from 2 earlier models to integrate them in a common framework. We argue that the same learning principle underlies numerical and non-numerical orders, but that environmental features determine the empirical differences. Implications for current theories on order processing are pointed out. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  15. Adaptive Numerical Algorithms in Space Weather Modeling

    Science.gov (United States)

    Toth, Gabor; vanderHolst, Bart; Sokolov, Igor V.; DeZeeuw, Darren; Gombosi, Tamas I.; Fang, Fang; Manchester, Ward B.; Meng, Xing; Nakib, Dalal; Powell, Kenneth G.; hide

    2010-01-01

    Space weather describes the various processes in the Sun-Earth system that present danger to human health and technology. The goal of space weather forecasting is to provide an opportunity to mitigate these negative effects. Physics-based space weather modeling is characterized by disparate temporal and spatial scales as well as by different physics in different domains. A multi-physics system can be modeled by a software framework comprising of several components. Each component corresponds to a physics domain, and each component is represented by one or more numerical models. The publicly available Space Weather Modeling Framework (SWMF) can execute and couple together several components distributed over a parallel machine in a flexible and efficient manner. The framework also allows resolving disparate spatial and temporal scales with independent spatial and temporal discretizations in the various models. Several of the computationally most expensive domains of the framework are modeled by the Block-Adaptive Tree Solar wind Roe Upwind Scheme (BATS-R-US) code that can solve various forms of the magnetohydrodynamics (MHD) equations, including Hall, semi-relativistic, multi-species and multi-fluid MHD, anisotropic pressure, radiative transport and heat conduction. Modeling disparate scales within BATS-R-US is achieved by a block-adaptive mesh both in Cartesian and generalized coordinates. Most recently we have created a new core for BATS-R-US: the Block-Adaptive Tree Library (BATL) that provides a general toolkit for creating, load balancing and message passing in a 1, 2 or 3 dimensional block-adaptive grid. We describe the algorithms of BATL and demonstrate its efficiency and scaling properties for various problems. BATS-R-US uses several time-integration schemes to address multiple time-scales: explicit time stepping with fixed or local time steps, partially steady-state evolution, point-implicit, semi-implicit, explicit/implicit, and fully implicit numerical

  16. Multiple-point statistical simulation for hydrogeological models: 3-D training image development and conditioning strategies

    Directory of Open Access Journals (Sweden)

    A.-S. Høyer

    2017-12-01

    Full Text Available Most studies on the application of geostatistical simulations based on multiple-point statistics (MPS to hydrogeological modelling focus on relatively fine-scale models and concentrate on the estimation of facies-level structural uncertainty. Much less attention is paid to the use of input data and optimal construction of training images. For instance, even though the training image should capture a set of spatial geological characteristics to guide the simulations, the majority of the research still relies on 2-D or quasi-3-D training images. In the present study, we demonstrate a novel strategy for 3-D MPS modelling characterized by (i realistic 3-D training images and (ii an effective workflow for incorporating a diverse group of geological and geophysical data sets. The study covers an area of 2810 km2 in the southern part of Denmark. MPS simulations are performed on a subset of the geological succession (the lower to middle Miocene sediments which is characterized by relatively uniform structures and dominated by sand and clay. The simulated domain is large and each of the geostatistical realizations contains approximately 45 million voxels with size 100 m  ×  100 m  ×  5 m. Data used for the modelling include water well logs, high-resolution seismic data, and a previously published 3-D geological model. We apply a series of different strategies for the simulations based on data quality, and develop a novel method to effectively create observed spatial trends. The training image is constructed as a relatively small 3-D voxel model covering an area of 90 km2. We use an iterative training image development strategy and find that even slight modifications in the training image create significant changes in simulations. Thus, this study shows how to include both the geological environment and the type and quality of input information in order to achieve optimal results from MPS modelling. We present a practical

  17. A conceptual hydrogeological model of ophiolitic aquifers (serpentinised peridotite): The test example of Mt. Prinzera (Northern Italy)

    NARCIS (Netherlands)

    Segadelli, Stefano; Vescovi, Paolo; Ogata, Kei; Chelli, Alessandro; Zanini, Andrea; Boschetti, Tiziano; Petrella, Emma; Toscani, Lorenzo; Gargini, Alessandro; Celico, Fulvio

    2017-01-01

    © 2016 John Wiley & Sons, Ltd.The main aim of this study is the experimental analysis of the hydrogeological behaviour of the Mt. Prinzera ultramafic massif in the northern Apennines, Italy. The analysed multidisciplinary database has been acquired through (a) geologic and structural survey; (b)

  18. Hydrogeological modelling of the Atlantis aquifer for management support to the Atlantis water supply scheme

    CSIR Research Space (South Africa)

    Jovanovic, Nebo

    2017-01-01

    Full Text Available model MODFLOW for groundwater flow and contaminant transport was used in support of the management of the AWSS. The aims were: (i) to calibrate the MODFLOW model for the MAR site at Atlantis; (ii) to run realistic scenarios that cannot be replicated...

  19. Numerical modelling of ion transport in flames

    KAUST Repository

    Han, Jie

    2015-10-20

    This paper presents a modelling framework to compute the diffusivity and mobility of ions in flames. The (n, 6, 4) interaction potential is adopted to model collisions between neutral and charged species. All required parameters in the potential are related to the polarizability of the species pair via semi-empirical formulas, which are derived using the most recently published data or best estimates. The resulting framework permits computation of the transport coefficients of any ion found in a hydrocarbon flame. The accuracy of the proposed method is evaluated by comparing its predictions with experimental data on the mobility of selected ions in single-component neutral gases. Based on this analysis, the value of a model constant available in the literature is modified in order to improve the model\\'s predictions. The newly determined ion transport coefficients are used as part of a previously developed numerical approach to compute the distribution of charged species in a freely propagating premixed lean CH4/O2 flame. Since a significant scatter of polarizability data exists in the literature, the effects of changes in polarizability on ion transport properties and the spatial distribution of ions in flames are explored. Our analysis shows that changes in polarizability propagate with decreasing effect from binary transport coefficients to species number densities. We conclude that the chosen polarizability value has a limited effect on the ion distribution in freely propagating flames. We expect that the modelling framework proposed here will benefit future efforts in modelling the effect of external voltages on flames. Supplemental data for this article can be accessed at http://dx.doi.org/10.1080/13647830.2015.1090018. © 2015 Taylor & Francis.

  20. Hydrogeology of Virginia

    Science.gov (United States)

    Nelms, David L.; Harlow, George; Bruce, T. Scott; Bailey, Christopher M.; Sherwood, W. Cullen; Eaton, L. Scott; Powars, David S.

    2016-01-01

    The hydrogeology of Virginia documented herein is in two parts. Part 1 consists of an overview and description of the hydrogeology within each regional aquifer system in the Commonwealth. Part 2 includes discussions of hydrogeologic research topics of current relevance including: 1. the Chesapeake Bay impact structure, 2. subsidence/compaction in the Coastal Plain, 3. groundwater age and aquifer susceptibility, 4. the occurrence of groundwater at depth in fractured-rock and karst terrains, and 5. hydrologic response of wells to earthquakes around the world.

  1. Modeling and numerical simulations of the influenced Sznajd model

    Science.gov (United States)

    Karan, Farshad Salimi Naneh; Srinivasan, Aravinda Ramakrishnan; Chakraborty, Subhadeep

    2017-08-01

    This paper investigates the effects of independent nonconformists or influencers on the behavioral dynamic of a population of agents interacting with each other based on the Sznajd model. The system is modeled on a complete graph using the master equation. The acquired equation has been numerically solved. Accuracy of the mathematical model and its corresponding assumptions have been validated by numerical simulations. Regions of initial magnetization have been found from where the system converges to one of two unique steady-state PDFs, depending on the distribution of influencers. The scaling property and entropy of the stationary system in presence of varying level of influence have been presented and discussed.

  2. Mathematical models and numerical simulation in electromagnetism

    CERN Document Server

    Bermúdez, Alfredo; Salgado, Pilar

    2014-01-01

    The book represents a basic support for a master course in electromagnetism oriented to numerical simulation. The main goal of the book is that the reader knows the boundary-value problems of partial differential equations that should be solved in order to perform computer simulation of electromagnetic processes. Moreover it includes a part devoted to electric circuit theory  based on ordinary differential equations. The book is mainly oriented to electric engineering applications, going from the general to the specific, namely, from the full Maxwell’s equations to the particular cases of electrostatics, direct current, magnetostatics and eddy currents models. Apart from standard exercises related to analytical calculus, the book includes some others oriented to real-life applications solved with MaxFEM free simulation software.

  3. Numerical modeling capabilities to predict repository performance

    International Nuclear Information System (INIS)

    1979-09-01

    This report presents a summary of current numerical modeling capabilities that are applicable to the design and performance evaluation of underground repositories for the storage of nuclear waste. The report includes codes that are available in-house, within Golder Associates and Lawrence Livermore Laboratories; as well as those that are generally available within the industry and universities. The first listing of programs are in-house codes in the subject areas of hydrology, solute transport, thermal and mechanical stress analysis, and structural geology. The second listing of programs are divided by subject into the following categories: site selection, structural geology, mine structural design, mine ventilation, hydrology, and mine design/construction/operation. These programs are not specifically designed for use in the design and evaluation of an underground repository for nuclear waste; but several or most of them may be so used

  4. Ocean wave prediction using numerical and neural network models

    Digital Repository Service at National Institute of Oceanography (India)

    Mandal, S.; Prabaharan, N.

    This paper presents an overview of the development of the numerical wave prediction models and recently used neural networks for ocean wave hindcasting and forecasting. The numerical wave models express the physical concepts of the phenomena...

  5. Numerical modeling of bubble dynamics in magmas

    Science.gov (United States)

    Huber, Christian; Su, Yanqing; Parmigiani, Andrea

    2014-05-01

    Understanding the complex non-linear physics that governs volcanic eruptions is contingent on our ability to characterize the dynamics of bubbles and its effect on the ascending magma. The exsolution and migration of bubbles has also a great impact on the heat and mass transport in and out of magma bodies stored at shallow depths in the crust. Multiphase systems like magmas are by definition heterogeneous at small scales. Although mixture theory or homogenization methods are convenient to represent multiphase systems as a homogeneous equivalent media, these approaches do not inform us on possible feedbacks at the pore-scale and can be significantly misleading. In this presentation, we discuss the development and application of bubble-scale multiphase flow modeling to address the following questions : How do bubbles impact heat and mass transport in magma chambers ? How efficient are chemical exchanges between the melt and bubbles during magma decompression? What is the role of hydrodynamic interactions on the deformation of bubbles while the magma is sheared? Addressing these questions requires powerful numerical methods that accurately model the balance between viscous, capillary and pressure stresses. We discuss how these bubble-scale models can provide important constraints on the dynamics of magmas stored at shallow depth or ascending to the surface during an eruption.

  6. Numerical modeling of polar mesocyclones generation mechanisms

    Science.gov (United States)

    Sergeev, Dennis; Stepanenko, Victor

    2013-04-01

    parameters, lateral boundary conditions are varied in the typically observed range. The approach is fully nonlinear: we use a three-dimensional non-hydrostatic mesoscale model NH3D_MPI [1] coupled with one-dimensional water body model LAKE. A key method used in the present study is the analysis of eddy kinetic and available potential energy budgets. References 1. Mikushin, D.N., and Stepanenko, V.M., The implementation of regional atmospheric model numerical algorithms for CBEA-based clusters. Lecture Notes in Computer Science, Parallel Processing and Applied Mathematics, 2010, vol. 6067, p. 525-534. 2. Rasmussen, E., and Turner, J. (eds), Polar Lows: Mesoscale Weather Systems in the Polar Regions. Cambridge: Cambridge University Press, 2003, 612 pp. 3. Yanase, W., and Niino, H., Dependence of Polar Low Development on Baroclinicity and Physical Processes: An Idealized High-Resolution Experiment, J. Atmos. Sci., 2006, vol. 64, p. 3044-3067.

  7. Numerical Modelling of Flow and Settling in Secondary Settling Tanks

    DEFF Research Database (Denmark)

    Dahl, Claus Poulsen

    This thesis discusses the development of a numerical model for the simulation of secondary settling tanks. In the first part, the status on the development of numerical models for settling tanks and a discussion of the current design practice are presented. A study of the existing numerical models...... and design practice proved a demand for further development to include numerical models in the design of settling tanks, thus improving the future settling tanks....

  8. HYDROGEOLOGIC CASE STUDIES

    Science.gov (United States)

    Hydrogeology is the foundation of subsurface site characterization for evaluations of monitored natural attenuation (MNA). Three case studies are presented. Examples of the potentially detrimental effects of drilling additives on ground-water samples from monitoring wells are d...

  9. Hydrogeological flux scenarios at Forsmark. Generic numerical flow simulations and compilation of climatic information for use in the safety analysis SFR1 SAR-08

    International Nuclear Information System (INIS)

    Vidstrand, Patrik; Naeslund, Jens-Ove; Hartikainen, Juha; Svensson, Urban

    2007-11-01

    In the earlier modelling for SFR-SAFE it was concluded that the groundwater flow would increase with time along with the shoreline displacement. Even though the numerical results are different the same conclusion is drawn after this study. General conclusions from the present study are that: The upper boundary conditions have a significant impact on the groundwater flow in the geosphere. The characteristic of the surface in regards of being a recharge or discharge area affects the results. In general, a discharge area will experience an increase in groundwater flow under changed conditions. The presence of caging fracture zones affects the results, and, for the tested un-frozen SFR situation, the resulting effect is an increase in groundwater flow. Specific conclusions regarding the relative change of groundwater flow due to different surface conditions are that: The permafrost scenarios, along with the development from sporadic permafrost to continuous permafrost, yield increased groundwater flows in unfrozen parts of the domain. The increase is one order of magnitude or less. In the permafrost, the flow is negligible. The ice sheet scenarios yield situations with significantly increased groundwater flow. The results indicate an increase by two to three orders of magnitude. These increased values, however, apply only for short duration intervals. It is possible that such intervals may be only a couple of years. In the selected climate Base variant, repeating the conditions for the last glacial cycle, permafrost conditions occur after 8,000 years. In the climate variant affected by increased greenhouse warming, permafrost conditions do not occur until after more than 50,000 years. In the chosen climate variants, ice sheets reach the Forsmark area and cause significantly increased groundwater flow, after ∼60,000 years or more

  10. Hydrogeological flux scenarios at Forsmark. Generic numerical flow simulations and compilation of climatic information for use in the safety analysis SFR1 SAR-08

    Energy Technology Data Exchange (ETDEWEB)

    Vidstrand, Patrik (Bergab, Goeteborg (SE)); Naeslund, Jens-Ove (Swedish Nuclear Fuel and Waste Management Co., Stockholm (SE)); Hartikainen, Juha (Helsinki Univ. of Technology, Helsinki (FI)); Svensson, Urban (CFE AB, Karlskrona (SE))

    2007-11-15

    In the earlier modelling for SFR-SAFE it was concluded that the groundwater flow would increase with time along with the shoreline displacement. Even though the numerical results are different the same conclusion is drawn after this study. General conclusions from the present study are that: The upper boundary conditions have a significant impact on the groundwater flow in the geosphere. The characteristic of the surface in regards of being a recharge or discharge area affects the results. In general, a discharge area will experience an increase in groundwater flow under changed conditions. The presence of caging fracture zones affects the results, and, for the tested un-frozen SFR situation, the resulting effect is an increase in groundwater flow. Specific conclusions regarding the relative change of groundwater flow due to different surface conditions are that: The permafrost scenarios, along with the development from sporadic permafrost to continuous permafrost, yield increased groundwater flows in unfrozen parts of the domain. The increase is one order of magnitude or less. In the permafrost, the flow is negligible. The ice sheet scenarios yield situations with significantly increased groundwater flow. The results indicate an increase by two to three orders of magnitude. These increased values, however, apply only for short duration intervals. It is possible that such intervals may be only a couple of years. In the selected climate Base variant, repeating the conditions for the last glacial cycle, permafrost conditions occur after 8,000 years. In the climate variant affected by increased greenhouse warming, permafrost conditions do not occur until after more than 50,000 years. In the chosen climate variants, ice sheets reach the Forsmark area and cause significantly increased groundwater flow, after approx60,000 years or more

  11. Hydrogeological assessment based on ground water flow modeling around Atbara town

    International Nuclear Information System (INIS)

    Ahmed, S. H. M.

    2010-10-01

    Study area lies in the River Nile state North Central of Sudan between latitudes 17 o 34 - 18 o 00 N and longitudes 33 o 55 - 34 o 43 E. The geological settings of the study area are composed of pre-Cambrian Basement Complex, upper Cretaceous Nubian sandstone formation, Oligocene Hudi Chert, and quaternary superficial deposits in ascending order. Generally there are two main aquifers: shallow or upper aquifer in the alluvial deposits (5 - 37 m thick) and deep or lower aquifer in cretaceous Nubian sand stone (17 - 60 m). The upper aquifer is semi confined, whereas, the lower aquifer is almost confined except in the area around Atbara Town. Hydraulic conductivities of the aquifer varies between 1.89 x 10 -1 to 8.95 x 10 -1 m/min. Most of the water quality in the study area is suitable for domestic, agriculture, and industrial used with the exception of small pockets at Atbara town and some village in West of study area where salinity and contaminations were detected. Generally most of water quality in the study area is fit for human consumption. The ground water flow model of the study area was constricted using 40 column, 50 rows and 3 layers, forming 6000 cells covering the model domain. The model was calibrated using 3D Finite difference visual MODFLOW. The model calibration criteria such as mean absolute error (MAE), root mean square error (RMS) and mass balance error of water into and of out of the system were adjusted to less 1.3, 1.6 m, and 2.5% respectively. The contour maps of the simulated heads produced by visual MODFLOW show fair similarity with the contour map drawn using initial heads which confirm the reliability of Visual MODFLOW application and acceptable model calibration for the problem. As the result of model prediction, the calibration seemed to be more acceptable with average (RMS) of 2.5 m and average absolute mean error (AM) of 1.38 m and average normalized root mean square (NRMS) of (2.02%). Prediction results reflect the increasing of

  12. Joint inversion of seismic refraction and resistivity data using layered models - applications to hydrogeology

    Science.gov (United States)

    Juhojuntti, N. G.; Kamm, J.

    2010-12-01

    We present a layered-model approach to joint inversion of shallow seismic refraction and resistivity (DC) data, which we believe is a seldom tested method of addressing the problem. This method has been developed as we believe that for shallow sedimentary environments (roughly fairly simple 2D geometries, mainly for checking the validity of the calculations. The inversion generally converges towards the correct solution, although there could be stability problems if the starting model is too erroneous. We have also applied the code to field data from seismic refraction and multi-electrode resistivity measurements at typical sand-gravel groundwater reservoirs. The tests are promising, as the calculated depths agree fairly well with information from drilling and the velocity and resistivity values appear reasonable. Current work includes better regularization of the inversion as well as defining individual weight factors for the different datasets, as the present algorithm tends to constrain the depths mainly by using the seismic data. More complex synthetic examples will also be tested, including models addressing the seismic hidden-layer problem.

  13. Numerical modeling of the autumnal thermal bar

    Science.gov (United States)

    Tsydenov, Bair O.

    2018-03-01

    The autumnal riverine thermal bar of Kamloops Lake has been simulated using atmospheric data from December 1, 2015, to January 4, 2016. The nonhydrostatic 2.5D mathematical model developed takes into account the diurnal variability of the heat fluxes and wind on the lake surface. The average values for shortwave and longwave radiation and latent and sensible heat fluxes were 19.7 W/m2, - 95.9 W/m2, - 11.8 W/m2, and - 32.0 W/m2 respectively. Analysis of the wind regime data showed prevailing easterly winds and maximum speed of 11 m/s on the 8th and 19th days. Numerical experiments with different boundary conditions at the lake surface were conducted to evaluate effects of variable heat flux and wind stress. The results of modeling demonstrated that the variable heat flux affects the process of thermal bar evolution, especially during the lengthy night cooling. However, the wind had the greatest impact on the behavior of the autumnal thermal bar: The easterly winds contributed to an earlier appearance of the thermal bar, but the strong winds generating the intensive circulations (the velocity of the upper lake flow increased to 6 cm/s) may destroy the thermal bar front.

  14. A numerical model of aerosol scavenging

    International Nuclear Information System (INIS)

    Bradley, M.M.; Molenkamp, C.R.

    1991-10-01

    Using a three-dimensional numerical cloud/smoke-plume model, we have simulated the burning of a large, mid-latitude city following a nuclear exchange. The model includes 18 dynamic and microphysical equations that predict the fire-driven airflow, cloud processes, and smoke-cloud interactions. In the simulation, the intense heating from the burning city produces a firestorm with updraft velocities exceeding 60 m/s. Within 15 minutes of ignition, the smoke plume penetrates the tropopause. The updraft triggers a cumulonimbus cloud that produces significant quantities of ice, snow, and hail. These solid hydrometeors, as well as cloud droplets and rain, interact with the smoke particles from the fire. At the end of the one-hour simulation, over 20% of the smoke is in slowly falling snowflakes. If the snow reaches the ground before the flakes completely sublimate (or melt and then evaporate), then only approximately 50% of the smoke will survive the scavenging processes and remain in the atmosphere to affect the global climate

  15. Numerical Modelling of Seismic Slope Stability

    Science.gov (United States)

    Bourdeau, Céline; Havenith, Hans-Balder; Fleurisson, Jean-Alain; Grandjean, Gilles

    Earthquake ground-motions recorded worldwide have shown that many morphological and geological structures (topography, sedimentary basin) are prone to amplify the seismic shaking (San Fernando, 1971 [Davis and West 1973] Irpinia, 1980 [Del Pezzo et al. 1983]). This phenomenon, called site effects, was again recently observed in El Salvador when, on the 13th of January 2001, the country was struck by a M = 7.6 earthquake. Indeed, while horizontal accelerations on a rock site at Berlin, 80 km from the epicentre, did not exceed 0.23 g, they reached 0.6 g at Armenia, 110 km from the epicentre. Armenia is located on a small hill underlaid by a few meters thick pyroclastic deposits. Both the local topography and the presence of surface layers are likely to have caused the observed amplification effects, which are supposed to have contributed to the triggering of some of the hundreds of landslides related to this seismic event (Murphy et al. 2002). In order to better characterize the way site effects may influence the triggering of landslides along slopes, 2D numerical elastic and elasto-plastic models were developed. Various geometrical, geological and seismic conditions were analysed and the dynamic behaviour of the slope under these con- ditions was studied in terms of creation and location of a sliding surface. Preliminary results suggest that the size of modelled slope failures is dependent on site effects.

  16. Effects on surface hydrology and near-surface hydrogeology of an open repository in Laxemar Results of modelling with MIKE SHE

    International Nuclear Information System (INIS)

    Maartensson, Erik; Gustafsson, Lars-Goeran; Bosson, Emma

    2009-10-01

    This report presents the methodology and the results from the modelling of an open repository for spent nuclear fuel in Laxemar. Specifically, the present work analyses the hydrological effects of the planned repository during the construction and operational phases when it is open, i.e. air-filled, and hence may cause a disturbance of the hydrological conditions in the surroundings. The numerical modelling is based on the SDM-Site Laxemar MIKE SHE model. The modelling was divided into three steps. The first step was to update the SDM-Site Laxemar model with a new hydrogeological bedrock model. The other main updates were an increase of the depth of the MIKE SHE model domain, enhanced vertical computational resolution and that the drainage of the Aespoe Hard Rock Laboratory was included in the model. The resulting model was used to simulate undisturbed natural conditions. The next step was to describe the open repository conditions, using Laxemar layout D2, by implementing the access tunnel, the repository tunnels and shafts in the model, and to simulate the consequences for the surface hydrology caused by an open repository under different conditions. The final step was a sensitivity analysis that aimed to investigate the sensitivity of the modelled effects of the open repository to the hydrogeological properties of the bedrock and the Quaternary deposits, the sediments under the sea, and changes in boundary conditions. The model covers an area of 34 km 2 . The groundwater divides were assumed to coincide with the surface water divides; thus, a no-flow boundary condition was used at the horizontal boundaries, except in the Quaternary deposit layers towards the sea where a time-varying boundary condition describing the sea-level in the area was used. In the bedrock layers, however, a no-flow boundary condition was applied. Also the bottom boundary was described as a no-flow boundary. The transient top boundary condition was based on meteorological data gathered at

  17. Description of surface hydrology and near-surface hydrogeology at Forsmark. Site descriptive modelling SDM. Site Forsmark

    International Nuclear Information System (INIS)

    Johansson, Per-Olof

    2008-12-01

    This report describes the modelling of the surface hydrology and near-surface hydrogeology that was performed for the final site descriptive model of Forsmark produced in the site investigation stage, SDM-Site Forsmark. The comprehensive investigation and monitoring programme forms a strong basis for the developed conceptual and descriptive model of the hydrological and near-surface hydrological system of the site investigation area. However, there are some remaining uncertainties regarding the interaction of deep and near-surface groundwater and surface water of importance for the understanding of the system: The groundwaters in till below Lake Eckarfjaerden, Lake Gaellbotraesket, Lake Fiskarfjaerden and Lake Bolundsfjaerden have high salinities. The hydrological and hydrochemical interpretations indicate that these waters are relict waters of mainly marine origin. From the perspective of the overall water balance, the water below the central parts of the lakes can be considered as stagnant. However, according to the hydrochemical interpretation, these waters also contain weak signatures of deep saline water. Rough chloride budget calculations for the Gaellbotraesket depression also raise the question of a possible upward flow of deep groundwater. No absolute conclusion can be drawn from the existing data analyses regarding the key question of whether there is a small ongoing upward flow of deep saline water. However, Lake Bolundsfjaerden is an exception where the clear downward flow gradient from the till to the bedrock excludes the possibility of an active deep saline source. The available data indicate that there are no discharge areas for flow systems involving deep bedrock groundwater in the northern part of the tectonic lens, where the repository is planned to be located (the so-called 'target area'). However, it can not be excluded that such discharge areas exist. Data indicate that the prevailing downward vertical flow gradients from the QD to the bedrock

  18. Description of surface hydrology and near-surface hydrogeology at Forsmark. Site descriptive modelling SDM. Site Forsmark

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, Per-Olof (Artesia Grundvattenkonsult AB, Taeby (Sweden))

    2008-12-15

    This report describes the modelling of the surface hydrology and near-surface hydrogeology that was performed for the final site descriptive model of Forsmark produced in the site investigation stage, SDM-Site Forsmark. The comprehensive investigation and monitoring programme forms a strong basis for the developed conceptual and descriptive model of the hydrological and near-surface hydrological system of the site investigation area. However, there are some remaining uncertainties regarding the interaction of deep and near-surface groundwater and surface water of importance for the understanding of the system: The groundwaters in till below Lake Eckarfjaerden, Lake Gaellbotraesket, Lake Fiskarfjaerden and Lake Bolundsfjaerden have high salinities. The hydrological and hydrochemical interpretations indicate that these waters are relict waters of mainly marine origin. From the perspective of the overall water balance, the water below the central parts of the lakes can be considered as stagnant. However, according to the hydrochemical interpretation, these waters also contain weak signatures of deep saline water. Rough chloride budget calculations for the Gaellbotraesket depression also raise the question of a possible upward flow of deep groundwater. No absolute conclusion can be drawn from the existing data analyses regarding the key question of whether there is a small ongoing upward flow of deep saline water. However, Lake Bolundsfjaerden is an exception where the clear downward flow gradient from the till to the bedrock excludes the possibility of an active deep saline source. The available data indicate that there are no discharge areas for flow systems involving deep bedrock groundwater in the northern part of the tectonic lens, where the repository is planned to be located (the so-called 'target area'). However, it can not be excluded that such discharge areas exist. Data indicate that the prevailing downward vertical flow gradients from the QD to

  19. Characterisation of karst hydrogeology in Western Ireland using geophysical and hydraulic modelling techniques

    Directory of Open Access Journals (Sweden)

    T. McCormack

    2017-04-01

    New hydrological insights for the region: Results suggest two primary pathways of northwards groundwater flow in the catchment, a fault which discharges offshore, and a ∼2 m diameter karst conduit running underneath the catchment lowlands against the prevailing geological dip. This conduit, whose existence was suspected but never confirmed, links a large ephemeral lake to the coast where it discharges intertidally. Hydraulic modelling indicates that the conduit network is a complex mixture of constrictions with multiple inlets and outlets. Two ephemeral lakes are shown to be hydraulically discontinuous, either drained separately or linked by a low pressure channel.

  20. Combined Estimation of Hydrogeologic Conceptual Model, Parameter, and Scenario Uncertainty with Application to Uranium Transport at the Hanford Site 300 Area

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Philip D.; Ye, Ming; Rockhold, Mark L.; Neuman, Shlomo P.; Cantrell, Kirk J.

    2007-07-30

    This report to the Nuclear Regulatory Commission (NRC) describes the development and application of a methodology to systematically and quantitatively assess predictive uncertainty in groundwater flow and transport modeling that considers the combined impact of hydrogeologic uncertainties associated with the conceptual-mathematical basis of a model, model parameters, and the scenario to which the model is applied. The methodology is based on a n extension of a Maximum Likelihood implementation of Bayesian Model Averaging. Model uncertainty is represented by postulating a discrete set of alternative conceptual models for a site with associated prior model probabilities that reflect a belief about the relative plausibility of each model based on its apparent consistency with available knowledge and data. Posterior model probabilities are computed and parameter uncertainty is estimated by calibrating each model to observed system behavior; prior parameter estimates are optionally included. Scenario uncertainty is represented as a discrete set of alternative future conditions affecting boundary conditions, source/sink terms, or other aspects of the models, with associated prior scenario probabilities. A joint assessment of uncertainty results from combining model predictions computed under each scenario using as weight the posterior model and prior scenario probabilities. The uncertainty methodology was applied to modeling of groundwater flow and uranium transport at the Hanford Site 300 Area. Eight alternative models representing uncertainty in the hydrogeologic and geochemical properties as well as the temporal variability were considered. Two scenarios represent alternative future behavior of the Columbia River adjacent to the site were considered. The scenario alternatives were implemented in the models through the boundary conditions. Results demonstrate the feasibility of applying a comprehensive uncertainty assessment to large-scale, detailed groundwater flow

  1. Mathematical numeric models for assessing the groundwater pollution from Sanitary landfills

    Science.gov (United States)

    Petrov, Vasil; Stoyanov, Nikolay; Sotinev, Petar

    2014-05-01

    Landfills are among the most common sources of pollution in ground water. Their widespread deployment, prolonged usage and the serious damage they cause to all of the elements of the environment are the reasons, which make the study of the problem particularly relevant. Most dangerous of all are the open dumps used until the middle of the twentieth century, from which large amounts of liquid emissions flowed freely (landfill infiltrate). In recent decades, the problem is solved by the construction of sanitary landfills in which they bury waste or solid residue from waste utilization plants. The bottom and the sides of the sanitary landfills are covered with a protective waterproof screen made of clay and polyethylene and the landfill infiltrate is led outside through a drainage system. This method of disposal severely limits any leakage of gas and liquid emissions into the environment and virtually eliminates the possibility of contamination. The main topic in the conducted hydrogeological study was a quantitative assessment of groundwater pollution and the environmental effects of re-landfilling of an old open dump into a new sanitary landfill, following the example of the municipal landfill of Asenovgrad, Bulgaria. The study includes: 1.A set of drilling, geophysical and hydrogeological field and laboratory studies on: -the definition and designation of the spatial limits of the main hydrogeological units; -identification of filtration parameters and migration characteristics of the main hydrogeological units; -clarifying the conditions for the sustentation and drainage of groundwater; -determininng the structure of the filtration field; -identifying and assessing the size and the extent of groundwater contamination from the old open dump . 2.Mathematical numeric models of migration and entry conditions of contaminants below the bottom of the landfill unit, with which the natural protection of the geological environment, the protective effect of the engineering

  2. Hydrogeological characterisation of groundwater over Brazil using remotely sensed and model products.

    Science.gov (United States)

    Hu, Kexiang; Awange, Joseph L; Khandu; Forootan, Ehsan; Goncalves, Rodrigo Mikosz; Fleming, Kevin

    2017-12-01

    For Brazil, a country frequented by droughts and whose rural inhabitants largely depend on groundwater, reliance on isotope for its monitoring, though accurate, is expensive and limited in spatial coverage. We exploit total water storage (TWS) derived from Gravity Recovery and Climate Experiment (GRACE) satellites to analyse spatial-temporal groundwater changes in relation to geological characteristics. Large-scale groundwater changes are estimated using GRACE-derived TWS and altimetry observations in addition to GLDAS and WGHM model outputs. Additionally, TRMM precipitation data are used to infer impacts of climate variability on groundwater fluctuations. The results indicate that climate variability mainly controls groundwater change trends while geological properties control change rates, spatial distribution, and storage capacity. Granular rocks in the Amazon and Guarani aquifers are found to influence larger storage capability, higher permeability (>10 -4 m/s) and faster response to rainfall (1 to 3months' lag) compared to fractured rocks (permeability 3months) found only in Bambui aquifer. Groundwater in the Amazon region is found to rely not only on precipitation but also on inflow from other regions. Areas beyond the northern and southern Amazon basin depict a 'dam-like' pattern, with high inflow and slow outflow rates (recharge slope > 0.75, discharge slope 30cm). Amazon's groundwater declined between 2002 and 2008 due to below normal precipitation (wet seasons lasted for about 36 to 47% of the time). The Guarani aquifer and adjacent coastline areas rank second in terms of storage capacity, while the northeast and southeast coastal regions indicate the smallest storage capacity due to lack of rainfall (annual average is rainfall <10cm). Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Large scale experiments as a tool for numerical model development

    DEFF Research Database (Denmark)

    Kirkegaard, Jens; Hansen, Erik Asp; Fuchs, Jesper

    2003-01-01

    Experimental modelling is an important tool for study of hydrodynamic phenomena. The applicability of experiments can be expanded by the use of numerical models and experiments are important for documentation of the validity of numerical tools. In other cases numerical tools can be applied...

  4. Numerical modelling of new rockfall interception nets

    Science.gov (United States)

    von Boetticher, Albrecht; Volkwein, Axel; Wendeler, Corinna

    2010-05-01

    The design and certification of effective rockfall protection barriers is mainly achieved through 1:1 prototype testing. In order to reduce development costs of a prototype it is recommended that pre-studies using numerical simulations are performed. A large component to modelling rockfall protection systems is the numerical simulation of the nets. To date there exist several approaches to model the different mesh types such as ring nets or diagonal meshes (Nicot 1999, Cazzani et al. 2002, Volkwein 2004). However, the consideration of chain link meshes has not yet been realised. Chain link meshes are normally found as standard fence structures. However, they also exist in setups using high-strength steel and wire bundles. These variants show an enormous capacity to retain loads e.g. rockfalls, and at the same time are very efficient due to their low demand of steel material. The increasing application of chain link mesh in barrier systems requires an accurate model is available to complete prototype studies. A new approach now aims to perform a Finite Element simulation of such chain link meshes. The main challenge herein is to achieve the net deformation behaviour that is observed in field tests also in the simulation. A simulation using simple truss elements would not work since it neglects the out-of-plane-height of the mesh construction providing important reserves for local and global high deformations. Thus addressing this, a specially developed Discrete Element is able to reconstruct the mechanical behaviour of the single chain wire (bundles). As input parameters it utilises typical properties such as longitudinal and transversal mesh widths, and break loads resulting from in-plane-tension tests and steel strength. The single chain elements then can be combined to a complete mesh (e.g. 130 x 65 mm, 3 - 4 mm wire with a strength of 1770 N-mm2). Combining these elements with a supporting structure consisting of posts, ropes and energy absorbers, enables the

  5. Numerical models for high beta magnetohydrodynamic flow

    International Nuclear Information System (INIS)

    Brackbill, J.U.

    1987-01-01

    The fundamentals of numerical magnetohydrodynamics for highly conducting, high-beta plasmas are outlined. The discussions emphasize the physical properties of the flow, and how elementary concepts in numerical analysis can be applied to the construction of finite difference approximations that capture these features. The linear and nonlinear stability of explicit and implicit differencing in time is examined, the origin and effect of numerical diffusion in the calculation of convective transport is described, and a technique for maintaining solenoidality in the magnetic field is developed. Many of the points are illustrated by numerical examples. The techniques described are applicable to the time-dependent, high-beta flows normally encountered in magnetically confined plasmas, plasma switches, and space and astrophysical plasmas. 40 refs

  6. Numerical modelling of nearshore wave transformation

    Digital Repository Service at National Institute of Oceanography (India)

    Chandramohan, P.; Nayak, B.U.; SanilKumar, V.

    A software has been developed for numerical refraction study based on finite amplitude wave theories. Wave attenuation due to shoaling, bottom friction, bottom percolation and viscous dissipation has also been incorporated. The software...

  7. Numerical modelling of multicomponent LNAPL dissolution kinetics ...

    Indian Academy of Sciences (India)

    subsequent removal of free phase liquid, still the organic compounds are present .... Since the flow through porous media is mainly restricted to the pore space ..... initial and boundary conditions for the numerical scheme are given in table 2.

  8. Summary of hydrogeologic conditions at Aberg, Beberg and Ceberg

    Energy Technology Data Exchange (ETDEWEB)

    Walker, D.; Gurban, I. [INTERA KB, Sollentuna (Sweden); Rhen, I. [VBB Viak AB (Sweden)

    1997-10-01

    This report is a compilation of existing data and descriptions for use in the hydrogeologic modelling of three hypothetical sites for a nuclear waste repository in Sweden. It provides modelling teams with preliminary conceptual models, parameter values and uncertainties for inputs to numerical flow and transport models on the regional and site scales. Its primary objective is to provide consistent data sets and conceptual models so that the results of performance assessment modelling will be as comparable as possible. Where possible, this report also provides alternative conceptual models that should be evaluated as part of the modelers` sensitivity analysis. The information contained in this report is taken from several key sources, including the SKB SICADA database, the Swedish Geological Survey well database, the SKB Geographic Information System, the Swedish Land Survey databases, and published SKB reports. 148 refs, 25 tabs, 60 figs.

  9. Summary of hydrogeologic conditions at Aberg, Beberg and Ceberg

    International Nuclear Information System (INIS)

    Walker, D.; Gurban, I.; Rhen, I.

    1997-10-01

    This report is a compilation of existing data and descriptions for use in the hydrogeologic modelling of three hypothetical sites for a nuclear waste repository in Sweden. It provides modelling teams with preliminary conceptual models, parameter values and uncertainties for inputs to numerical flow and transport models on the regional and site scales. Its primary objective is to provide consistent data sets and conceptual models so that the results of performance assessment modelling will be as comparable as possible. Where possible, this report also provides alternative conceptual models that should be evaluated as part of the modelers' sensitivity analysis. The information contained in this report is taken from several key sources, including the SKB SICADA database, the Swedish Geological Survey well database, the SKB Geographic Information System, the Swedish Land Survey databases, and published SKB reports

  10. Numerical Modelling of Sediment Transport in Combined Sewer Systems

    DEFF Research Database (Denmark)

    Schlütter, Flemming

    A conceptual sediment transport model has been developed. Through a case study a comparison with other numerical models is performed.......A conceptual sediment transport model has been developed. Through a case study a comparison with other numerical models is performed....

  11. A numerical 4D Collision Risk Model

    Science.gov (United States)

    Schmitt, Pal; Culloch, Ross; Lieber, Lilian; Kregting, Louise

    2017-04-01

    With the growing number of marine renewable energy (MRE) devices being installed across the world, some concern has been raised about the possibility of harming mobile, marine fauna by collision. Although physical contact between a MRE device and an organism has not been reported to date, these novel sub-sea structures pose a challenge for accurately estimating collision risks as part of environmental impact assessments. Even if the animal motion is simplified to linear translation, ignoring likely evasive behaviour, the mathematical problem of establishing an impact probability is not trivial. We present a numerical algorithm to obtain such probability distributions using transient, four-dimensional simulations of a novel marine renewable device concept, Deep Green, Minesto's power plant and hereafter referred to as the 'kite' that flies in a figure-of-eight configuration. Simulations were carried out altering several configurations including kite depth, kite speed and kite trajectory while keeping the speed of the moving object constant. Since the kite assembly is defined as two parts in the model, a tether (attached to the seabed) and the kite, collision risk of each part is reported independently. By comparing the number of collisions with the number of collision-free simulations, a probability of impact for each simulated position in the cross- section of the area is considered. Results suggest that close to the bottom, where the tether amplitude is small, the path is always blocked and the impact probability is 100% as expected. However, higher up in the water column, the collision probability is twice as high in the mid line, where the tether passes twice per period than at the extremes of its trajectory. The collision probability distribution is much more complex in the upper end of the water column, where the kite and tether can simultaneously collide with the object. Results demonstrate the viability of such models, which can also incorporate empirical

  12. Numerical modeling of seawater intrusion in Zhoushuizi district of Dalian City, China

    Science.gov (United States)

    Zhao, J.; Lin, J.; Wu, J.

    2013-12-01

    A three-dimensional heterogeneous density-dependent numerical model was constructed to simulate the seawater intrusion process in coastal aquifers in Zhoushuizi Region, Dalian City. Model calibration was achieved through a prediction-correction method by adjusting the zonation and values of hydrogeologic parameters until the calculated heads and concentrations matched the observed values. Model validation results also showed that it was reasonable under current data conditions. Then the calibrated and validated model was applied to predict the dynamics and trend of seawater intrusion according to the current groundwater abstraction conditions in this study area 30 years after 2010. Prediction results showed that overall seawater intrusion in the future would be even more severe. Actually, with the growing of the population and development of the economy, the demand for ground water will be increasing continuously so that the problem of seawater intrusion may be more serious than that predicted by the modelin this study. Better strategies for reasonably governing exploitation of groundwater in the study area can be further developed by using this three-dimensional seawater intrusion model.

  13. Numerical

    Directory of Open Access Journals (Sweden)

    M. Boumaza

    2015-07-01

    Full Text Available Transient convection heat transfer is of fundamental interest in many industrial and environmental situations, as well as in electronic devices and security of energy systems. Transient fluid flow problems are among the more difficult to analyze and yet are very often encountered in modern day technology. The main objective of this research project is to carry out a theoretical and numerical analysis of transient convective heat transfer in vertical flows, when the thermal field is due to different kinds of variation, in time and space of some boundary conditions, such as wall temperature or wall heat flux. This is achieved by the development of a mathematical model and its resolution by suitable numerical methods, as well as performing various sensitivity analyses. These objectives are achieved through a theoretical investigation of the effects of wall and fluid axial conduction, physical properties and heat capacity of the pipe wall on the transient downward mixed convection in a circular duct experiencing a sudden change in the applied heat flux on the outside surface of a central zone.

  14. Hydrogeology of Mors

    International Nuclear Information System (INIS)

    Joshi, A.V.

    1982-01-01

    The covering layers protect the salt in the dome. Ground water velocities are small and the chalk exhibits good retention properties for the radionuclides. As ground water velocities below 500 m are small, knowledge of hydrogeology over only a small area over the dome is necessary (1 km horizontal transport takes about 15 mill. years). Additionally if the retention properties of the chalk together with radioactive decay are taken into account, it becomes obvious that the nuclides can travel only a few metres into the chalk, before they have decayed to safe radioactive levels. Therefore it does not appear to be necessary to investigate the hydrogeology beyond a few metres from the disposal area. The hydrogeological investigations that have been carried out, although they cover only a limited area, thus give an excellent and sufficient basis for a safety evaluation for determining the suitability of the Mors salt dome for waste disposal. (EG)

  15. Masonry constructions mechanical models and numerical applications

    CERN Document Server

    Lucchesi, Massimiliano; Padovani, Cristina

    2008-01-01

    Numerical methods for the structural analysis of masonry constructions can be of great value in assessing the safety of artistically important masonry buildings and optimizing potential operations of maintenance and strengthening in terms of their cost-effectiveness, architectural impact and static effectiveness. This monograph firstly provides a detailed description of the constitutive equation of masonry-like materials, clearly setting out its most important features. It then goes on to provide a numerical procedure to solve the equilibrium problem of masonry solids. A large portion of the w

  16. Numerical considerations for Lagrangian stochastic dispersion models: Eliminating rogue trajectories, and the importance of numerical accuracy

    Science.gov (United States)

    When Lagrangian stochastic models for turbulent dispersion are applied to complex flows, some type of ad hoc intervention is almost always necessary to eliminate unphysical behavior in the numerical solution. This paper discusses numerical considerations when solving the Langevin-based particle velo...

  17. Some Experiences with Numerical Modelling of Overflows

    DEFF Research Database (Denmark)

    Larsen, Torben; Nielsen, L.; Jensen, B.

    2007-01-01

    across the edge of the overflow. To ensure critical flow across the edge, the upstream flow must be subcritical whereas the downstream flow is either supercritical or a free jet. Experimentally overflows are well studied. Based on laboratory experiments and Froude number scaling, numerous accurate...

  18. Numerical time integration for air pollution models

    NARCIS (Netherlands)

    J.G. Verwer (Jan); W. Hundsdorfer (Willem); J.G. Blom (Joke)

    1998-01-01

    textabstractDue to the large number of chemical species and the three space dimensions, off-the-shelf stiff ODE integrators are not feasible for the numerical time integration of stiff systems of advection-diffusion-reaction equations [ fracpar{c{t + nabla cdot left( vu{u c right) = nabla cdot left(

  19. Numerical modeling and the physical basis of seismic discriminants

    International Nuclear Information System (INIS)

    Denny, M.D.

    1993-01-01

    Accurate seismic event discrimination is critical to detection of nuclear explosions. Numerical modeling applied to seismic event discrimination can lead to increased reliability of proliferation detection. It is particularly applicable to error budgeting and to understanding explosion and earthquake phenomenologies. There also is a need for minimum requirements to validate the models used in numerical modeling

  20. 2-dimensional numerical modeling of active magnetic regeneration

    DEFF Research Database (Denmark)

    Nielsen, Kaspar Kirstein; Pryds, Nini; Smith, Anders

    2009-01-01

    Various aspects of numerical modeling of Active Magnetic Regeneration (AMR) are presented. Using a 2-dimensional numerical model for solving the unsteady heat transfer equations for the AMR system, a range of physical effects on both idealized and non-idealized AMR are investigated. The modeled...

  1. Bedrock Hydrogeology - Site investigation SFR

    Energy Technology Data Exchange (ETDEWEB)

    Oehman, Johan [Geosigma AB, Stockholm (Sweden); Bockgaard, Niclas [Golder Assoes AB, Stockholm (Sweden); Follin, Sven [SF GeoLogic AB, Taeby (Sweden)

    2012-06-15

    The Swedish Nuclear Fuel and Waste Management Company (SKB) has conducted site investigations for a planned extension of the existing final repository for short-lived radioactive waste (SFR). This report presents an integrated analysis and interpretation of the historic data from the existing SFR (1980 - 1986), as well as, from the recent investigations for the planned extension of SFR (2008 - 2009). The primary objective is to establish a conceptual hydrogeological model of the bedrock for safety assessment and design analyses. Analyses and interpretations of all (old and new) hydraulic data are analysed with regard to the recently developed geological deformation zone model of the SFR model domain (Curtis et al. 2011). The methodology used by Curtis et al. (2011) has focussed on magnetic anomalies and deformation zone intercepts with ground surface greater than 300 m. In the hydrogeological modelling, however, it has been considered important to also explore the occurrence and characteristics of shallow horizontal to sub-horizontal structures (sheet joints) inside the SFR model domain. Such structures are of considerable importance for the hydrogeology in the uppermost c. 150 m of bedrock in SDM-Site Forsmark; hence the term Shallow Bedrock Aquifer was used to emphasise their hydraulic significance. In this study, the acronym SBA-structure is used for horizontal structures identified in the hydrogeological modelling. In addition to the predominantly steeply dipping geological deformation zones, eight so-called SBA-structures are modelled deterministically in the hydrogeological model. The SBA-structures are envisaged as hydraulically heterogeneous and composed of clusters of minor gently dipping to horizontal fractures rather than extensive single features. A type of structures that is partly included in the definition of the SBA-structures is the Unresolved Possible Deformations Zone (Unresolved PDZ) intercepts identified by Curtis et al. (2011). The Unresolved

  2. Conceptual and Numerical Models for UZ Flow and Transport

    International Nuclear Information System (INIS)

    Liu, H.

    2000-01-01

    The purpose of this Analysis/Model Report (AMR) is to document the conceptual and numerical models used for modeling of unsaturated zone (UZ) fluid (water and air) flow and solute transport processes. This is in accordance with ''AMR Development Plan for U0030 Conceptual and Numerical Models for Unsaturated Zone (UZ) Flow and Transport Processes, Rev 00''. The conceptual and numerical modeling approaches described in this AMR are used for models of UZ flow and transport in fractured, unsaturated rock under ambient and thermal conditions, which are documented in separate AMRs. This AMR supports the UZ Flow and Transport Process Model Report (PMR), the Near Field Environment PMR, and the following models: Calibrated Properties Model; UZ Flow Models and Submodels; Mountain-Scale Coupled Processes Model; Thermal-Hydrologic-Chemical (THC) Seepage Model; Drift Scale Test (DST) THC Model; Seepage Model for Performance Assessment (PA); and UZ Radionuclide Transport Models

  3. Characterization of hydrogeologic units using matrix properties, Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Flint, L.E.

    1998-01-01

    Determination of the suitability of Yucca Mountain, in southern Nevada, as a geologic repository for high-level radioactive waste requires the use of numerical flow and transport models. Input for these models includes parameters that describe hydrologic properties and the initial and boundary conditions for all rock materials within the unsaturated zone, as well as some of the upper rocks in the saturated zone. There are 30 hydrogeologic units in the unsaturated zone, and each unit is defined by limited ranges where a discrete volume of rock contains similar hydrogeologic properties. These hydrogeologic units can be easily located in space by using three-dimensional lithostratigraphic models based on relationships of the properties with the lithostratigraphy. Physical properties of bulk density, porosity, and particle density; flow properties of saturated hydraulic conductivity and moisture-retention characteristics; and the state variables (variables describing the current state of field conditions) of saturation and water potential were determined for each unit. Units were defined using (1) a data base developed from 4,892 rock samples collected from the coring of 23 shallow and 8 deep boreholes, (2) described lithostratigraphic boundaries and corresponding relations to porosity, (3) recognition of transition zones with pronounced changes in properties over short vertical distances, (4) characterization of the influence of mineral alteration on hydrologic properties such as permeability and moisture-retention characteristics, and (5) a statistical analysis to evaluate where boundaries should be adjusted to minimize the variance within layers. This study describes the correlation of hydrologic properties to porosity, a property that is well related to the lithostratigraphy and depositional and cooling history of the volcanic deposits and can, therefore, be modeled to be distributed laterally

  4. Chemical analysis of water in hydrogeology

    International Nuclear Information System (INIS)

    Flakova, R.; Zenisova, Z.; Seman, M.

    2010-01-01

    The aim of the monograph is to give complete information on the chemical analysis of water hydrogeology not only for the students program of Geology study (Bachelor degree study), Engineering Geology and Hydrogeology (Master's degree study) and Engineering Geology (doctoral level study), but also for students from other colleges and universities schools in Slovakia, as well as in the Czech Republic, dealing with the chemical composition of water and its quality, from different perspectives. The benefit would be for professionals with hydrogeological, water and environmental practices, who can find there all the necessary information about proper water sampling, the units used in the chemical analysis of water, expressing the proper chemical composition of water in its various parameters through classification of chemical composition of the water up to the basic features of physical chemistry at thermodynamic calculations and hydrogeochemical modelling.

  5. Inventory and review of existing PRISM hydrogeologic data for the Islamic Republic of Mauritania, Africa

    Science.gov (United States)

    Friedel, Michael J.

    2008-01-01

    The USGS entered into an agreement with the Mauritania Ministry of Mines and Industry to inventory and review the quality of information collected as part of the Project for Strengthening of the Institutions in the Mining Sector (PRISM). Whereas the PRISM program collected geophysical, geochemical, geological, satellite, and hydrogeologic information, this report focuses on an inventory and review of available hydrogeologic data provided to the USGS in multiple folders, files, and formats. Most of the information pertained to the hydrogeologic setting and the water budget of evaporation, evapotranspiration, and precipitation in the Choum-Zouerate area in northwestern Mauritania, and the country of Mauritania itself. Other information about the quantity and quality of groundwater was found in the relational Access database. In its present form, the limited hydrogeologic information was not amenable to conducting water balance, geostatistical, and localized numerical modeling studies in support of mineral exploration and development. Suggestions are provided to remedy many of the data's shortcomings, such as performing quality assurance on all SIPPE2 data tables and sending questionnaires to appropriate agencies, mining and other companies to populate the database with additional meteorology, hydrology, and groundwater data.

  6. Numerical Models of Sewage Dispersion and Statistica Bathing Water Standards

    DEFF Research Database (Denmark)

    Petersen, Ole; Larsen, Torben

    1991-01-01

    As bathing water standards usually are founded in statistical methods, the numerical models used in outfall design should reflect this. A statistical approach, where stochastic variations in source strength and bacterial disappearance is incorporated into a numerical dilution model is presented. ...

  7. An approach to hydrogeological modeling of a large system of groundwater-fed lakes and wetlands in the Nebraska Sand Hills, USA

    Science.gov (United States)

    Rossman, Nathan R.; Zlotnik, Vitaly A.; Rowe, Clinton M.

    2018-05-01

    The feasibility of a hydrogeological modeling approach to simulate several thousand shallow groundwater-fed lakes and wetlands without explicitly considering their connection with groundwater is investigated at the regional scale ( 40,000 km2) through an application in the semi-arid Nebraska Sand Hills (NSH), USA. Hydraulic heads are compared to local land-surface elevations from a digital elevation model (DEM) within a geographic information system to assess locations of lakes and wetlands. The water bodies are inferred where hydraulic heads exceed, or are above a certain depth below, the land surface. Numbers of lakes and/or wetlands are determined via image cluster analysis applied to the same 30-m grid as the DEM after interpolating both simulated and estimated heads. The regional water-table map was used for groundwater model calibration, considering MODIS-based net groundwater recharge data. Resulting values of simulated total baseflow to interior streams are within 1% of observed values. Locations, areas, and numbers of simulated lakes and wetlands are compared with Landsat 2005 survey data and with areas of lakes from a 1979-1980 Landsat survey and the National Hydrography Dataset. This simplified process-based modeling approach avoids the need for field-based morphology or water-budget data from individual lakes or wetlands, or determination of lake-groundwater exchanges, yet it reproduces observed lake-wetland characteristics at regional groundwater management scales. A better understanding of the NSH hydrogeology is attained, and the approach shows promise for use in simulations of groundwater-fed lake and wetland characteristics in other large groundwater systems.

  8. Mathematical modelling and numerical simulation of casting processes

    DEFF Research Database (Denmark)

    Hattel, Jesper Henri

    1998-01-01

    The control volume method applied to numerical modelling of castning. Analytical solutions based on the error function.Riemann-temperature. Modelling of release of latent heat with the enthalpy method....

  9. Numerical model of the catchments of the oziąbel and wołczyński strumień rivers - Wołczyn municipality

    Science.gov (United States)

    Olichwer, Tomasz; Wcisło, Marek; Staśko, Stanisław; Buczyński, Sebastian; Modelska, Magdalena; Tarka, Robert

    2012-10-01

    The article presents a numerical model designed for determining groundwater dynamics and water balance of the catchments of the Oziąbel (Czarna Woda) river and the Wołczyński Strumień river in Wołczyn region. Hydrogeological mapping and modelling research covered the area of 238.9 km2. As a result of measurements performed in 2008-2009, flows were determined in major rivers and water table positions were measured at 26 points. In the major part of the area described, the water table, lying at the depth of 1.5-18.7 m, has unconfined character, and the aquifer is built of Neogene (Quaternary) sands and gravels. In the area under study, groundwaters are drawn from 6 wells with total withdrawal of 6133 m3/d. The numerical modelling was performed with the use of Visual Modflow 3.1.0 software. The area was partitioned by a discretization grid with a step size l = 250 m. The conceptual model of the hydrogeological system is based on hydrological data gathered over a period of one year, data from HYDRO bank database, cross-sections and maps. The boundaries of the modelled hydrogeological system were established on the watersheds of the Wołczyński Strumień river and the Oziąbel river, apart from the areas where they run together. The modelled area was extended (271.5 km2) around the Wołczyński Strumień river catchment to achieve a more effective mapping of the anthropogenic impact on its balance and the hydrodynamic system of the catchment area. The structure is characterised by the occurrence of one or rarely two aquifers separated by a pack of Quaternary clays. The investigation produced a detailed water balance and its components.

  10. A numerical model of heavy gas dispersion

    International Nuclear Information System (INIS)

    Bidokhtti, A.A.

    1993-01-01

    A simple mathematical model describing the motion of a dense gas released continuously into and environment is presented. The model correctly predicts the laboratory experiments which were carried out by Britter and Snyder (1987). It is an entrainment model better known as box model. In this model, the effects of temperature change and phase change are not considered and it is for a steady-state case. Further work is required for including these effects which are often associated with the mechanisms involved in accidental or natural release of heavy gases in the environment. The results of such a model will be extended to the practical situations which are and will be common to the nuclear industry at the Atomic Energy Organization of Iran. The applicability of such studies to these situations will be discussed

  11. Numerical Model of High Strength Concrete

    Science.gov (United States)

    Wang, R. Z.; Wang, C. Y.; Lin, Y. L.

    2018-03-01

    The purpose of this paper is to present a three-dimensional constitutive model based on the concept of equivalent uniaxial strain. closed Menetrey-Willam (CMW) failure surfaces which combined with Menetrey-Willam meridian and the cap model are introduced in this paper. Saenz stress-strain model is applied and adjusted by the ultimate strength parameters from CMW failure surface to reflect the latest stress or strain condition. The high strength concrete (HSC) under tri-axial non-proportional loading is considered and the model in this paper performed a good prediction.

  12. Numerical modeling of ground-water flow systems in the vicinity of the reference repository location, Hanford Site, Washington

    International Nuclear Information System (INIS)

    Davis, P.; Beyeler, W.; Logsdon, M.; Coleman, N.; Brinster, K.

    1989-04-01

    This report documents south-central Washington State's Pasco Basin ground-water modeling studies. This work was done to support the NRC's review of hydrogeologic studies under the Department of Energy's (DOE) Basalt Waste Isolation Project. The report provides a brief overview of the geology, hydrology, and hydrochemistry of the Pasco Basin as a basis for the evaluation of previous conceptual and numerical ground-water flow models of the region. Numerical models were developed to test new conceptual models of the site and to provide a means of evaluating the Department of Energy's performance assessments and proposed hydrologic testing. Regional ground-water flow modeling of an area larger than the Pasco Basin revealed that current concepts on the existence and behavior of a hydrologic barrier west of the proposed repository location are inconsistent with available data. This modeling also demonstrated that the measured pattern of hydraulic heads cannot be produced with a model that (1) has uniform layer properties over the entire domain; (2) has zones of large conductivity associated with anticlinal structures; or (3) includes recharge from the industrial disposal ponds. Adequate representation of the measured hydraulic heads was obtained with a model that contained regions of larger hydraulic conductivity that corresponded to the presence of sedimentary interbeds. In addition, a detailed model of a region smaller than the Pasco Basin was constructed to provide the NRC staff with the ability to analyze proposed Department of Energy hydrologic tests. 62 refs., 145 figs., 18 tabs

  13. Numerical model of Ca(OH)

    NARCIS (Netherlands)

    Koster, T.; Peelen, W.; Larbi, J.; Rooij, M. de; Polder, R.

    2010-01-01

    A mathematical model is being developed to describe a repair method in concrete, called cathodic protection (CP). The model is in principle also useful to describe electrodeposition in concrete, e.g. the process of re-precipitation of Ca(OH)2 invoked by an electrical current. In CP, the

  14. Numerical Modelling of Wave Run-Up

    DEFF Research Database (Denmark)

    Ramirez, Jorge Robert Rodriguez; Frigaard, Peter; Andersen, Thomas Lykke

    2011-01-01

    Wave loads are important in problems related to offshore structure, such as wave run-up, slamming. The computation of such wave problems are carried out by CFD models. This paper presents one model, NS3, which solve 3D Navier-Stokes equations and use Volume of Fluid (VOF) method to treat the free...

  15. Improving stability of regional numerical ocean models

    Science.gov (United States)

    Herzfeld, Mike

    2009-02-01

    An operational limited-area ocean modelling system was developed to supply forecasts of ocean state out to 3 days. This system is designed to allow non-specialist users to locate the model domain anywhere within the Australasian region with minimum user input. The model is required to produce a stable simulation every time it is invoked. This paper outlines the methodology used to ensure the model remains stable over the wide range of circumstances it might encounter. Central to the model configuration is an alternative approach to implementing open boundary conditions in a one-way nesting environment. Approximately 170 simulations were performed on limited areas in the Australasian region to assess the model stability; of these, 130 ran successfully with a static model parameterisation allowing a statistical estimate of the model’s approach toward instability to be determined. Based on this, when the model was deemed to be approaching instability a strategy of adaptive intervention in the form of constraint on velocity and elevation was invoked to maintain stability.

  16. Hydrogeological and Hydrogeochemical Modelling of the Alicun de las Torres Termal System (Province of Granada). Isotope Hydrochemistry and Gases in Groundwaters

    International Nuclear Information System (INIS)

    Prado Perez, A. J.; Delgado, A.; Crespo, M. T.; Martin, A.; Vaselli, O.; Perez del Villar, L.

    2010-01-01

    In the framework of a Singular Strategic Project entitled: A dvanced Technologies of Carbon, Capture and Storage (CCS) , supported by the MICINN (Spain) and the FEDER founds (EU), specifically in the Carbon Storage Task, a comprehensive study on the CO 2 leakage as DIC (Dissolved Inorganic Carbon) in the Alicun de Las Torres (Prov. of Granada) natural analogue thermal system was envisaged. This analogous system is characterised by the presence of a very important travertine formation, which can be considered as a permanent and stable sink for CO 2 . In order to explain the formation of these travertine mass an hydrogeological and hydrogeochemical model of the area has been established by using the hydrochemical data, the stable and radioactive isotope characteristics, the dissolved inorganic carbon, as well as the chemical and isotopic composition of the free and dissolved gases of the above mentioned Thermal System. (Author) 11 refs.

  17. Numerical Modelling of Structures with Uncertainties

    Directory of Open Access Journals (Sweden)

    Kahsin Maciej

    2017-04-01

    Full Text Available The nature of environmental interactions, as well as large dimensions and complex structure of marine offshore objects, make designing, building and operation of these objects a great challenge. This is the reason why a vast majority of investment cases of this type include structural analysis, performed using scaled laboratory models and complemented by extended computer simulations. The present paper focuses on FEM modelling of the offshore wind turbine supporting structure. Then problem is studied using the modal analysis, sensitivity analysis, as well as the design of experiment (DOE and response surface model (RSM methods. The results of modal analysis based simulations were used for assessing the quality of the FEM model against the data measured during the experimental modal analysis of the scaled laboratory model for different support conditions. The sensitivity analysis, in turn, has provided opportunities for assessing the effect of individual FEM model parameters on the dynamic response of the examined supporting structure. The DOE and RSM methods allowed to determine the effect of model parameter changes on the supporting structure response.

  18. Paleoclimate validation of a numerical climate model

    International Nuclear Information System (INIS)

    Schelling, F.J.; Church, H.W.; Zak, B.D.; Thompson, S.L.

    1994-01-01

    An analysis planned to validate regional climate model results for a past climate state at Yucca Mountain, Nevada, against paleoclimate evidence for the period is described. This analysis, which will use the GENESIS model of global climate nested with the RegCM2 regional climate model, is part of a larger study for DOE's Yucca Mountain Site Characterization Project that is evaluating the impacts of long term future climate change on performance of the potential high level nuclear waste repository at Yucca Mountain. The planned analysis and anticipated results are presented

  19. Amorphous track models: a numerical comparison study

    DEFF Research Database (Denmark)

    Greilich, Steffen; Grzanka, Leszek; Hahn, Ute

    in carbon ion treatment at the particle facility HIT in Heidelberg. Apparent differences between the LEM and the Katz model are the way how interactions of individual particle tracks and how extended targets are handled. Complex scenarios, however, can mask the actual effect of these differences. Here, we......Amorphous track models such as Katz' Ion-Gamma-Kill (IGK) approach [1, 2] or the Local Effect Model (LEM) [3, 4] had reasonable success in predicting the response of solid state dosimeters and radiobiological systems. LEM is currently applied in radiotherapy for biological dose optimization...

  20. NUMERICAL SIMULATION AND MODELING OF UNSTEADY FLOW ...

    African Journals Online (AJOL)

    2014-06-30

    Jun 30, 2014 ... objective of this study is to control the simulation of unsteady flows around structures. ... Aerospace, our results were in good agreement with experimental .... Two-Equation Eddy-Viscosity Turbulence Models for Engineering.

  1. Computational numerical modelling of plasma focus

    International Nuclear Information System (INIS)

    Brollo, Fabricio

    2005-01-01

    Several models for calculation of the dynamics of Plasma Focus have been developed. All of them begin from the same physic principle: the current sheet run down the anode length, ionizing and collecting the gas that finds in its way.This is known as snow-plow model.Concerning pinch's compression, a MHD model is proposed.The plasma is treated as a fluid , particularly as a high ionized gas.However, there are not many models that, taking into account thermal equilibrium inside the plasma, make approximated calculations of the maximum temperatures reached in the pinch.Besides, there are no models which use those temperatures to estimate the termofusion neutron yield for the Deuterium or Deuterium-Tritium gas filled cases.In the PLADEMA network (Dense Magnetized Plasmas) a code was developed with the objective of describe the plasma focus dynamics, in a conceptual engineering stage.The codes calculates the principal variables (currents, time to focus, etc) and estimates the neutron yield in Deuterium-filled plasma focus devices.It can be affirmed that the code's experimental validation, in its axial and radial stages, was very successfully. However, it was accepted that the compression stage should be formulated again, to find a solution for a large variation of a parameter related with velocity profiles for the particles trapped inside the pinch.The objectives of this work can be stated in the next way : - Check the compression's model hypothesis. Develop a new model .- Implement the new model in the code. Compare results against experimental data of Plasma Focus devices from all around the world [es

  2. The influence of numerical models on determining the drag coefficient

    Directory of Open Access Journals (Sweden)

    Dobeš Josef

    2014-03-01

    Full Text Available The paper deals with numerical modelling of body aerodynamic drag coefficient in the transition from laminar to turbulent flow regimes, where the selection of a suitable numerical model is problematic. On the basic problem of flow around a simple body – sphere selected computational models are tested. The values obtained by numerical simulations of drag coefficients of each model are compared with the graph of dependency of the drag coefficient vs. Reynolds number for a sphere. Next the dependency of Strouhal number vs. Reynolds number is evaluated, where the vortex shedding frequency values for given speed are obtained numerically and experimentally and then the values are compared for each numerical model and experiment. The aim is to specify trends for the selection of appropriate numerical model for flow around bodies problem in which the precise description of the flow field around the obstacle is used to define the acoustic noise source. Numerical modelling is performed by finite volume method using CFD code.

  3. Numerical modelling of laser rapid prototyping by fusion wire deposit

    OpenAIRE

    Arbaoui , Larbi; Masse , J.E.; Barrallier , Laurent; Mocellin , Katia

    2010-01-01

    International audience; A finite element model has been developed to simulate an innovative laser rapid prototyping process. Several numerical developments have been implemented in order to simulate the main steps of the rapid prototyping process: injection, heating, phase change and deposit. The numerical model also takes into account different phenomena: surface tension in the liquid state, asborptivity and plasma effects during materiallaser interaction. The threedimensional model is based...

  4. Evaluation of wave runup predictions from numerical and parametric models

    Science.gov (United States)

    Stockdon, Hilary F.; Thompson, David M.; Plant, Nathaniel G.; Long, Joseph W.

    2014-01-01

    Wave runup during storms is a primary driver of coastal evolution, including shoreline and dune erosion and barrier island overwash. Runup and its components, setup and swash, can be predicted from a parameterized model that was developed by comparing runup observations to offshore wave height, wave period, and local beach slope. Because observations during extreme storms are often unavailable, a numerical model is used to simulate the storm-driven runup to compare to the parameterized model and then develop an approach to improve the accuracy of the parameterization. Numerically simulated and parameterized runup were compared to observations to evaluate model accuracies. The analysis demonstrated that setup was accurately predicted by both the parameterized model and numerical simulations. Infragravity swash heights were most accurately predicted by the parameterized model. The numerical model suffered from bias and gain errors that depended on whether a one-dimensional or two-dimensional spatial domain was used. Nonetheless, all of the predictions were significantly correlated to the observations, implying that the systematic errors can be corrected. The numerical simulations did not resolve the incident-band swash motions, as expected, and the parameterized model performed best at predicting incident-band swash heights. An assimilated prediction using a weighted average of the parameterized model and the numerical simulations resulted in a reduction in prediction error variance. Finally, the numerical simulations were extended to include storm conditions that have not been previously observed. These results indicated that the parameterized predictions of setup may need modification for extreme conditions; numerical simulations can be used to extend the validity of the parameterized predictions of infragravity swash; and numerical simulations systematically underpredict incident swash, which is relatively unimportant under extreme conditions.

  5. Numerical Modeling of Ophthalmic Response to Space

    Science.gov (United States)

    Nelson, E. S.; Myers, J. G.; Mulugeta, L.; Vera, J.; Raykin, J.; Feola, A.; Gleason, R.; Samuels, B.; Ethier, C. R.

    2015-01-01

    To investigate ophthalmic changes in spaceflight, we would like to predict the impact of blood dysregulation and elevated intracranial pressure (ICP) on Intraocular Pressure (IOP). Unlike other physiological systems, there are very few lumped parameter models of the eye. The eye model described here is novel in its inclusion of the human choroid and retrobulbar subarachnoid space (rSAS), which are key elements in investigating the impact of increased ICP and ocular blood volume. Some ingenuity was required in modeling the blood and rSAS compartments due to the lack of quantitative data on essential hydrodynamic quantities, such as net choroidal volume and blood flowrate, inlet and exit pressures, and material properties, such as compliances between compartments.

  6. Piecewise Polynomial Aggregation as Preprocessing for Data Numerical Modeling

    Science.gov (United States)

    Dobronets, B. S.; Popova, O. A.

    2018-05-01

    Data aggregation issues for numerical modeling are reviewed in the present study. The authors discuss data aggregation procedures as preprocessing for subsequent numerical modeling. To calculate the data aggregation, the authors propose using numerical probabilistic analysis (NPA). An important feature of this study is how the authors represent the aggregated data. The study shows that the offered approach to data aggregation can be interpreted as the frequency distribution of a variable. To study its properties, the density function is used. For this purpose, the authors propose using the piecewise polynomial models. A suitable example of such approach is the spline. The authors show that their approach to data aggregation allows reducing the level of data uncertainty and significantly increasing the efficiency of numerical calculations. To demonstrate the degree of the correspondence of the proposed methods to reality, the authors developed a theoretical framework and considered numerical examples devoted to time series aggregation.

  7. Numerical model updating technique for structures using firefly algorithm

    Science.gov (United States)

    Sai Kubair, K.; Mohan, S. C.

    2018-03-01

    Numerical model updating is a technique used for updating the existing experimental models for any structures related to civil, mechanical, automobiles, marine, aerospace engineering, etc. The basic concept behind this technique is updating the numerical models to closely match with experimental data obtained from real or prototype test structures. The present work involves the development of numerical model using MATLAB as a computational tool and with mathematical equations that define the experimental model. Firefly algorithm is used as an optimization tool in this study. In this updating process a response parameter of the structure has to be chosen, which helps to correlate the numerical model developed with the experimental results obtained. The variables for the updating can be either material or geometrical properties of the model or both. In this study, to verify the proposed technique, a cantilever beam is analyzed for its tip deflection and a space frame has been analyzed for its natural frequencies. Both the models are updated with their respective response values obtained from experimental results. The numerical results after updating show that there is a close relationship that can be brought between the experimental and the numerical models.

  8. Numerical Modeling of Rotary Kiln Productivity Increase

    NARCIS (Netherlands)

    Romero-Valle, M.A.; Pisaroni, M.; Van Puyvelde, D.; Lahaye, D.J.P.; Sadi, R.

    2013-01-01

    Rotary kilns are used in many industrial processes ranging from cement manufacturing to waste incineration. The operating conditions vary widely depending on the process. While there are many models available within the literature and industry, the wide range of operating conditions justifies

  9. Numerical modeling of transformer inrush currents

    Energy Technology Data Exchange (ETDEWEB)

    Cardelli, E. [Department of Industrial Engineering, University of Perugia, I-06125 Perugia (Italy); Center for Electric and Magnetic Applied Research (Italy); Faba, A., E-mail: faba@unipg.it [Department of Industrial Engineering, University of Perugia, I-06125 Perugia (Italy); Center for Electric and Magnetic Applied Research (Italy)

    2014-02-15

    This paper presents an application of a vector hysteresis model to the prediction of the inrush current due the arbitrary initial excitation of a transformer after a fault. The approach proposed seems promising in order to predict the transient overshoot in current and the optimal time to close the circuit after the fault.

  10. Numerical Modeling of Foam Drilling Hydraulics

    Directory of Open Access Journals (Sweden)

    Ozcan Baris

    2007-12-01

    Full Text Available The use of foam as a drilling fluid was developed to meet a special set of conditions under which other common drilling fluids had failed. Foam drilling is defined as the process of making boreholes by utilizing foam as the circulating fluid. When compared with conventional drilling, underbalanced or foam drilling has several advantages. These advantages include: avoidance of lost circulation problems, minimizing damage to pay zones, higher penetration rates and bit life. Foams are usually characterized by the quality, the ratio of the volume of gas, and the total foam volume. Obtaining dependable pressure profiles for aerated (gasified fluids and foam is more difficult than for single phase fluids, since in the former ones the drilling mud contains a gas phase that is entrained within the fluid system. The primary goal of this study is to expand the knowledge-base of the hydrodynamic phenomena that occur in a foam drilling operation. In order to gain a better understanding of foam drilling operations, a hydrodynamic model is developed and run at different operating conditions. For this purpose, the flow of foam through the drilling system is modeled by invoking the basic principles of continuum mechanics and thermodynamics. The model was designed to allow gas and liquid flow at desired volumetric flow rates through the drillstring and annulus. Parametric studies are conducted in order to identify the most influential variables in the hydrodynamic modeling of foam flow.

  11. Numerical Modelling and Prediction of Erosion Induced by Hydrodynamic Cavitation

    Science.gov (United States)

    Peters, A.; Lantermann, U.; el Moctar, O.

    2015-12-01

    The present work aims to predict cavitation erosion using a numerical flow solver together with a new developed erosion model. The erosion model is based on the hypothesis that collapses of single cavitation bubbles near solid boundaries form high velocity microjets, which cause sonic impacts with high pressure amplitudes damaging the surface. The erosion model uses information from a numerical Euler-Euler flow simulation to predict erosion sensitive areas and assess the erosion aggressiveness of the flow. The obtained numerical results were compared to experimental results from tests of an axisymmetric nozzle.

  12. Some Numerical Aspects on Crowd Motion - The Hughes Model

    KAUST Repository

    Gomes, Diogo A.

    2016-01-06

    Here, we study a crowd model proposed by R. Hughes in [5] and we describe a numerical approach to solve it. This model comprises a Fokker-Planck equation coupled with an Eikonal equation with Dirichlet or Neumann data. First, we establish a priori estimates for the solution. Second, we study radial solutions and identify a shock formation mechanism. Third, we illustrate the existence of congestion, the breakdown of the model, and the trend to the equilibrium. Finally, we propose a new numerical method and consider two numerical examples.

  13. Numerical Validation of Chemical Compositional Model for Wettability Alteration Processes

    Science.gov (United States)

    Bekbauov, Bakhbergen; Berdyshev, Abdumauvlen; Baishemirov, Zharasbek; Bau, Domenico

    2017-12-01

    Chemical compositional simulation of enhanced oil recovery and surfactant enhanced aquifer remediation processes is a complex task that involves solving dozens of equations for all grid blocks representing a reservoir. In the present work, we perform a numerical validation of the newly developed mathematical formulation which satisfies the conservation laws of mass and energy and allows applying a sequential solution approach to solve the governing equations separately and implicitly. Through its application to the numerical experiment using a wettability alteration model and comparisons with existing chemical compositional model's numerical results, the new model has proven to be practical, reliable and stable.

  14. Numerical Modelling and Measurement in a Test Secondary Settling Tank

    DEFF Research Database (Denmark)

    Dahl, C.; Larsen, Torben; Petersen, O.

    1994-01-01

    sludge. Phenomena as free and hindered settling and the Bingham plastic characteristic of activated sludge suspensions are included in the numerical model. Further characterisation and test tank experiments are described. The characterisation experiments were designed to measure calibration parameters...... for model description of settling and density differences. In the test tank experiments, flow velocities and suspended sludge concentrations were measured with different tank inlet geomotry and hydraulic and sludge loads. The test tank experiments provided results for the calibration of the numerical model......A numerical model and measurements of flow and settling in activated sludge suspension is presented. The numerical model is an attempt to describe the complex and interrelated hydraulic and sedimentation phenomena by describing the turbulent flow field and the transport/dispersion of suspended...

  15. Stochastic hydrogeologic units and hydrogeologic properties development for total-system performance assessments. Yucca Mountain Site Characterization Project

    International Nuclear Information System (INIS)

    Schenker, A.R.; Guerin, D.C.; Robey, T.H.; Rautman, C.A.; Barnard, R.W.

    1995-09-01

    A stochastic representation of the lithologic units and associated hydrogeologic parameters of the potential high-level nuclear waste repository are developed for use in performance-assessment calculations, including the Total-System Performance Assessment for Yucca Mountain-SNL Second Iteration (TSPA-1993). A simplified lithologic model has been developed based on the physical characteristics of the welded and nonwelded units at Yucca Mountain. Ten hydrogeologic units are developed from site-specific data (lithologic and geophysical logs and core photographs) obtained from the unsaturated and saturated zones. The three-dimensional geostatistical model of the ten hydrogeologic units is based on indicator-coding techniques and improves on the two-dimensional model developed for TSPA91. The hydrogeologic properties (statistics and probability distribution functions) are developed from the results of laboratory tests and in-situ aquifer tests or are derived through fundamental relationships. Hydrogeologic properties for matrix properties, bulk conductivities, and fractures are developed from existing site specific data. Extensive data are available for matrix porosity, bulk density, and matrix saturated conductivity. For other hydrogeologic properties, the data are minimal or nonexistent. Parameters for the properties are developed as beta probability distribution functions. For the model units without enough data for analysis, parameters are developed as analogs to existing units. A relational, analytic approach coupled with bulk conductivity parameters is used to develop fracture parameters based on the smooth-wall-parallel-plate theory. An analytic method is introduced for scaling small-core matrix properties to the hydrogeologic unit scales

  16. NUMERICAL MODELLING OF CHICKEN-FOOT FOUNDATION

    Directory of Open Access Journals (Sweden)

    Vipman Tandjiria

    1999-01-01

    Full Text Available This paper presents an analysis of the chicken-foot foundation using the finite element method. The foundation is considered as a reinforced concrete slab resting on a number of reinforced concrete pipes filled with and surrounded by in-situ soil. The soil and the pipes were modelled by isoparametric solid elements while the slab was modelled by isoparametric thick-plate elements. The study was intended to illustrate the basic mechanism of the chicken-foot foundation. Three cases have been considered for the parametric studies. The parameters investigated are thickness of slab, length of pipes and spacing between pipes. It is shown that such a foundation improves the behaviour of the raft foundation. It is also found that all the parameters used in the parametric studies influence the behaviour of the chicken-foot foundation.

  17. Analytical and numerical modeling for flexible pipes

    Science.gov (United States)

    Wang, Wei; Chen, Geng

    2011-12-01

    The unbonded flexible pipe of eight layers, in which all the layers except the carcass layer are assumed to have isotropic properties, has been analyzed. Specifically, the carcass layer shows the orthotropic characteristics. The effective elastic moduli of the carcass layer have been developed in terms of the influence of deformation to stiffness. With consideration of the effective elastic moduli, the structure can be properly analyzed. Also the relative movements of tendons and relative displacements of wires in helical armour layer have been investigated. A three-dimensional nonlinear finite element model has been presented to predict the response of flexible pipes under axial force and torque. Further, the friction and contact of interlayer have been considered. Comparison between the finite element model and experimental results obtained in literature has been given and discussed, which might provide practical and technical support for the application of unbonded flexible pipes.

  18. Numerical modeling of a vaporizing multicomponent droplet

    Science.gov (United States)

    Megaridis, C. M.; Sirignano, W. A.

    The fundamental processes governing the energy, mass, and momentum exchange between the liquid and gas phases of vaporizing, multicomponent liquid droplets have been investigated. The axisymmetric configuration under consideration consists of an isolated multicomponent droplet vaporizing in a convective environment. The model considers different volatilities of the liquid components, variable liquid properties due to variation of the species concentrations, and non-Fickian multicomponent gaseous diffusion. The bicomponent droplet model was employed to examine the commonly used assumptions of unity Lewis number in the liquid phase and Fickian gaseous diffusion. It is found that the droplet drag coefficients, the vaporization rates, and the related transfer numbers are not influenced by the above assumptions in a significant way.

  19. REPFLO model evaluation, physical and numerical consistency

    International Nuclear Information System (INIS)

    Wilson, R.N.; Holland, D.H.

    1978-11-01

    This report contains a description of some suggested changes and an evaluation of the REPFLO computer code, which models ground-water flow and nuclear-waste migration in and about a nuclear-waste repository. The discussion contained in the main body of the report is supplemented by a flow chart, presented in the Appendix of this report. The suggested changes are of four kinds: (1) technical changes to make the code compatible with a wider variety of digital computer systems; (2) changes to fill gaps in the computer code, due to missing proprietary subroutines; (3) changes to (a) correct programming errors, (b) correct logical flaws, and (c) remove unnecessary complexity; and (4) changes in the computer code logical structure to make REPFLO a more viable model from the physical point of view

  20. Numerical modeling of the debris flows runout

    Directory of Open Access Journals (Sweden)

    Federico Francesco

    2017-01-01

    Full Text Available Rapid debris flows are identified among the most dangerous of all landslides. Due to their destructive potential, the runout length has to be predicted to define the hazardous areas and design safeguarding measures. To this purpose, a continuum model to predict the debris flows mobility is developed. It is based on the well known depth-integrated avalanche model proposed by Savage and Hutter (S&H model to simulate the dry granular materials flows. Conservation of mass and momentum equations, describing the evolving geometry and the depth averaged velocity distribution, are re-written taking into account the effects of the interstitial pressures and the possible variation of mass along the motion due to erosion/deposition processes. Furthermore, the mechanical behaviour of the debris flow is described by a recently developed rheological law, which allows to take into account the dissipative effects of the grain inelastic collisions and friction, simultaneously acting within a ‘shear layer’, typically at the base of the debris flows. The governing PDEs are solved by applying the finite difference method. The analysis of a documented case is finally carried out.

  1. Numerical modelling of climate change impacts on freshwater lenses on the North Sea Island of Borkum

    Science.gov (United States)

    Sulzbacher, H.; Wiederhold, H.; Siemon, B.; Grinat, M.; Igel, J.; Burschil, T.; Günther, T.; Hinsby, K.

    2012-03-01

    A numerical variable-density groundwater model is set up for the North Sea Island of Borkum to estimate climate change impacts on coastal aquifers and especially the situation of barrier islands in the Wadden Sea. The database includes information from boreholes, a seismic survey, a helicopter-borne electromagnetic survey (HEM), monitoring of the freshwater-saltwater boundary by vertical electrode chains in two boreholes, measurements of groundwater table, pumping and slug tests, as well as water samples. Based on a statistical analysis of borehole columns, seismic sections and HEM, a hydrogeological model is set up. The groundwater model is developed using the finite-element programme FEFLOW. The variable-density groundwater model is calibrated on the basis of hydraulic, hydrological and geophysical data, in particular spatial HEM and local monitoring data. Verification runs with the calibrated model show good agreement between measured and computed hydraulic heads. A good agreement is also obtained between measured and computed density or total dissolved solids data for both the entire freshwater lens on a large scale and in the area of the well fields on a small scale. For simulating future changes in this coastal groundwater system until the end of the current century we use the climate scenario A2, specified by the Intergovernmental Panel on Climate Change and in particular the data for the German North Sea coast. Simulation runs show proceeding salinization with time beneath the well fields of the two waterworks Waterdelle and Ostland. The modelling study shows that spreading of well fields is an appropriate protection measure against excessive salinization of the water supply until the end of the current century.

  2. Complexities in coastal sediment transport studies by numerical modelling

    Digital Repository Service at National Institute of Oceanography (India)

    Ilangovan, D.; ManiMurali, R.

    equations arrived based on scientific principles as all natural phenomena are governed by certain rules which can be explained by scientific principles. Efficiency of numerical modeling greatly depends on quality of input parameters. When input parameters...

  3. Mathematical and numerical foundations of turbulence models and applications

    CERN Document Server

    Chacón Rebollo, Tomás

    2014-01-01

    With applications to climate, technology, and industry, the modeling and numerical simulation of turbulent flows are rich with history and modern relevance. The complexity of the problems that arise in the study of turbulence requires tools from various scientific disciplines, including mathematics, physics, engineering, and computer science. Authored by two experts in the area with a long history of collaboration, this monograph provides a current, detailed look at several turbulence models from both the theoretical and numerical perspectives. The k-epsilon, large-eddy simulation, and other models are rigorously derived and their performance is analyzed using benchmark simulations for real-world turbulent flows. Mathematical and Numerical Foundations of Turbulence Models and Applications is an ideal reference for students in applied mathematics and engineering, as well as researchers in mathematical and numerical fluid dynamics. It is also a valuable resource for advanced graduate students in fluid dynamics,...

  4. Summary of Numerical Modeling for Underground Nuclear Test Monitoring Symposium

    International Nuclear Information System (INIS)

    Taylor, S.R.; Kamm, J.R.

    1993-01-01

    This document contains the Proceedings of the Numerical Modeling for Underground Nuclear Test Monitoring Symposium held in Durango, Colorado on March 23-25, 1993. The symposium was sponsored by the Office of Arms Control and Nonproliferation of the United States Department of Energy and hosted by the Source Region Program of Los Alamos National Laboratory. The purpose of the meeting was to discuss state-of-the-art advances in numerical simulations of nuclear explosion phenomenology for the purpose of test ban monitoring. Another goal of the symposium was to promote discussion between seismologists and explosion source-code calculators. Presentation topics include the following: numerical model fits to data, measurement and characterization of material response models, applications of modeling to monitoring problems, explosion source phenomenology, numerical simulations and seismic sources

  5. Guadalupe River, California, Sedimentation Study. Numerical Model Investigation

    National Research Council Canada - National Science Library

    Copeland, Ronald

    2002-01-01

    A numerical model study was conducted to evaluate the potential impact that the Guadalupe River flood-control project would have on channel stability in terms of channel aggradation and degradation...

  6. Numerical Modeling of Subglacial Sediment Deformation

    DEFF Research Database (Denmark)

    Damsgaard, Anders

    2015-01-01

    may cause mass loss in the near future to exceed current best estimates. Ice flow in larger ice sheets focuses in fast-moving streams due to mechanical non-linearity of ice. These ice streams often move at velocities several magnitudes larger than surrounding ice and consequentially constitute...... glaciers move by deforming their sedimentary beds. Several modern ice streams, in particular, move as plug flows due to basal sediment deformation. An intense and long-winded discussion about the appropriate description for subglacial sediment mechanics followed this discovery, with good reason...... incompatible with commonly accepted till rheology models. Variation in pore-water pressure proves to cause reorganization in the internal stress network and leads to slow creeping deformation. The rate of creep is non-linearly dependent on the applied stresses. Granular creep can explain slow glacial...

  7. Reservoir Models for Gas Hydrate Numerical Simulation

    Science.gov (United States)

    Boswell, R.

    2016-12-01

    Scientific and industrial drilling programs have now providing detailed information on gas hydrate systems that will increasingly be the subject of field experiments. The need to carefully plan these programs requires reliable prediction of reservoir response to hydrate dissociation. Currently, a major emphasis in gas hydrate modeling is the integration of thermodynamic/hydrologic phenomena with geomechanical response for both reservoir and bounding strata. However, also critical to the ultimate success of these efforts is the appropriate development of input geologic models, including several emerging issues, including (1) reservoir heterogeneity, (2) understanding of the initial petrophysical characteristics of the system (reservoirs and seals), the dynamic evolution of those characteristics during active dissociation, and the interdependency of petrophysical parameters and (3) the nature of reservoir boundaries. Heterogeneity is ubiquitous aspect of every natural reservoir, and appropriate characterization is vital. However, heterogeneity is not random. Vertical variation can be evaluated with core and well log data; however, core data often are challenged by incomplete recovery. Well logs also provide interpretation challenges, particularly where reservoirs are thinly-bedded due to limitation in vertical resolution. This imprecision will extend to any petrophysical measurements that are derived from evaluation of log data. Extrapolation of log data laterally is also complex, and should be supported by geologic mapping. Key petrophysical parameters include porosity, permeability and it many aspects, and water saturation. Field data collected to date suggest that the degree of hydrate saturation is strongly controlled by/dependant upon reservoir quality and that the ratio of free to bound water in the remaining pore space is likely also controlled by reservoir quality. Further, those parameters will also evolve during dissociation, and not necessary in a simple

  8. Numerical modelling of the groundwater inflow to an advancing open pit mine: Kolahdarvazeh pit, Central Iran.

    Science.gov (United States)

    Bahrami, Saeed; Doulati Ardejani, Faramarz; Aslani, Soheyla; Baafi, Ernest

    2014-12-01

    The groundwater inflow into a mine during its life and after ceasing operations is one of the most important concerns of the mining industry. This paper presents a hydrogeological assessment of the Irankuh Zn-Pb mine at 20 km south of Esfahan and 1 km northeast of Abnil in west-Central Iran. During mine excavation, the upper impervious bed of a confined aquifer was broken and water at high-pressure flowed into an open pit mine associated with the Kolahdarvazeh deposit. The inflow rates were 6.7 and 1.4 m(3)/s at the maximum and minimum quantities, respectively. Permeability, storage coefficient, thickness and initial head of the fully saturated confined aquifer were 3.5 × 10(-4) m/s, 0.2, 30 m and 60 m, respectively. The hydraulic heads as a function of time were monitored at four observation wells in the vicinity of the pit over 19 weeks and at an observation well near a test well over 21 h. In addition, by measuring the rate of pumping out from the pit sump, at a constant head (usually equal to height of the pit floor), the real inflow rates to the pit were monitored. The main innovations of this work were to make comparison between numerical modelling using a finite element software called SEEP/W and actual data related to inflow and extend the applicability of the numerical model. This model was further used to estimate the hydraulic heads at the observation wells around the pit over 19 weeks during mining operations. Data from a pump-out test and observation wells were used for model calibration and verification. In order to evaluate the model efficiency, the modelling results of inflow quantity and hydraulic heads were compared to those from analytical solutions, as well as the field data. The mean percent error in relation to field data for the inflow quantity was 0.108. It varied between 1.16 and 1.46 for hydraulic head predictions, which are much lower values than the mean percent errors resulted from the analytical solutions (from 1.8 to 5

  9. Software verification, model validation, and hydrogeologic modelling aspects in nuclear waste disposal system simulations. A paradigm shift

    International Nuclear Information System (INIS)

    Sheng, G.M.

    1994-01-01

    This work reviewed the current concept of nuclear waste disposal in stable, terrestrial geologic media with a system of natural and man-made multi-barriers. Various aspects of this concept and supporting research were examined with the emphasis on the Canadian Nuclear Fuel Waste Management Program. Several of the crucial issues and challenges facing the current concept were discussed. These include: The difficulties inherent in a concept that centres around lithologic studies; the unsatisfactory state of software quality assurance in the present computer simulation programs; and the lack of a standardized, comprehensive, and systematic procedure to carry out a rigorous process of model validation and assessment of simulation studies. An outline of such an approach was presented and some of the principles, tools and techniques for software verification were introduced and described. A case study involving an evaluation of the Canadian performance assessment computer program is presented. A new paradigm to nuclear waste disposal was advocated to address the challenges facing the existing concept. The RRC (Regional Recharge Concept) was introduced and its many advantages were described and shown through a modelling exercise. (orig./HP)

  10. Hydrological and hydrogeological effects of an open repository in Forsmark. Final MIKE SHE flow modelling results for the Environmental Impact Assessment

    International Nuclear Information System (INIS)

    Maartensson, Erik; Gustafsson, Lars-Goeran

    2010-07-01

    This report presents methodology and modelling results concerning a deep-rock repository for spent nuclear fuel in Forsmark. Specifically, the modelling tools MIKE SHE, MIKE 11 and MOUSE are used to quantify the groundwater inflow to the repository and associated hydrological and hydrogeological effects during the construction and operation phases. The modelling results presented in the report provide input to the Environmental Impact Assessment (EIA) that will be part of a permit application according to the Environmental Code. Based on an existing MIKE SHE model for Forsmark, the first step of the modelling process was to implement an updated hydrogeological model of the bedrock and to increase the vertical and horizontal extents of the model domain. Other model updates involve the vegetation classification, and implementation of SFR (final repository for short-lived radioactive waste) and the subsurface drainage system at the nearby nuclear power plant. The updated model was calibrated using measured data on groundwater levels in the Quaternary deposits and the bedrock, water levels in lakes, and stream discharges. The calibrated model was then used for simulation of undisturbed conditions (i.e. without the repository) as a reference for modelling results obtained for disturbed conditions (with the repository). The modelling results for undisturbed conditions that are presented in the report closely resemble those of the final MIKE SHE site descriptive modelling (SDM-Site Forsmark). The repository layout was implemented as pipe links (segments) in the modelling tool MOUSE, and the implemented layout was used for the modelling of disturbed conditions. The study uses an updated and verified MIKE SHE-MOUSE coupling routine that is specifically adapted for calculation of groundwater inflow to grouted rock tunnels. The vertical shafts of the repository are implemented in the form of MIKE SHE grid cells with atmospheric pressure. Modelling results for disturbed

  11. Hydrological and hydrogeological effects of an open repository in Forsmark. Final MIKE SHE flow modelling results for the Environmental Impact Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Maartensson, Erik; Gustafsson, Lars-Goeran (DHI Sverige AB (Sweden))

    2010-07-15

    This report presents methodology and modelling results concerning a deep-rock repository for spent nuclear fuel in Forsmark. Specifically, the modelling tools MIKE SHE, MIKE 11 and MOUSE are used to quantify the groundwater inflow to the repository and associated hydrological and hydrogeological effects during the construction and operation phases. The modelling results presented in the report provide input to the Environmental Impact Assessment (EIA) that will be part of a permit application according to the Environmental Code. Based on an existing MIKE SHE model for Forsmark, the first step of the modelling process was to implement an updated hydrogeological model of the bedrock and to increase the vertical and horizontal extents of the model domain. Other model updates involve the vegetation classification, and implementation of SFR (final repository for short-lived radioactive waste) and the subsurface drainage system at the nearby nuclear power plant. The updated model was calibrated using measured data on groundwater levels in the Quaternary deposits and the bedrock, water levels in lakes, and stream discharges. The calibrated model was then used for simulation of undisturbed conditions (i.e. without the repository) as a reference for modelling results obtained for disturbed conditions (with the repository). The modelling results for undisturbed conditions that are presented in the report closely resemble those of the final MIKE SHE site descriptive modelling (SDM-Site Forsmark). The repository layout was implemented as pipe links (segments) in the modelling tool MOUSE, and the implemented layout was used for the modelling of disturbed conditions. The study uses an updated and verified MIKE SHE-MOUSE coupling routine that is specifically adapted for calculation of groundwater inflow to grouted rock tunnels. The vertical shafts of the repository are implemented in the form of MIKE SHE grid cells with atmospheric pressure. Modelling results for disturbed

  12. Numerical solution of dynamic equilibrium models under Poisson uncertainty

    DEFF Research Database (Denmark)

    Posch, Olaf; Trimborn, Timo

    2013-01-01

    We propose a simple and powerful numerical algorithm to compute the transition process in continuous-time dynamic equilibrium models with rare events. In this paper we transform the dynamic system of stochastic differential equations into a system of functional differential equations of the retar...... solution to Lucas' endogenous growth model under Poisson uncertainty are used to compute the exact numerical error. We show how (potential) catastrophic events such as rare natural disasters substantially affect the economic decisions of households....

  13. The Turbulent Interstellar Medium: Insights and Questions from Numerical Models

    OpenAIRE

    Mac Low, Mordecai-Mark; de Avillez, Miguel A.; Korpi, Maarit J.

    2003-01-01

    "The purpose of numerical models is not numbers but insight." (Hamming) In the spirit of this adage, and of Don Cox's approach to scientific speaking, we discuss the questions that the latest generation of numerical models of the interstellar medium raise, at least for us. The energy source for the interstellar turbulence is still under discussion. We review the argument for supernovae dominating in star forming regions. Magnetorotational instability has been suggested as a way of coupling di...

  14. Numerical modeling in photonic crystals integrated technology: the COPERNICUS Project

    DEFF Research Database (Denmark)

    Malaguti, Stefania; Armaroli, Andrea; Bellanca, Gaetano

    2011-01-01

    Photonic crystals will play a fundamental role in the future of optical communications. The relevance of the numerical modeling for the success of this technology is assessed by using some examples concerning the experience of the COPERNICUS Project.......Photonic crystals will play a fundamental role in the future of optical communications. The relevance of the numerical modeling for the success of this technology is assessed by using some examples concerning the experience of the COPERNICUS Project....

  15. Polynomial model inversion control: numerical tests and applications

    OpenAIRE

    Novara, Carlo

    2015-01-01

    A novel control design approach for general nonlinear systems is described in this paper. The approach is based on the identification of a polynomial model of the system to control and on the on-line inversion of this model. Extensive simulations are carried out to test the numerical efficiency of the approach. Numerical examples of applicative interest are presented, concerned with control of the Duffing oscillator, control of a robot manipulator and insulin regulation in a type 1 diabetic p...

  16. Numerical modelling of concentrated leak erosion during Hole Erosion Tests

    OpenAIRE

    Mercier, F.; Bonelli, S.; Golay, F.; Anselmet, F.; Philippe, P.; Borghi, R.

    2015-01-01

    This study focuses on the numerical modelling of concentrated leak erosion of a cohesive soil by a turbulent flow in axisymmetrical geometry, with application to the Hole Erosion Test (HET). The numerical model is based on adaptive remeshing of the water/soil interface to ensure accurate description of the mechanical phenomena occurring near the soil/water interface. The erosion law governing the interface motion is based on two erosion parameters: the critical shear stress and the erosion co...

  17. Soil remediation by heat injection: Experiments and numerical modelling

    Energy Technology Data Exchange (ETDEWEB)

    Betz, C.; Emmert, M.; Faerber, A. [Univ. of Stuttgart (Germany)] [and others

    1995-03-01

    In order to understand physical processes of thermally enhanced soil vapor extraction methods in porous media the isothermal, multiphase formulation for the numerical model MUFTE will be extended by a non-isothermal, multiphase-multicomponent formulation. In order to verify the numerical model, comparison with analytical solutions for well defined problems will be carried out. To identify relevant processes and their interactions, the results of the simulation will be compared with well controlled experiments with sophisticated measurement equipment in three different scales. The aim is to compare the different numerical solution techniques namely Finite Element versus Integral Finite Difference technique as implemented in MUFTE and TOUGH2 [9] respectively.

  18. Numerical approaches to expansion process modeling

    Directory of Open Access Journals (Sweden)

    G. V. Alekseev

    2017-01-01

    Full Text Available Forage production is currently undergoing a period of intensive renovation and introduction of the most advanced technologies and equipment. More and more often such methods as barley toasting, grain extrusion, steaming and grain flattening, boiling bed explosion, infrared ray treatment of cereals and legumes, followed by flattening, and one-time or two-time granulation of the purified whole grain without humidification in matrix presses By grinding the granules. These methods require special apparatuses, machines, auxiliary equipment, created on the basis of different methods of compiled mathematical models. When roasting, simulating the heat fields arising in the working chamber, provide such conditions, the decomposition of a portion of the starch to monosaccharides, which makes the grain sweetish, but due to protein denaturation the digestibility of the protein and the availability of amino acids decrease somewhat. Grain is roasted mainly for young animals in order to teach them to eat food at an early age, stimulate the secretory activity of digestion, better development of the masticatory muscles. In addition, the high temperature is detrimental to bacterial contamination and various types of fungi, which largely avoids possible diseases of the gastrointestinal tract. This method has found wide application directly on the farms. Apply when used in feeding animals and legumes: peas, soy, lupine and lentils. These feeds are preliminarily ground, and then cooked or steamed for 1 hour for 30–40 minutes. In the feed mill. Such processing of feeds allows inactivating the anti-nutrients in them, which reduce the effectiveness of their use. After processing, legumes are used as protein supplements in an amount of 25–30% of the total nutritional value of the diet. But it is recommended to cook and steal a grain of good quality. A poor-quality grain that has been stored for a long time and damaged by pathogenic micro flora is subject to

  19. Assessment of the Suitability of High Resolution Numerical Weather Model Outputs for Hydrological Modelling in Mountainous Cold Regions

    Science.gov (United States)

    Rasouli, K.; Pomeroy, J. W.; Hayashi, M.; Fang, X.; Gutmann, E. D.; Li, Y.

    2017-12-01

    The hydrology of mountainous cold regions has a large spatial variability that is driven both by climate variability and near-surface process variability associated with complex terrain and patterns of vegetation, soils, and hydrogeology. There is a need to downscale large-scale atmospheric circulations towards the fine scales that cold regions hydrological processes operate at to assess their spatial variability in complex terrain and quantify uncertainties by comparison to field observations. In this research, three high resolution numerical weather prediction models, namely, the Intermediate Complexity Atmosphere Research (ICAR), Weather Research and Forecasting (WRF), and Global Environmental Multiscale (GEM) models are used to represent spatial and temporal patterns of atmospheric conditions appropriate for hydrological modelling. An area covering high mountains and foothills of the Canadian Rockies was selected to assess and compare high resolution ICAR (1 km × 1 km), WRF (4 km × 4 km), and GEM (2.5 km × 2.5 km) model outputs with station-based meteorological measurements. ICAR with very low computational cost was run with different initial and boundary conditions and with finer spatial resolution, which allowed an assessment of modelling uncertainty and scaling that was difficult with WRF. Results show that ICAR, when compared with WRF and GEM, performs very well in precipitation and air temperature modelling in the Canadian Rockies, while all three models show a fair performance in simulating wind and humidity fields. Representation of local-scale atmospheric dynamics leading to realistic fields of temperature and precipitation by ICAR, WRF, and GEM makes these models suitable for high resolution cold regions hydrological predictions in complex terrain, which is a key factor in estimating water security in western Canada.

  20. A simple numerical model of a geometrically nonlinear Timoshenko beam

    NARCIS (Netherlands)

    Keijdener, C.; Metrikine, A.

    2015-01-01

    In the original problem for which this model was developed, onedimensional flexible objects interact through a non-linear contact model. Due to the non-linear nature of the contact model, a numerical time-domain approach was adopted. One of the goals was to see if the coupling between axial and

  1. A modular approach to numerical human body modeling

    NARCIS (Netherlands)

    Forbes, P.A.; Griotto, G.; Rooij, L. van

    2007-01-01

    The choice of a human body model for a simulated automotive impact scenario must take into account both accurate model response and computational efficiency as key factors. This study presents a "modular numerical human body modeling" approach which allows the creation of a customized human body

  2. Three-dimensional numerical modeling of the influence of faults on groundwater flow at Yucca Mountain, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, Andrew J.B. [Univ. of California, Berkeley, CA (United States)

    1999-06-01

    Numerical simulations of groundwater flow at Yucca Mountain, Nevada are used to investigate how the faulted hydrogeologic structure influences groundwater flow from a proposed high-level nuclear waste repository. Simulations are performed using a 3-D model that has a unique grid block discretization to accurately represent the faulted geologic units, which have variable thicknesses and orientations. Irregular grid blocks enable explicit representation of these features. Each hydrogeologic layer is discretized into a single layer of irregular and dipping grid blocks, and faults are discretized such that they are laterally continuous and displacement varies along strike. In addition, the presence of altered fault zones is explicitly modeled, as appropriate. The model has 23 layers and 11 faults, and approximately 57,000 grid blocks and 200,000 grid block connections. In the past, field measurement of upward vertical head gradients and high water table temperatures near faults were interpreted as indicators of upwelling from a deep carbonate aquifer. Simulations show, however, that these features can be readily explained by the geometry of hydrogeologic layers, the variability of layer permeabilities and thermal conductivities, and by the presence of permeable fault zones or faults with displacement only. In addition, a moderate water table gradient can result from fault displacement or a laterally continuous low permeability fault zone, but not from a high permeability fault zone, as others postulated earlier. Large-scale macrodispersion results from the vertical and lateral diversion of flow near the contact of high and low permeability layers at faults, and from upward flow within high permeability fault zones. Conversely, large-scale channeling can occur due to groundwater flow into areas with minimal fault displacement. Contaminants originating at the water table can flow in a direction significantly different than that of the water table gradient, and isolated

  3. Three-dimensional numerical modeling of the influence of faults on groundwater flow at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Cohen, Andrew J.B.

    1999-01-01

    Numerical simulations of groundwater flow at Yucca Mountain, Nevada are used to investigate how the faulted hydrogeologic structure influences groundwater flow from a proposed high-level nuclear waste repository. Simulations are performed using a 3-D model that has a unique grid block discretization to accurately represent the faulted geologic units, which have variable thicknesses and orientations. Irregular grid blocks enable explicit representation of these features. Each hydrogeologic layer is discretized into a single layer of irregular and dipping grid blocks, and faults are discretized such that they are laterally continuous and displacement varies along strike. In addition, the presence of altered fault zones is explicitly modeled, as appropriate. The model has 23 layers and 11 faults, and approximately 57,000 grid blocks and 200,000 grid block connections. In the past, field measurement of upward vertical head gradients and high water table temperatures near faults were interpreted as indicators of upwelling from a deep carbonate aquifer. Simulations show, however, that these features can be readily explained by the geometry of hydrogeologic layers, the variability of layer permeabilities and thermal conductivities, and by the presence of permeable fault zones or faults with displacement only. In addition, a moderate water table gradient can result from fault displacement or a laterally continuous low permeability fault zone, but not from a high permeability fault zone, as others postulated earlier. Large-scale macrodispersion results from the vertical and lateral diversion of flow near the contact of high and low permeability layers at faults, and from upward flow within high permeability fault zones. Conversely, large-scale channeling can occur due to groundwater flow into areas with minimal fault displacement. Contaminants originating at the water table can flow in a direction significantly different than that of the water table gradient, and isolated

  4. Hydraulic effects of unsealed boreholes. Numerical groundwater flow modelling of the Forsmark and Laxemar sites

    International Nuclear Information System (INIS)

    Bockgaard, Niclas

    2011-06-01

    The objective of the work was to investigate hydraulic effects of open and poorly sealed boreholes on groundwater flow conditions through simulations using a numerical groundwater model. Specifically, the boreholes KFM07A, KFM09A, and KFM09B in Forsmark and the boreholes KLX04, KLX06, and KLX10 in Laxemar were studied. The criteria for the selection of these boreholes were that the boreholes should represent typical conditions of the site, the borehole length should exceed 500 m, and that several major fractured zones should be intersected. The boreholes KFM07A and KLX06, respectively, were selected as reference boreholes for more detailed studies of different sealing schemes. The model setup of the Forsmark model followed the Forsmark 2.2 regional-scale conceptual hydrogeological model. The model domain was approximately 15 km (north-south) x 10 km (west- east) x 1.2 km (depth). The 131 deformation zones and three layers of superficial horizontal sheet joint were modelled deterministically. A stochastic discrete fracture network (DFN) representing fractures and minor deformation zones were also generated between the deterministic deformation zones inside central model volume. The side lengths of the square fractures were from 1,000 m down to 10 m. In order to resolve the details of flow in to and out from the borehole, a more detailed DFN was generated in a zone around the borehole KFM07A, where fractures down to a side length of 0.5 m were considered. The model setup of the Laxemar model followed the SDM-Site Laxemar (Laxemar 2.3) regional scale conceptual hydrogeological model. The model domain was approximately 12 km (north-south) x 20 km (west-east) x 2.1 km (depth). A number of 71 deformation zones were modelled deterministically, and one realization of a stochastic DFN, the so-called hydrogeological DFN model base case, was imported to the model. Similar to the Forsmark case, a more detailed DFN was also generated around the reference borehole KLX06. The

  5. Hydraulic effects of unsealed boreholes. Numerical groundwater flow modelling of the Forsmark and Laxemar sites

    Energy Technology Data Exchange (ETDEWEB)

    Bockgaard, Niclas [Golder Associates AB, Stockholm (Sweden)

    2011-06-15

    The objective of the work was to investigate hydraulic effects of open and poorly sealed boreholes on groundwater flow conditions through simulations using a numerical groundwater model. Specifically, the boreholes KFM07A, KFM09A, and KFM09B in Forsmark and the boreholes KLX04, KLX06, and KLX10 in Laxemar were studied. The criteria for the selection of these boreholes were that the boreholes should represent typical conditions of the site, the borehole length should exceed 500 m, and that several major fractured zones should be intersected. The boreholes KFM07A and KLX06, respectively, were selected as reference boreholes for more detailed studies of different sealing schemes. The model setup of the Forsmark model followed the Forsmark 2.2 regional-scale conceptual hydrogeological model. The model domain was approximately 15 km (north-south) x 10 km (west- east) x 1.2 km (depth). The 131 deformation zones and three layers of superficial horizontal sheet joint were modelled deterministically. A stochastic discrete fracture network (DFN) representing fractures and minor deformation zones were also generated between the deterministic deformation zones inside central model volume. The side lengths of the square fractures were from 1,000 m down to 10 m. In order to resolve the details of flow in to and out from the borehole, a more detailed DFN was generated in a zone around the borehole KFM07A, where fractures down to a side length of 0.5 m were considered. The model setup of the Laxemar model followed the SDM-Site Laxemar (Laxemar 2.3) regional scale conceptual hydrogeological model. The model domain was approximately 12 km (north-south) x 20 km (west-east) x 2.1 km (depth). A number of 71 deformation zones were modelled deterministically, and one realization of a stochastic DFN, the so-called hydrogeological DFN model base case, was imported to the model. Similar to the Forsmark case, a more detailed DFN was also generated around the reference borehole KLX06. The

  6. Numerical simulations of a reduced model for blood coagulation

    Science.gov (United States)

    Pavlova, Jevgenija; Fasano, Antonio; Sequeira, Adélia

    2016-04-01

    In this work, the three-dimensional numerical resolution of a complex mathematical model for the blood coagulation process is presented. The model was illustrated in Fasano et al. (Clin Hemorheol Microcirc 51:1-14, 2012), Pavlova et al. (Theor Biol 380:367-379, 2015). It incorporates the action of the biochemical and cellular components of blood as well as the effects of the flow. The model is characterized by a reduction in the biochemical network and considers the impact of the blood slip at the vessel wall. Numerical results showing the capacity of the model to predict different perturbations in the hemostatic system are discussed.

  7. Education and Employment in Hydrogeology.

    Science.gov (United States)

    Pederson, Darryll T.

    1987-01-01

    Reports on a study of position descriptions in the field of hydrogeology appearing in want ads, published studies describing the working professional, and published descriptions of hydrogeology programs. Results indicate an increase in positions of ten times that of five years ago. Suggests basic training requirements for beginning…

  8. Numerical Modeling and Mechanical Analysis of Flexible Risers

    Directory of Open Access Journals (Sweden)

    J. Y. Li

    2015-01-01

    Full Text Available ABAQUS is used to create a detailed finite element model for a 10-layer unbonded flexible riser to simulate the riser’s mechanical behavior under three load conditions: tension force and internal and external pressure. It presents a technique to create detailed finite element model and to analyze flexible risers. In FEM model, all layers are modeled separately with contact interfaces; interaction between steel trips in certain layers has been considered as well. FEM model considering contact interaction, geometric nonlinearity, and friction has been employed to accurately simulate the structural behavior of riser. The model includes the main features of the riser geometry with very little simplifying assumptions. The model was solved using a fully explicit time-integration scheme implemented in a parallel environment on an eight-processor cluster and 24 G memory computer. There is a very good agreement obtained from numerical and analytical comparisons, which validates the use of numerical model here. The results from the numerical simulation show that the numerical model takes into account various details of the riser. It has been shown that the detailed finite element model can be used to predict riser’s mechanics behavior under various load cases and bound conditions.

  9. Numerical modelling of river morphodynamics: Latest developments and remaining challenges

    Science.gov (United States)

    Siviglia, Annunziato; Crosato, Alessandra

    2016-07-01

    Numerical morphodynamic models provide scientific frameworks for advancing our understanding of river systems. The research on involved topics is an important and socially relevant undertaking regarding our environment. Nowadays numerical models are used for different purposes, from answering questions about basic morphodynamic research to managing complex river engineering problems. Due to increasing computer power and the development of advanced numerical techniques, morphodynamic models are now more and more used to predict the bed patterns evolution to a broad spectrum of spatial and temporal scales. The development and the success of application of such models are based upon a wide range of disciplines from applied mathematics for the numerical solution of the equations to geomorphology for the physical interpretation of the results. In this light we organized this special issue (SI) soliciting multidisciplinary contributions which encompass any aspect needed for the development and applications of such models. Most of the papers in the SI stem from contributions to session HS9.5/GM7.11 on numerical modelling and experiments in river morphodynamics at the European Geosciences Union (EGU) General Assembly held in Vienna, April 27th to May 2nd 2014.

  10. Nonspinning numerical relativity waveform surrogates: assessing the model

    Science.gov (United States)

    Field, Scott; Blackman, Jonathan; Galley, Chad; Scheel, Mark; Szilagyi, Bela; Tiglio, Manuel

    2015-04-01

    Recently, multi-modal gravitational waveform surrogate models have been built directly from data numerically generated by the Spectral Einstein Code (SpEC). I will describe ways in which the surrogate model error can be quantified. This task, in turn, requires (i) characterizing differences between waveforms computed by SpEC with those predicted by the surrogate model and (ii) estimating errors associated with the SpEC waveforms from which the surrogate is built. Both pieces can have numerous sources of numerical and systematic errors. We make an attempt to study the most dominant error sources and, ultimately, the surrogate model's fidelity. These investigations yield information about the surrogate model's uncertainty as a function of time (or frequency) and parameter, and could be useful in parameter estimation studies which seek to incorporate model error. Finally, I will conclude by comparing the numerical relativity surrogate model to other inspiral-merger-ringdown models. A companion talk will cover the building of multi-modal surrogate models.

  11. The transboundary non-renewable Nubian Aquifer System of Chad, Egypt, Libya and Sudan: classical groundwater questions and parsimonious hydrogeologic analysis and modeling

    Science.gov (United States)

    Voss, Clifford I.; Soliman, Safaa M.

    2014-03-01

    Parsimonious groundwater modeling provides insight into hydrogeologic functioning of the Nubian Aquifer System (NAS), the world's largest non-renewable groundwater system (belonging to Chad, Egypt, Libya, and Sudan). Classical groundwater-resource issues exist (magnitude and lateral extent of drawdown near pumping centers) with joint international management questions regarding transboundary drawdown. Much of NAS is thick, containing a large volume of high-quality groundwater, but receives insignificant recharge, so water-resource availability is time-limited. Informative aquifer data are lacking regarding large-scale response, providing only local-scale information near pumps. Proxy data provide primary underpinning for understanding regional response: Holocene water-table decline from the previous pluvial period, after thousands of years, results in current oasis/sabkha locations where the water table still intersects the ground. Depletion is found to be controlled by two regional parameters, hydraulic diffusivity and vertical anisotropy of permeability. Secondary data that provide insight are drawdowns near pumps and isotope-groundwater ages (million-year-old groundwaters in Egypt). The resultant strong simply structured three-dimensional model representation captures the essence of NAS regional groundwater-flow behavior. Model forecasts inform resource management that transboundary drawdown will likely be minimal—a nonissue—whereas drawdown within pumping centers may become excessive, requiring alternative extraction schemes; correspondingly, significant water-table drawdown may occur in pumping centers co-located with oases, causing oasis loss and environmental impacts.

  12. Thermodynamic analysis and numerical modeling of supercritical injection

    OpenAIRE

    Banuti, Daniel

    2015-01-01

    Although liquid propellant rocket engines are operational and have been studied for decades, cryogenic injection at supercritical pressures is still considered essentially not understood. This thesis intends to approach this problem in three steps: by developing a numerical model for real gas thermodynamics, by extending the present thermodynamic view of supercritical injection, and finally by applying these methods to the analysis of injection. A new numerical real gas thermodynamics mode...

  13. Numerical modeling of nitrogen oxide emission and experimental verification

    Directory of Open Access Journals (Sweden)

    Szecowka Lech

    2003-12-01

    Full Text Available The results of nitrogen reduction in combustion process with application of primary method are presented in paper. The reduction of NOx emission, by the recirculation of combustion gasses, staging of fuel and of air was investigated, and than the reduction of NOx emission by simultaneous usage of the mentioned above primary method with pulsatory disturbances.The investigations contain numerical modeling of NOx reduction and experimental verification of obtained numerical calculation results.

  14. Reservoir engineering and hydrogeology

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    Summaries are included which show advances in the following areas: fractured porous media, flow in single fractures or networks of fractures, hydrothermal flow, hydromechanical effects, hydrochemical processes, unsaturated-saturated systems, and multiphase multicomponent flows. The main thrust of these efforts is to understand the movement of mass and energy through rocks. This has involved treating fracture rock masses in which the flow phenomena within both the fractures and the matrix must be investigated. Studies also address the complex coupling between aspects of thermal, hydraulic, and mechanical processes associated with a nuclear waste repository in a fractured rock medium. In all these projects, both numerical modeling and simulation, as well as field studies, were employed. In the theoretical area, a basic understanding of multiphase flow, nonisothermal unsaturated behavior, and new numerical methods have been developed. The field work has involved reservoir testing, data analysis, and case histories at a number of geothermal projects

  15. Numerical modelling of the HAB Energy Buoy: Stage 1

    DEFF Research Database (Denmark)

    Kurniawan, Adi

    This report presents the results of the first stage of the project "Numerical modelling of the HAB Energy Buoy". The objectives of this stage are to develop a numerical model of the HAB Energy Buoy, a self-reacting wave energy device consisting of two heaving bodies, and to investigate a number...... and a summary of the main findings is presented. A numerical model of the HAB Energy Buoy has been developed in the frequency domain using two alternative formulations of the equations of motion. The model is capable of predicting the power capture, motion response, and power take-off loads of the device...... configuration are imposed to give a more realistic prediction of the power capture and help ensure a fair comparison. Recommendations with regard to the HAB design are finally suggested....

  16. Hydrogeological Study of Mangrove Areas Around Guanabara Bay, Rio de Janeiro, Brazil

    Directory of Open Access Journals (Sweden)

    Gerson Cardoso da Silva Júnior;

    2003-01-01

    Full Text Available The study area covers part of the mangrove belt located around Guanabara Bay, Rio de Janeiro, Brazil. Representing a continental-marine transition, the mangrove ecosystem is very susceptible to environmental variations and impacts. The vegetation cover plays an important role in prevention of erosion and contamination processes in those areas. An ongoing extensive research effort in the Petrochemical Complex of Duque de Caxias, Rio de Janeiro State, Brazil, focuses on the man-induced changes in the physical environment (soils, groundwater flow system, type and volumes of contaminants, geochemical aspects and the consequences on the neighboring mangrove ecosystem. This article describes the importance of hydrogeological studies in mangrove areas as part of an appropriate environmental assessment, taking as an example an industrial dumping area located in that Petrochemical Complex. Field work included extensive drilling and sampling to obtain basic geological and hydrogeological parameters and data in the pilot area, such as hydraulic conductivity and piezometric heads; emphasizing the tracking of possible contamination by industrial effluents and the marine influence; validation of the conceptual model with mathematical models (numerical and analytical models was carried out. Results show the great importance of well conducted and detailed hydrogeological studies to properly address environmental problems caused by industrial plants in mangrove areas.

  17. Numerical modelling of the jet nozzle enrichment process

    International Nuclear Information System (INIS)

    Vercelli, P.

    1983-01-01

    A numerical model was developed for the simulation of the isotopic enrichment produced by the jet nozzle process. The flow was considered stationary and under ideal gas conditions. The model calculates, for any position of the skimmer piece: (a) values of radial mass concentration profiles for each isotopic species and (b) values of elementary separation effect (Σ sub(A)) and uranium cut (theta). The comparison of the numerical results obtained with the experimental values given in the literature proves the validity of the present work as an initial step in the modelling of the process. (Author) [pt

  18. Generalized Roe's numerical scheme for a two-fluid model

    International Nuclear Information System (INIS)

    Toumi, I.; Raymond, P.

    1993-01-01

    This paper is devoted to a mathematical and numerical study of a six equation two-fluid model. We will prove that the model is strictly hyperbolic due to the inclusion of the virtual mass force term in the phasic momentum equations. The two-fluid model is naturally written under a nonconservative form. To solve the nonlinear Riemann problem for this nonconservative hyperbolic system, a generalized Roe's approximate Riemann solver, is used, based on a linearization of the nonconservative terms. A Godunov type numerical scheme is built, using this approximate Riemann solver. 10 refs., 5 figs,

  19. Numerical Modelling of Flow and Settling in Secondary Settling Tanks

    OpenAIRE

    Dahl, Claus Poulsen

    1995-01-01

    Denne afhandling omhandler udviklingen af en numerisk model til simulering af efterklaringstanke. lndledningsvis er beskrevet status for udviklingen inden for numeriske modeller for efterklaring og den nuværende designpraksis. Resultatet af denne statusbeskrivelse er et behov for videre udvikling for at indføre numeriske modeller i design af efterklaringstanke og hermed forbedre efterklaringstanke i fremtiden. This thesis discusses the development of a numerical model for the simulation of...

  20. Numerical equilibrium analysis for structured consumer resource models

    NARCIS (Netherlands)

    de Roos, A.M.; Diekmann, O.; Getto, P.; Kirkilionis, M.A.

    2010-01-01

    In this paper, we present methods for a numerical equilibrium and stability analysis for models of a size structured population competing for an unstructured re- source. We concentrate on cases where two model parameters are free, and thus existence boundaries for equilibria and stability boundaries

  1. Numerical equilibrium analysis for structured consumer resource models

    NARCIS (Netherlands)

    de Roos, A.M.; Diekmann, O.; Getto, P.; Kirkilionis, M.A.

    2010-01-01

    In this paper, we present methods for a numerical equilibrium and stability analysis for models of a size structured population competing for an unstructured resource. We concentrate on cases where two model parameters are free, and thus existence boundaries for equilibria and stability boundaries

  2. Application of numerical modelling in SSM automotive brake calliper castings

    CSIR Research Space (South Africa)

    Jahajeeah, N

    2006-01-01

    Full Text Available Numerical modelling has successfully been used as an efficient tool to convert a gravity cast brake calliper to a thixocasting process. The thixo-modue of Procast has been used for the modelling process to obtain optimum processing parameters...

  3. Some Numerical Aspects on Crowd Motion - The Hughes Model

    KAUST Repository

    Gomes, Diogo A.; Machado Velho, Roberto

    2016-01-01

    Here, we study a crowd model proposed by R. Hughes in [5] and we describe a numerical approach to solve it. This model comprises a Fokker-Planck equation coupled with an Eikonal equation with Dirichlet or Neumann data. First, we establish a priori

  4. Numerical human model for impact and seating comfort

    NARCIS (Netherlands)

    Hoof, J.F.A.M. van; Lange, R. de; Verver, M.M.

    2003-01-01

    This paper presents a detailed numerical model of the human body that can be used to evaluate both safety and comfort aspects of vehicle interiors. The model is based on a combination of rigid body and finite element techniques to provide an optimal combination of computational efficiency and

  5. Numerical modelling of erosion and sedimentation around offshore pipelines

    NARCIS (Netherlands)

    van Beek, F.A.; Wind, H.G.

    1990-01-01

    In this paper a numerical model is presented for the description of the erosion and sedimentation near pipelines on the sea bottom. The model is based on the Navier-Stokes equations and the equation of motion and continuity of sediment. The results of the simulations have been compared with the

  6. NUMERICAL PREDICTION MODELS FOR AIR POLLUTION BY MOTOR VEHICLE EMISSIONS

    Directory of Open Access Journals (Sweden)

    M. M. Biliaiev

    2016-12-01

    Full Text Available Purpose. Scientific work involves: 1 development of 3D numerical models that allow calculating the process of air pollution by motor vehicles emissions; 2 creation of models which would allow predicting the air pollution level in urban areas. Methodology. To solve the problem upon assessing the level of air pollution by motor vehicles emissions fundamental equations of aerodynamics and mass transfer are used. For the solution of differential equations of aerodynamics and mass transfer finite-difference methods are used. For the numerical integration of the equation for the velocity potential the method of conditional approximations is applied. The equation for the velocity potential written in differential form, splits into two equations, where at each step of splitting an unknown value of the velocity potential is determined by an explicit scheme of running computation, while the difference scheme is implicit one. For the numerical integration of the emissions dispersion equation in the atmosphere applies the implicit alternating-triangular difference scheme of splitting. Emissions from the road are modeled by a series of point sources of given intensity. Developed numerical models form is the basis of the created software package. Findings. 3D numerical models were developed; they belong to the class of «diagnostic models». These models take into account main physical factors that influence the process of dispersion of harmful substances in the atmosphere when emissions from vehicles in the city occur. Based on the constructed numerical models the computational experiment was conducted to assess the level of air pollution in the street. Originality. Authors have developed numerical models that allow to calculate the 3D aerodynamics of the wind flow in urban areas and the process of mass transfer emissions from the highway. Calculations to determine the area of contamination, which is formed near the buildings, located along the highway were

  7. Rapid installation of numerical models in multiple parent codes

    Energy Technology Data Exchange (ETDEWEB)

    Brannon, R.M.; Wong, M.K.

    1996-10-01

    A set of``model interface guidelines``, called MIG, is offered as a means to more rapidly install numerical models (such as stress-strain laws) into any parent code (hydrocode, finite element code, etc.) without having to modify the model subroutines. The model developer (who creates the model package in compliance with the guidelines) specifies the model`s input and storage requirements in a standardized way. For portability, database management (such as saving user inputs and field variables) is handled by the parent code. To date, NUG has proved viable in beta installations of several diverse models in vectorized and parallel codes written in different computer languages. A NUG-compliant model can be installed in different codes without modifying the model`s subroutines. By maintaining one model for many codes, MIG facilitates code-to-code comparisons and reduces duplication of effort potentially reducing the cost of installing and sharing models.

  8. Development of a numerical 2-dimensional beach evolution model

    DEFF Research Database (Denmark)

    Baykal, Cüneyt

    2014-01-01

    This paper presents the description of a 2-dimensional numerical model constructed for the simulation of beach evolution under the action of wind waves only over the arbitrary land and sea topographies around existing coastal structures and formations. The developed beach evolution numerical model...... is composed of 4 submodels: a nearshore spectral wave transformation model based on an energy balance equation including random wave breaking and diffraction terms to compute the nearshore wave characteristics, a nearshore wave-induced circulation model based on the nonlinear shallow water equations...... to compute the nearshore depth-averaged wave-induced current velocities and mean water level changes, a sediment transport model to compute the local total sediment transport rates occurring under the action of wind waves, and a bottom evolution model to compute the bed level changes in time based...

  9. The Liquid Film Flow with Evaporation: Numerical Modelling

    Directory of Open Access Journals (Sweden)

    Rezanova Ekaterina

    2016-01-01

    Full Text Available The flow of thin liquid layer on an inclined substrate is investigated numerically. The mathematical modelling is based on the Oberbeck-Boussinesq equations and the generalized conditions on the thermocapillary boundary simplified during the parametrical analysis. In the framework of the long-wave approximation the evolution equation which determines the thickness of the liquid layer in the case of moderate Reynolds numbers is derived. The results of numerical modelling of the liquid flow with evaporation at the interface are obtained.

  10. A numerical method for a transient two-fluid model

    International Nuclear Information System (INIS)

    Le Coq, G.; Libmann, M.

    1978-01-01

    The transient boiling two-phase flow is studied. In nuclear reactors, the driving conditions for the transient boiling are a pump power decay or/and an increase in heating power. The physical model adopted for the two-phase flow is the two fluid model with the assumption that the vapor remains at saturation. The numerical method for solving the thermohydraulics problems is a shooting method, this method is highly implicit. A particular problem exists at the boiling and condensation front. A computer code using this numerical method allow the calculation of a transient boiling initiated by a steady state for a PWR or for a LMFBR

  11. Calibration and verification of numerical runoff and erosion model

    Directory of Open Access Journals (Sweden)

    Gabrić Ognjen

    2015-01-01

    Full Text Available Based on the field and laboratory measurements, and analogous with development of computational techniques, runoff and erosion models based on equations which describe the physics of the process are also developed. Based on the KINEROS2 model, this paper presents basic modelling principles of runoff and erosion processes based on the St. Venant's equations. Alternative equations for friction calculation, calculation of source and deposition elements and transport capacity are also shown. Numerical models based on original and alternative equations are calibrated and verified on laboratory scale model. According to the results, friction calculation based on the analytic solution of laminar flow must be included in all runoff and erosion models.

  12. Urban hydrogeology in Indonesia: A highlight from Jakarta

    Science.gov (United States)

    Lubis, R. F.

    2018-02-01

    In many cities in the developing countries, groundwater is an important source of public water supply. The interaction between groundwater systems and urban environments has become an urgent challenge for many developing cities in the world, Indonesia included. Contributing factors are, but not limited to, the continuous horizontal and vertical expansion of cities, population growth, climate change, water scarcity and groundwater quality degradation. Jakarta as the capital city of Indonesia becomes a good example to study and implement urban hydrogeology. Urban hydrogeology is a science for investigating groundwater at the hydrological cycle and its change, water regime and quality within the urbanized landscape and zones of its impact. The present paper provides a review of urban groundwater studies in Jakarta in the context of urban water management, advances in hydrogeological investigation, monitoring and modelling since the city was established. The whole study emphasizes the necessity of an integrated urban groundwater management and development supporting hydrogeological techniques for urban areas.

  13. Numerical modelling of carbonate platforms and reefs: approaches and opportunities

    Energy Technology Data Exchange (ETDEWEB)

    Dalmasso, H.; Montaggioni, L.F.; Floquet, M. [Universite de Provence, Marseille (France). Centre de Sedimentologie-Palaeontologie; Bosence, D. [Royal Holloway University of London, Egham (United Kingdom). Dept. of Geology

    2001-07-01

    This paper compares different computing procedures that have been utilized in simulating shallow-water carbonate platform development. Based on our geological knowledge we can usually give a rather accurate qualitative description of the mechanisms controlling geological phenomena. Further description requires the use of computer stratigraphic simulation models that allow quantitative evaluation and understanding of the complex interactions of sedimentary depositional carbonate systems. The roles of modelling include: (1) encouraging accuracy and precision in data collection and process interpretation (Watney et al., 1999); (2) providing a means to quantitatively test interpretations concerning the control of various mechanisms on producing sedimentary packages; (3) predicting or extrapolating results into areas of limited control; (4) gaining new insights regarding the interaction of parameters; (5) helping focus on future studies to resolve specific problems. This paper addresses two main questions, namely: (1) What are the advantages and disadvantages of various types of models? (2) How well do models perform? In this paper we compare and discuss the application of five numerical models: CARBONATE (Bosence and Waltham, 1990), FUZZIM (Nordlund, 1999), CARBPLAT (Bosscher, 1992), DYNACARB (Li et al., 1993), PHIL (Bowman, 1997) and SEDPAK (Kendall et al., 1991). The comparison, testing and evaluation of these models allow one to gain a better knowledge and understanding of controlling parameters of carbonate platform development, which are necessary for modelling. Evaluating numerical models, critically comparing results from models using different approaches, and pushing experimental tests to their limits, provide an effective vehicle to improve and develop new numerical models. A main feature of this paper is to closely compare the performance between two numerical models: a forward model (CARBONATE) and a fuzzy logic model (FUZZIM). These two models use common

  14. Hydrogeology of northern Sierra de Chiapas, Mexico: a conceptual model based on a geochemical characterization of sulfide-rich karst brackish springs

    Science.gov (United States)

    Rosales Lagarde, Laura; Boston, Penelope J.; Campbell, Andrew R.; Hose, Louise D.; Axen, Gary; Stafford, Kevin W.

    2014-09-01

    Conspicuous sulfide-rich karst springs flow from Cretaceous carbonates in northern Sierra de Chiapas, Mexico. This is a geologically complex, tropical karst area. The physical, geologic, hydrologic and chemical attributes of these springs were determined and integrated into a conceptual hydrogeologic model. A meteoric source and a recharge elevation below 1,500 m are estimated from the spring-water isotopic signature regardless of their chemical composition. Brackish spring water flows at a maximum depth of 2,000 m, as inferred from similar chemical attributes to the produced water from a nearby oil well. Oil reservoirs may be found at depths below 2,000 m. Three subsurface environments or aquifers are identified based on the B, Li+, K+ and SiO2 concentrations, spring water temperatures, and CO2 pressures. There is mixing between these aquifers. The aquifer designated Local is shallow and contains potable water vulnerable to pollution. The aquifer named Northern receives some brackish produced water. The composition of the Southern aquifer is influenced by halite dissolution enhanced at fault detachment surfaces. Epigenic speleogenesis is associated with the Local springs. In contrast, hypogenic speleogenesis is associated with the brackish sulfidic springs from the Northern and the Southern environments.

  15. Mathematical modeling and numerical simulation of Czochralski Crystal Growth

    Energy Technology Data Exchange (ETDEWEB)

    Jaervinen, J.; Nieminen, R. [Center for Scientific Computing, Espoo (Finland)

    1996-12-31

    A detailed mathematical model and numerical simulation tools based on the SUPG Finite Element Method for the Czochralski crystal growth has been developed. In this presentation the mathematical modeling and numerical simulation of the melt flow and the temperature distribution in a rotationally symmetric crystal growth environment is investigated. The temperature distribution and the position of the free boundary between the solid and liquid phases are solved by using the Enthalpy method. Heat inside of the Czochralski furnace is transferred by radiation, conduction and convection. The melt flow is governed by the incompressible Navier-Stokes equations coupled with the enthalpy equation. The melt flow is numerically demonstrated and the temperature distribution in the whole Czochralski furnace. (author)

  16. Behavioral modeling of SRIM tables for numerical simulation

    Energy Technology Data Exchange (ETDEWEB)

    Martinie, S., E-mail: sebastien.martinie@cea.fr; Saad-Saoud, T.; Moindjie, S.; Munteanu, D.; Autran, J.L., E-mail: jean-luc.autran@univ-amu.fr

    2014-03-01

    Highlights: • Behavioral modeling of SRIM data is performed on the basis of power polynomial fitting functions. • Fast and continuous numerical functions are proposed for the stopping power and projected range. • Functions have been successfully tested for a wide variety of ions and targets. • Typical accuracies below the percent have been obtained in the range 1 keV–1 GeV. - Abstract: This work describes a simple way to implement SRIM stopping power and range tabulated data in the form of fast and continuous numerical functions for intensive simulation. We provide here the methodology of this behavioral modeling as well as the details of the implementation and some numerical examples for ions in silicon target. Developed functions have been successfully tested and used for the simulation of soft errors in microelectronics circuits.

  17. Mathematical modeling and numerical simulation of Czochralski Crystal Growth

    Energy Technology Data Exchange (ETDEWEB)

    Jaervinen, J; Nieminen, R [Center for Scientific Computing, Espoo (Finland)

    1997-12-31

    A detailed mathematical model and numerical simulation tools based on the SUPG Finite Element Method for the Czochralski crystal growth has been developed. In this presentation the mathematical modeling and numerical simulation of the melt flow and the temperature distribution in a rotationally symmetric crystal growth environment is investigated. The temperature distribution and the position of the free boundary between the solid and liquid phases are solved by using the Enthalpy method. Heat inside of the Czochralski furnace is transferred by radiation, conduction and convection. The melt flow is governed by the incompressible Navier-Stokes equations coupled with the enthalpy equation. The melt flow is numerically demonstrated and the temperature distribution in the whole Czochralski furnace. (author)

  18. Behavioral modeling of SRIM tables for numerical simulation

    International Nuclear Information System (INIS)

    Martinie, S.; Saad-Saoud, T.; Moindjie, S.; Munteanu, D.; Autran, J.L.

    2014-01-01

    Highlights: • Behavioral modeling of SRIM data is performed on the basis of power polynomial fitting functions. • Fast and continuous numerical functions are proposed for the stopping power and projected range. • Functions have been successfully tested for a wide variety of ions and targets. • Typical accuracies below the percent have been obtained in the range 1 keV–1 GeV. - Abstract: This work describes a simple way to implement SRIM stopping power and range tabulated data in the form of fast and continuous numerical functions for intensive simulation. We provide here the methodology of this behavioral modeling as well as the details of the implementation and some numerical examples for ions in silicon target. Developed functions have been successfully tested and used for the simulation of soft errors in microelectronics circuits

  19. Numerical modeling of turbulent combustion and flame spread

    Energy Technology Data Exchange (ETDEWEB)

    Yan Zhenghua

    1999-01-01

    Theoretical models have been developed to address several important aspects of numerical modeling of turbulent combustion and flame spread. The developed models include a pyrolysis model for charring and non-charring solid materials, a fast narrow band radiation property evaluation model (FASTNB) and a turbulence model for buoyant flow and flame. In the pyrolysis model, a completely new algorithm has been proposed, where a moving dual mesh concept was developed and implemented. With this new concept, it provides proper spatial resolution for both temperature and density and automatically considers the regression of the surface of the non-charring solid material during its pyrolysis. It is simple, very efficient and applicable to both charring and non-charring materials. FASTNB speeds up significantly the evaluation of narrow band spectral radiation properties and thus provides a potential of applying narrow band model in numerical simulations of practical turbulent combustion. The turbulence model was developed to improve the consideration of buoyancy effect on turbulence and turbulent transport. It was found to be simple, promising and numerically stable. It has been tested against both plane and axisymmetric thermal plumes and an axisymmetric buoyant diffusion flame. When compared with the widely used standard buoyancy-modified {kappa} - {epsilon} model, it gives significant improvement on numerical results. These developed models have been fully incorporated into CFD (Computational Fluid Dynamics) code and coupled with other CFD sub-models, including the DT (Discrete Transfer) radiation model, EDC (Eddy Dissipation Concept) combustion model, flamelet combustion model, various soot models and transpired wall function. Comprehensive numerical simulations have been carried out to study soot formation and oxidation in turbulent buoyant diffusion flames, flame heat transfer and flame spread in fires. The gas temperature and velocity, soot volume fraction, wall

  20. Assessing groundwater availability in a folded carbonate aquifer through the development of a numerical model

    Science.gov (United States)

    Di Salvo, Cristina; Romano, Emanuele; Guyennon, Nicolas; Bruna Petrangeli, Anna; Preziosi, Elisabetta

    2015-04-01

    The study of aquifer systems from a quantitative point of view is fundamental for adopting water management plans aiming at preserving water resources and reducing environmental risks related to groundwater level and discharge changes. This is also what the European Union Water Framework Directive (WFD, 2000/60/EC) states, holding the development of numerical models as a key aspect for groundwater management. The objective of this research is to i) define a methodology for modeling a complex hydrogeological structure in a structurally folded carbonate area and ii) estimate the concurrent effects of exploitation and climate changes on groundwater availability through the implementation of a 3D groundwater flow model. This study concerns the Monte Coscerno karst aquifer located in the Apennine chain in Central Italy in the Nera River Valley.This aquifer, is planned to be exploited in the near future for water supply. Negative trends of precipitation in Central Italy have been reported in relation to global climate changes, which are expected to affect the availability of recharge to carbonate aquifers throughout the region . A great concern is the combined impact of climate change and groundwater exploitation, hence scenarios are needed taking into account the effect of possible temperature and precipitation trends on recharge rates. Following a previous experience with model conceptualization and long-term simulation of groundwater flow, an integrated three-dimensional groundwater model has been developed for the Monte Coscerno aquifer. In a previous paper (Preziosi et al 2014) the spatial distribution of recharge to this aquifer was estimated through the Thornthwaite Mather model at a daily time step using as inputs past precipitation and temperature values (1951-2013) as well as soil and landscape properties. In this paper the numerical model development is described. On the basis of well logs from private consulting companies and literature cross sections the

  1. Physical and numerical modeling of Joule-heated melters

    Energy Technology Data Exchange (ETDEWEB)

    Eyler, L.L.; Skarda, R.J.; Crowder, R.S. III; Trent, D.S.; Reid, C.R.; Lessor, D.L.

    1985-10-01

    The Joule-heated ceramic-lined melter is an integral part of the high level waste immobilization process under development by the US Department of Energy. Scaleup and design of this waste glass melting furnace requires an understanding of the relationships between melting cavity design parameters and the furnace performance characteristics such as mixing, heat transfer, and electrical requirements. Developing empirical models of these relationships through actual melter testing with numerous designs would be a very costly and time consuming task. Additionally, the Pacific Northwest Laboratory (PNL) has been developing numerical models that simulate a Joule-heated melter for analyzing melter performance. This report documents the method used and results of this modeling effort. Numerical modeling results are compared with the more conventional, physical modeling results to validate the approach. Also included are the results of numerically simulating an operating research melter at PNL. Physical Joule-heated melters modeling results used for qualiying the simulation capabilities of the melter code included: (1) a melter with a single pair of electrodes and (2) a melter with a dual pair (two pairs) of electrodes. The physical model of the melter having two electrode pairs utilized a configuration with primary and secondary electrodes. The principal melter parameters (the ratio of power applied to each electrode pair, modeling fluid depth, electrode spacing) were varied in nine tests of the physical model during FY85. Code predictions were made for five of these tests. Voltage drops, temperature field data, and electric field data varied in their agreement with the physical modeling results, but in general were judged acceptable. 14 refs., 79 figs., 17 tabs.

  2. Physical and numerical modeling of Joule-heated melters

    International Nuclear Information System (INIS)

    Eyler, L.L.; Skarda, R.J.; Crowder, R.S. III; Trent, D.S.; Reid, C.R.; Lessor, D.L.

    1985-10-01

    The Joule-heated ceramic-lined melter is an integral part of the high level waste immobilization process under development by the US Department of Energy. Scaleup and design of this waste glass melting furnace requires an understanding of the relationships between melting cavity design parameters and the furnace performance characteristics such as mixing, heat transfer, and electrical requirements. Developing empirical models of these relationships through actual melter testing with numerous designs would be a very costly and time consuming task. Additionally, the Pacific Northwest Laboratory (PNL) has been developing numerical models that simulate a Joule-heated melter for analyzing melter performance. This report documents the method used and results of this modeling effort. Numerical modeling results are compared with the more conventional, physical modeling results to validate the approach. Also included are the results of numerically simulating an operating research melter at PNL. Physical Joule-heated melters modeling results used for qualiying the simulation capabilities of the melter code included: (1) a melter with a single pair of electrodes and (2) a melter with a dual pair (two pairs) of electrodes. The physical model of the melter having two electrode pairs utilized a configuration with primary and secondary electrodes. The principal melter parameters (the ratio of power applied to each electrode pair, modeling fluid depth, electrode spacing) were varied in nine tests of the physical model during FY85. Code predictions were made for five of these tests. Voltage drops, temperature field data, and electric field data varied in their agreement with the physical modeling results, but in general were judged acceptable. 14 refs., 79 figs., 17 tabs

  3. Numerical Simulation of the Heston Model under Stochastic Correlation

    Directory of Open Access Journals (Sweden)

    Long Teng

    2017-12-01

    Full Text Available Stochastic correlation models have become increasingly important in financial markets. In order to be able to price vanilla options in stochastic volatility and correlation models, in this work, we study the extension of the Heston model by imposing stochastic correlations driven by a stochastic differential equation. We discuss the efficient algorithms for the extended Heston model by incorporating stochastic correlations. Our numerical experiments show that the proposed algorithms can efficiently provide highly accurate results for the extended Heston by including stochastic correlations. By investigating the effect of stochastic correlations on the implied volatility, we find that the performance of the Heston model can be proved by including stochastic correlations.

  4. Numerical model for the thermal behavior of thermocline storage tanks

    Science.gov (United States)

    Ehtiwesh, Ismael A. S.; Sousa, Antonio C. M.

    2018-03-01

    Energy storage is a critical factor in the advancement of solar thermal power systems for the sustained delivery of electricity. In addition, the incorporation of thermal energy storage into the operation of concentrated solar power systems (CSPs) offers the potential of delivering electricity without fossil-fuel backup even during peak demand, independent of weather conditions and daylight. Despite this potential, some areas of the design and performance of thermocline systems still require further attention for future incorporation in commercial CSPs, particularly, their operation and control. Therefore, the present study aims to develop a simple but efficient numerical model to allow the comprehensive analysis of thermocline storage systems aiming better understanding of their dynamic temperature response. The validation results, despite the simplifying assumptions of the numerical model, agree well with the experiments for the time evolution of the thermocline region. Three different cases are considered to test the versatility of the numerical model; for the particular type of a storage tank with top round impingement inlet, a simple analytical model was developed to take into consideration the increased turbulence level in the mixing region. The numerical predictions for the three cases are in general good agreement against the experimental results.

  5. Bubbles in inkjet printheads: analytical and numerical models

    NARCIS (Netherlands)

    Jeurissen, R.J.M.

    2009-01-01

    The phenomenon of nozzle failure of an inkjet printhead due to entrainment of air bubbles was studies using analytical and numerical models. The studied inkjet printheads consist of many channels in which an acoustic field is generated to eject a droplet. When an air bubble is entrained, it disrupts

  6. Bubbles in inkjet printheads : analytical and numerical models

    NARCIS (Netherlands)

    Jeurissen, R.J.M.

    2009-01-01

    The phenomenon of nozzle failure of an inkjet printhead due to entrainment of air bubbles was studies using analytical and numerical models. The studied inkjet printheads consist of many channels in which an acoustic field is generated to eject a droplet. When an air bubble is entrained, it disrupts

  7. Numerical modeling of secondary side thermohydraulics of horizontal steam generator

    Energy Technology Data Exchange (ETDEWEB)

    Melikhov, V.I.; Melikhov, O.I.; Nigmatulin, B.I. [Research and Engineering Centre of LWR Nuclear Plants Safety, Moscow (Russian Federation)

    1995-12-31

    A mathematical model for the transient three-dimensional secondary side thermal hydraulics of the horizontal steam generator has been developed. The calculations of the steam generator PGV-1000 and PGV-4 nominal regimes and comparison of numerical and experimental results have been carried out. 7 refs.

  8. LED-based Photometric Stereo: Modeling, Calibration and Numerical Solutions

    DEFF Research Database (Denmark)

    Quéau, Yvain; Durix, Bastien; Wu, Tao

    2018-01-01

    We conduct a thorough study of photometric stereo under nearby point light source illumination, from modeling to numerical solution, through calibration. In the classical formulation of photometric stereo, the luminous fluxes are assumed to be directional, which is very difficult to achieve in pr...

  9. Numerical modeling of secondary side thermohydraulics of horizontal steam generator

    Energy Technology Data Exchange (ETDEWEB)

    Melikhov, V I; Melikhov, O I; Nigmatulin, B I [Research and Engineering Centre of LWR Nuclear Plants Safety, Moscow (Russian Federation)

    1996-12-31

    A mathematical model for the transient three-dimensional secondary side thermal hydraulics of the horizontal steam generator has been developed. The calculations of the steam generator PGV-1000 and PGV-4 nominal regimes and comparison of numerical and experimental results have been carried out. 7 refs.

  10. Physical and numerical modelling of low mach number compressible flows

    International Nuclear Information System (INIS)

    Paillerre, H.; Clerc, S.; Dabbene, F.; Cueto, O.

    1999-01-01

    This article reviews various physical models that may be used to describe compressible flow at low Mach numbers, as well as the numerical methods developed at DRN to discretize the different systems of equations. A selection of thermal-hydraulic applications illustrate the need to take into account compressibility and multidimensional effects as well as variable flow properties. (authors)

  11. Numerical Modeling of Multi-Material Active Magnetic Regeneration

    DEFF Research Database (Denmark)

    Nielsen, Kaspar Kirstein; Engelbrecht, Kurt; Bahl, Christian Robert Haffenden

    2009-01-01

    and the specific heat as a function of temperature at constant magnetic field. A 2.5-dimensional numerical model of an active magnetic regenerative (AMR) refrigerator device is presented. The experimental AMR located at Risø DTU has been equipped with a parallel-plate based regenerator made of the two materials...

  12. Numeral eddy current sensor modelling based on genetic neural network

    International Nuclear Information System (INIS)

    Yu Along

    2008-01-01

    This paper presents a method used to the numeral eddy current sensor modelling based on the genetic neural network to settle its nonlinear problem. The principle and algorithms of genetic neural network are introduced. In this method, the nonlinear model parameters of the numeral eddy current sensor are optimized by genetic neural network (GNN) according to measurement data. So the method remains both the global searching ability of genetic algorithm and the good local searching ability of neural network. The nonlinear model has the advantages of strong robustness, on-line modelling and high precision. The maximum nonlinearity error can be reduced to 0.037% by using GNN. However, the maximum nonlinearity error is 0.075% using the least square method

  13. Wind laws for shockless initialization. [numerical forecasting model

    Science.gov (United States)

    Ghil, M.; Shkoller, B.

    1976-01-01

    A system of diagnostic equations for the velocity field, or wind laws, was derived for each of a number of models of large-scale atmospheric flow. The derivation in each case is mathematically exact and does not involve any physical assumptions not already present in the prognostic equations, such as nondivergence or vanishing of derivatives of the divergence. Therefore, initial states computed by solving these diagnostic equations should be compatible with the type of motion described by the prognostic equations of the model and should not generate initialization shocks when inserted into the model. Numerical solutions of the diagnostic system corresponding to a barotropic model are exhibited. Some problems concerning the possibility of implementing such a system in operational numerical weather prediction are discussed.

  14. Numerical modeling of batch formation in waste incineration plants

    Directory of Open Access Journals (Sweden)

    Obroučka Karel

    2015-03-01

    Full Text Available The aim of this paper is a mathematical description of algorithm for controlled assembly of incinerated batch of waste. The basis for formation of batch is selected parameters of incinerated waste as its calorific value or content of pollutants or the combination of both. The numerical model will allow, based on selected criteria, to compile batch of wastes which continuously follows the previous batch, which is a prerequisite for optimized operation of incinerator. The model was prepared as for waste storage in containers, as well as for waste storage in continuously refilled boxes. The mathematical model was developed into the computer program and its functionality was verified either by practical measurements or by numerical simulations. The proposed model can be used in incinerators for hazardous and municipal waste.

  15. The Finite Element Numerical Modelling of 3D Magnetotelluric

    Directory of Open Access Journals (Sweden)

    Ligang Cao

    2014-01-01

    Full Text Available The ideal numerical simulation of 3D magnetotelluric was restricted by the methodology complexity and the time-consuming calculation. Boundary values, the variation of weighted residual equation, and the hexahedral mesh generation method of finite element are three major causes. A finite element method for 3D magnetotelluric numerical modeling is presented in this paper as a solution for the problem mentioned above. In this algorithm, a hexahedral element coefficient matrix for magnetoelluric finite method is developed, which solves large-scale equations using preconditioned conjugate gradient of the first-type boundary conditions. This algorithm is verified using the homogeneous model, and the positive landform model, as well as the low resistance anomaly model.

  16. Physical and numerical modelling of permafrost dynamic during a climatic cycle: implications for Meuse - Haute-Marne site

    International Nuclear Information System (INIS)

    Regnier, D.

    2012-01-01

    This manuscript deals about works realized on the permafrost modelling in porous media and its impact on the hydrogeological circulations. These are parts of the Andra's studies on the nuclear waste storage and, on the environmental studies of the Meuse/Haute-Marne (MHM) site. During a climatic cycle, cold periods can generate permafrost (ground with temperature lower than 0 C for 2 consecutive years). This peri-glacial structure propagates towards deep geological layers, and, due to its very low permeability, can stop the flow of water bodies like aquifers. This work presents the elaboration of two numerical models (with Cast3M code (CEA)): (i) a model with thermal conduction, used for the study of a cold wave propagation in porous media with phase transition (water-ice); (ii) a more complex model, managing the thermo-hydraulic coupling of ground phenomenon (conduction, convection and transition of phase). After validation, these two models offer three axes of development: (i) benchmark proposition by the study of two generic test-cases; (ii) study of the local air temperature signal on MHM site: importance of high frequency temperature variations (centennial scale) for permafrost depth and stability; (iii) study of the dynamics of a thermal discontinuity in a typical hydrological system river-plain: closure time of the system by the permafrost according to various parameters (temperatures, geothermal flow, hydrological flow directions). (author) [fr

  17. HYDROGEOLOGIC CASE STUDIES (DENVER PRESENTATION)

    Science.gov (United States)

    Hydrogeology is the foundation of subsurface site characterization for evaluations of monitored natural attenuation (MNA). Three case studies are presented. Examples of the potentially detrimental effects of drilling additives on ground-water samples from monitoring wells are d...

  18. HYDROGEOLOGIC CASE STUDIES (CHICAGO, IL)

    Science.gov (United States)

    Hydrogeology is the foundation of subsurface site characterization for evaluations of monitored natural attenuation (MNA). Three case studies are presented. Examples of the potentially detrimental effects of drilling additives on ground-water samples from monitoring wells are d...

  19. Hydrogeologic Case Studies (Seattle, WA)

    Science.gov (United States)

    Hydrogeology is the foundation of subsurface site characterization for evaluations of monitored natural attenuation (MNA). Three case studies are presented. Examples of the potentially detrimental effects of drilling additives on ground-water samples from monitoring wells are d...

  20. Numerical modelling of damage evolution in ingot forging

    DEFF Research Database (Denmark)

    Christiansen, Peter; Martins, Paulo A.F.; Bay, Niels Oluf

    2015-01-01

    The ingot forging process is numerically simulated applying both the Shima-Oyane porous plasticity model as a coupled damage model and the uncoupled normalized Cockcroft & Latham criterion. Four different cases including two different lower die angles (120º and 180º) and two different sizes of feed...... (400mm and 800mm) are analysed. Comparison of the simulation results with recommendations in literature on ingot forging, indicates the normalized Cockcroft & Latham damage criterion to be the most realistic of the two....

  1. Development of a geodatabase and conceptual model of the hydrogeologic units beneath air force plant 4 and Naval Air Station-Joint Reserve Base Carswell Field, Fort Worth, Texas

    Science.gov (United States)

    Shah, Sachin D.

    2004-01-01

    Air Force Plant 4 and adjacent Naval Air Station-Joint Reserve Base Carswell Field at Fort Worth, Texas, constitute a government-owned, contractor-operated facility that has been in operation since 1942. Contaminants from AFP4, primarily volatile organic compounds and metals, have entered the ground-water-flow system through leakage from waste-disposal sites and from manufacturing processes. The U.S. Geological Survey developed a comprehensive geodatabase of temporal and spatial environmental information associated with the hydrogeologic units (alluvial aquifer, Goodland-Walnut confining unit, and Paluxy aquifer) beneath the facility and a three-dimensional conceptual model of the hydrogeologic units integrally linked to the geodatabase. The geodatabase design uses a thematic layer approach to create layers of feature data using a geographic information system. The various features are separated into relational tables in the geodatabase on the basis of how they interact and correspond to one another. Using the geodatabase, geographic data at the site are manipulated to produce maps, allow interactive queries, and perform spatial analyses. The conceptual model for the study area comprises computer-generated, three-dimensional block diagrams of the hydrogeologic units. The conceptual model provides a platform for visualization of hydrogeologic-unit sections and surfaces and for subsurface environmental analyses. The conceptual model is based on three structural surfaces and two thickness configurations of the study area. The three structural surfaces depict the altitudes of the tops of the three hydrogeologic units. The two thickness configurations are those of the alluvial aquifer and the Goodland-Walnut confining unit. The surface of the alluvial aquifer was created using a U.S. Geological Survey 10-meter digital elevation model. The 2,130 point altitudes of the top of the Goodland-Walnut unit were compiled from lithologic logs from existing wells, available soil

  2. Numerical investigation of temperature distribution and thermal performance while charging-discharging thermal energy in aquifer

    NARCIS (Netherlands)

    Ganguly, S.; Mohan Kumar, M.S.; Date, Abhijit; Akbarzadeh, Aliakbar

    2017-01-01

    A three-dimensional (3D) coupled thermo-hydrogeological numerical model for a confined aquifer thermal energy storage (ATES) system underlain and overlain by rock media has been presented in this paper. The ATES system operates in cyclic mode. The model takes into account heat transport processes of

  3. Impact of hydrogeological factors on groundwater salinization due to ocean-surge inundation

    Science.gov (United States)

    Yang, Jie; Zhang, Huichen; Yu, Xuan; Graf, Thomas; Michael, Holly A.

    2018-01-01

    Ocean surges cause seawater inundation of coastal inland areas. Subsequently, seawater infiltrates into coastal aquifers and threatens the fresh groundwater resource. The severity of resulting salinization can be affected by hydrogeological factors including aquifer properties and hydrologic conditions, however, little research has been done to assess these effects. To understand the impacts of hydrogeological factors on groundwater salinization, we numerically simulated an ocean-surge inundation event on a two-dimensional conceptual coastal aquifer using a coupled surface-subsurface approach. We varied model permeability (including anisotropy), inland hydraulic gradient, and recharge rate. Three salinization-assessment indicators were developed, based on flushing time, depth of salt penetration, and a combination of the two, weighted flushing time, with which the impact of hydrogeological factors on groundwater vulnerability to salinization were quantitatively assessed. The vulnerability of coastal aquifers increases with increasing isotropic permeability. Low horizontal permeability (kx) and high vertical permeability (kz) lead to high aquifer vulnerability, and high kx and low kz lead to low aquifer vulnerability. Vulnerability decreases with increasing groundwater hydraulic gradient and increasing recharge rate. Additionally, coastal aquifers with a low recharge rate (R ≤ 300 mm yr-1) may be highly vulnerable to ocean-surge inundation. This study shows how the newly introduced indicators can be used to quantitatively assess coastal aquifer vulnerability. The results are important for global vulnerability assessment of coastal aquifers to ocean-surge inundation.

  4. Hydrogeologic subdivision of the Wolfcamp series and Pennsylvanian system of the Swisher Study Area, Texas: Revision 1: Topical report

    International Nuclear Information System (INIS)

    Siminitz, P.C.; Warman, E.A.

    1987-08-01

    The Pennsylvanian-Wolfcamp section in the Palo Duro Basin includes brine aquifers that are considered to be the most important ground- water flow paths in the deep-basin system. This report provides summary documentation of studies that subdivide the section into hydrogeologic units based on their judged relative capacities for transmitting water. This particular study area comprises eight counties in Texas, including Swisher County. Underground patterns of rock distribution are delineated from a hydrologic perspective and at a level of detail appropriate for numerical modeling of regional ground-water flow. Hydrogeologic units are defined and characterized so that appropriate porosity and permeability values can be assigned to each during construction of the numerical models and so that modelers can combine units where necessary. Hydrogeologic units have been defined as mappable, physically continuous rock bodies that function in bulk as water-transmitting or water-retarding units relative to adjacent rocks. Interpretations are made primarily from geophysical logs. Hydrologic characteristics are assessed on the basis of properties typically associated with certain lithologies (e.g., sandstones are more pervious than shales) and on the basis of gross variations in effective porosity (particularly in carbonate sequences). 15 refs., 52 figs., 1 tab

  5. Numerical modeling of oil spills in continental and estuarine waters

    International Nuclear Information System (INIS)

    Goeury, C.

    2012-10-01

    The application of the European Water Framework Directive on water quality for human consumption and industrial activities creates a need for water quality assessment and monitoring systems. The MIGR'HYCAR research project (http://www.migrhycar.com) was initiated to provide decisional tools for risks connected to oil spills in continental waters (rivers, lakes and estuaries), which represent more than 50% of accidental spills in France. Within the framework of this project, a new numerical oil spill model has been developed, as part of the TELEMAC hydro-informatics system (http://www.opentelemac.org), by combining Lagrangian and Eulerian methods. The Lagrangian model describes the transport of an oil spill near the free surface. The oil spill model enables to simulate the main processes driving oil plumes: advection, diffusion, oil beaching, oil re-floating, evaporation, dissolution, spreading and volatilization. Though generally considered as a minor process, dissolution is important from the point of view of toxicity. To model dissolved oil in water, an Eulerian advection-diffusion model is used. The fraction of dissolved oil is represented by a passive tracer. This approach is able to follow dissolved hydrocarbons in the water column. Laboratory experiments were conducted to characterise the numerous kinetics of the processes listed above. In addition, meso-scale dynamic experiments in artificial channels and test cases derived from the literature are used to validate the numerical model. (author)

  6. Drilling technologies in hydrogeological survey

    OpenAIRE

    Vorlíček, Petr

    2014-01-01

    This work deals with the drilling technologies used in hydrogeology. The main aim of the work is to explore types of drilling technologies used at hydrogeological drilling wells and modern technologies that could potentially be used in the future. The work also summarizes a historical development of drilling techniques, a drilling process procedure, information obtained from boreholes and the most common types of drilling fluids.

  7. Analysis and modeling of subgrid scalar mixing using numerical data

    Science.gov (United States)

    Girimaji, Sharath S.; Zhou, YE

    1995-01-01

    Direct numerical simulations (DNS) of passive scalar mixing in isotropic turbulence is used to study, analyze and, subsequently, model the role of small (subgrid) scales in the mixing process. In particular, we attempt to model the dissipation of the large scale (supergrid) scalar fluctuations caused by the subgrid scales by decomposing it into two parts: (1) the effect due to the interaction among the subgrid scales; and (2) the effect due to interaction between the supergrid and the subgrid scales. Model comparisons with DNS data show good agreement. This model is expected to be useful in the large eddy simulations of scalar mixing and reaction.

  8. Hartree-Fock-Bogoliubov model: a theoretical and numerical perspective

    International Nuclear Information System (INIS)

    Paul, S.

    2012-01-01

    This work is devoted to the theoretical and numerical study of Hartree-Fock-Bogoliubov (HFB) theory for attractive quantum systems, which is one of the main methods in nuclear physics. We first present the model and its main properties, and then explain how to get numerical solutions. We prove some convergence results, in particular for the simple fixed point algorithm (sometimes called Roothaan). We show that it converges, or oscillates between two states, none of them being a solution. This generalizes to the HFB case previous results of Cances and Le Bris for the simpler Hartree-Fock model in the repulsive case. Following these authors, we also propose a relaxed constraint algorithm for which convergence is guaranteed. In the last part of the thesis, we illustrate the behavior of these algorithms by some numerical experiments. We first consider a system where the particles only interact through the Newton potential. Our numerical results show that the pairing matrix never vanishes, a fact that has not yet been proved rigorously. We then study a very simplified model for protons and neutrons in a nucleus. (author)

  9. Numerical models for fluid-grains interactions: opportunities and limitations

    Science.gov (United States)

    Esteghamatian, Amir; Rahmani, Mona; Wachs, Anthony

    2017-06-01

    In the framework of a multi-scale approach, we develop numerical models for suspension flows. At the micro scale level, we perform particle-resolved numerical simulations using a Distributed Lagrange Multiplier/Fictitious Domain approach. At the meso scale level, we use a two-way Euler/Lagrange approach with a Gaussian filtering kernel to model fluid-solid momentum transfer. At both the micro and meso scale levels, particles are individually tracked in a Lagrangian way and all inter-particle collisions are computed by a Discrete Element/Soft-sphere method. The previous numerical models have been extended to handle particles of arbitrary shape (non-spherical, angular and even non-convex) as well as to treat heat and mass transfer. All simulation tools are fully-MPI parallel with standard domain decomposition and run on supercomputers with a satisfactory scalability on up to a few thousands of cores. The main asset of multi scale analysis is the ability to extend our comprehension of the dynamics of suspension flows based on the knowledge acquired from the high-fidelity micro scale simulations and to use that knowledge to improve the meso scale model. We illustrate how we can benefit from this strategy for a fluidized bed, where we introduce a stochastic drag force model derived from micro-scale simulations to recover the proper level of particle fluctuations. Conversely, we discuss the limitations of such modelling tools such as their limited ability to capture lubrication forces and boundary layers in highly inertial flows. We suggest ways to overcome these limitations in order to enhance further the capabilities of the numerical models.

  10. Numerical Analysis of Electromagnetic Fields in Multiscale Model

    International Nuclear Information System (INIS)

    Ma Ji; Fang Guang-You; Ji Yi-Cai

    2015-01-01

    Modeling technique for electromagnetic fields excited by antennas is an important topic in computational electromagnetics, which is concerned with the numerical solution of Maxwell's equations. In this paper, a novel hybrid technique that combines method of moments (MoM) with finite-difference time-domain (FDTD) method is presented to handle the problem. This approach employed Huygen's principle to realize the hybridization of the two classical numerical algorithms. For wideband electromagnetic data, the interpolation scheme is used in the MoM based on the dyadic Green's function. On the other hand, with the help of equivalence principle, the scattered electric and magnetic fields on the Huygen's surface calculated by MoM are taken as the sources for FDTD. Therefore, the electromagnetic fields in the environment can be obtained by employing finite-difference time-domain method. Finally, numerical results show the validity of the proposed technique by analyzing two canonical samples. (paper)

  11. Numerical modeling and experimental validation of thermoplastic composites induction welding

    Science.gov (United States)

    Palmieri, Barbara; Nele, Luigi; Galise, Francesco

    2018-05-01

    In this work, a numerical simulation and experimental test of the induction welding of continuous fibre-reinforced thermoplastic composites (CFRTPCs) was provided. The thermoplastic Polyamide 66 (PA66) with carbon fiber fabric was used. Using a dedicated software (JMag Designer), the influence of the fundamental process parameters such as temperature, current and holding time was investigated. In order to validate the results of the simulations, and therefore the numerical model used, experimental tests were carried out, and the temperature values measured during the tests were compared with the aid of an optical pyrometer, with those provided by the numerical simulation. The mechanical properties of the welded joints were evaluated by single lap shear tests.

  12. Direct numerical methods of mathematical modeling in mechanical structural design

    International Nuclear Information System (INIS)

    Sahili, Jihad; Verchery, Georges; Ghaddar, Ahmad; Zoaeter, Mohamed

    2002-01-01

    Full text.Structural design and numerical methods are generally interactive; requiring optimization procedures as the structure is analyzed. This analysis leads to define some mathematical terms, as the stiffness matrix, which are resulting from the modeling and then used in numerical techniques during the dimensioning procedure. These techniques and many others involve the calculation of the generalized inverse of the stiffness matrix, called also the 'compliance matrix'. The aim of this paper is to introduce first, some different existing mathematical procedures, used to calculate the compliance matrix from the stiffness matrix, then apply direct numerical methods to solve the obtained system with the lowest computational time, and to compare the obtained results. The results show a big difference of the computational time between the different procedures

  13. Overview--Development of a geodatabase and conceptual model of the hydrogeologic units beneath Air Force Plant 4 and Naval Air Station-Joint Reserve Base Carswell Field, Fort Worth, Texas

    Science.gov (United States)

    Shah, Sachin D.

    2004-01-01

    Air Force Plant 4 (AFP4) and adjacent Naval Air Station-Joint Reserve Base Carswell Field (NAS–JRB) at Fort Worth, Tex., constitute a contractor-owned, government-operated facility that has been in operation since 1942. Contaminants from the 3,600-acre facility, primarily volatile organic compounds (VOCs) and metals, have entered the ground-water-flow system through leakage from waste-disposal sites and from manufacturing processes. Environmental data collected at AFP4 and NAS–JRB during 1993–2002 created the need for consolidation of the data into a comprehensive temporal and spatial geodatabase. The U.S. Geological Survey (USGS), in cooperation with the U.S. Air Force Aeronautical Systems Center Environmental Management Directorate, developed a comprehensive geodatabase of temporal and spatial environmental data associated with the hydrogeologic units beneath the facility. A three-dimensional conceptual model of the hydrogeologic units integrally linked to the geodatabase was designed concurrently. Three hydrogeologic units—from land surface downward, the alluvial aquifer, the GoodlandWalnut confining unit, and the Paluxy aquifer—compose the subsurface of interest at AFP4 and NAS–JRB. The alluvial aquifer consists primarily of clay and silt with sand and gravel channel deposits that might be interconnected or interfingered. The Goodland-Walnut confining unit directly underlies the alluvial aquifer and consists of limestone, marl, shale, and clay. The Paluxy aquifer is composed of dense mudstone and fine- to coarse-grained sandstone

  14. Numerical modelling of flow and transport in rough fractures

    Directory of Open Access Journals (Sweden)

    Scott Briggs

    2014-12-01

    Full Text Available Simulation of flow and transport through rough walled rock fractures is investigated using the lattice Boltzmann method (LBM and random walk (RW, respectively. The numerical implementation is developed and validated on general purpose graphic processing units (GPGPUs. Both the LBM and RW method are well suited to parallel implementation on GPGPUs because they require only next-neighbour communication and thus can reduce expenses. The LBM model is an order of magnitude faster on GPGPUs than published results for LBM simulations run on modern CPUs. The fluid model is verified for parallel plate flow, backward facing step and single fracture flow; and the RW model is verified for point-source diffusion, Taylor-Aris dispersion and breakthrough behaviour in a single fracture. Both algorithms place limitations on the discrete displacement of fluid or particle transport per time step to minimise the numerical error that must be considered during implementation.

  15. Customer requirement modeling and mapping of numerical control machine

    Directory of Open Access Journals (Sweden)

    Zhongqi Sheng

    2015-10-01

    Full Text Available In order to better obtain information about customer requirement and develop products meeting customer requirement, it is necessary to systematically analyze and handle the customer requirement. This article uses the product service system of numerical control machine as research objective and studies the customer requirement modeling and mapping oriented toward configuration design. It introduces the conception of requirement unit, expounds the customer requirement decomposition rules, and establishes customer requirement model; it builds the house of quality using quality function deployment and confirms the weight of technical feature of product and service; it explores the relevance rules between data using rough set theory, establishes rule database, and solves the target value of technical feature of product. Using economical turning center series numerical control machine as an example, it verifies the rationality of proposed customer requirement model.

  16. Modern Perspectives on Numerical Modeling of Cardiac Pacemaker Cell

    Science.gov (United States)

    Maltsev, Victor A.; Yaniv, Yael; Maltsev, Anna V.; Stern, Michael D.; Lakatta, Edward G.

    2015-01-01

    Cardiac pacemaking is a complex phenomenon that is still not completely understood. Together with experimental studies, numerical modeling has been traditionally used to acquire mechanistic insights in this research area. This review summarizes the present state of numerical modeling of the cardiac pacemaker, including approaches to resolve present paradoxes and controversies. Specifically we discuss the requirement for realistic modeling to consider symmetrical importance of both intracellular and cell membrane processes (within a recent “coupled-clock” theory). Promising future developments of the complex pacemaker system models include the introduction of local calcium control, mitochondria function, and biochemical regulation of protein phosphorylation and cAMP production. Modern numerical and theoretical methods such as multi-parameter sensitivity analyses within extended populations of models and bifurcation analyses are also important for the definition of the most realistic parameters that describe a robust, yet simultaneously flexible operation of the coupled-clock pacemaker cell system. The systems approach to exploring cardiac pacemaker function will guide development of new therapies, such as biological pacemakers for treating insufficient cardiac pacemaker function that becomes especially prevalent with advancing age. PMID:24748434

  17. Numerical modeling of the 2017 active seismic infrasound balloon experiment

    Science.gov (United States)

    Brissaud, Q.; Komjathy, A.; Garcia, R.; Cutts, J. A.; Pauken, M.; Krishnamoorthy, S.; Mimoun, D.; Jackson, J. M.; Lai, V. H.; Kedar, S.; Levillain, E.

    2017-12-01

    We have developed a numerical tool to propagate acoustic and gravity waves in a coupled solid-fluid medium with topography. It is a hybrid method between a continuous Galerkin and a discontinuous Galerkin method that accounts for non-linear atmospheric waves, visco-elastic waves and topography. We apply this method to a recent experiment that took place in the Nevada desert to study acoustic waves from seismic events. This experiment, developed by JPL and its partners, wants to demonstrate the viability of a new approach to probe seismic-induced acoustic waves from a balloon platform. To the best of our knowledge, this could be the only way, for planetary missions, to perform tomography when one faces challenging surface conditions, with high pressure and temperature (e.g. Venus), and thus when it is impossible to use conventional electronics routinely employed on Earth. To fully demonstrate the effectiveness of such a technique one should also be able to reconstruct the observed signals from numerical modeling. To model the seismic hammer experiment and the subsequent acoustic wave propagation, we rely on a subsurface seismic model constructed from the seismometers measurements during the 2017 Nevada experiment and an atmospheric model built from meteorological data. The source is considered as a Gaussian point source located at the surface. Comparison between the numerical modeling and the experimental data could help future mission designs and provide great insights into the planet's interior structure.

  18. Hydrogeologic analysis of remedial alternatives for the solar ponds plume, RFETS

    International Nuclear Information System (INIS)

    McLane, C.F. III; Whidden, J.A.; Hopkins, J.K.

    1998-01-01

    The focus of this paper is to develop a conceptual model and a hydrogeologic analysis plan for remedial alternatives being considered for the remediation of a ground water contaminant plume consisting of chiefly nitrate and uranium. The initial step in this process was to determine the adequacy of the existing data from the vast database of site information. Upon concluding that the existing database was sufficient to allow for the development of a conceptual model and then constructing the conceptual model, a hydrogeologic analysis plan was developed to evaluate several alternatives for plume remediation. The plan will be implemented using a combination of analytical and simple numerical ground water flow and contaminant transport models. This allows each portion of the study to be addressed using the appropriate tool, without having to develop a large three-dimensional numerical ground water flow and transport model, thereby reducing project costs. The analysis plan will consist of a preliminary phase of screening analyses for each of the remedial alternative scenarios, and a second phase of more comprehensive and in-depth analyses on a selected subset of remedial alternative scenarios. One of the alternatives which will be analyzed is phytoremediation (remediation of soil and ground water via uptake of chemicals by plants) because of the potential for relatively low capital and operation and maintenance costs, passive nature, and potential to provide long-term protection of the surface water. The results of these hydrogeological analyses will be factored into the selection of the preferred remedial alternative, or combination of alternatives, for the contaminant plume

  19. A review of laboratory and numerical modelling in volcanology

    Directory of Open Access Journals (Sweden)

    J. L. Kavanagh

    2018-04-01

    Full Text Available Modelling has been used in the study of volcanic systems for more than 100 years, building upon the approach first applied by Sir James Hall in 1815. Informed by observations of volcanological phenomena in nature, including eye-witness accounts of eruptions, geophysical or geodetic monitoring of active volcanoes, and geological analysis of ancient deposits, laboratory and numerical models have been used to describe and quantify volcanic and magmatic processes that span orders of magnitudes of time and space. We review the use of laboratory and numerical modelling in volcanological research, focussing on sub-surface and eruptive processes including the accretion and evolution of magma chambers, the propagation of sheet intrusions, the development of volcanic flows (lava flows, pyroclastic density currents, and lahars, volcanic plume formation, and ash dispersal. When first introduced into volcanology, laboratory experiments and numerical simulations marked a transition in approach from broadly qualitative to increasingly quantitative research. These methods are now widely used in volcanology to describe the physical and chemical behaviours that govern volcanic and magmatic systems. Creating simplified models of highly dynamical systems enables volcanologists to simulate and potentially predict the nature and impact of future eruptions. These tools have provided significant insights into many aspects of the volcanic plumbing system and eruptive processes. The largest scientific advances in volcanology have come from a multidisciplinary approach, applying developments in diverse fields such as engineering and computer science to study magmatic and volcanic phenomena. A global effort in the integration of laboratory and numerical volcano modelling is now required to tackle key problems in volcanology and points towards the importance of benchmarking exercises and the need for protocols to be developed so that models are routinely tested against real

  20. A review of laboratory and numerical modelling in volcanology

    Science.gov (United States)

    Kavanagh, Janine L.; Engwell, Samantha L.; Martin, Simon A.

    2018-04-01

    Modelling has been used in the study of volcanic systems for more than 100 years, building upon the approach first applied by Sir James Hall in 1815. Informed by observations of volcanological phenomena in nature, including eye-witness accounts of eruptions, geophysical or geodetic monitoring of active volcanoes, and geological analysis of ancient deposits, laboratory and numerical models have been used to describe and quantify volcanic and magmatic processes that span orders of magnitudes of time and space. We review the use of laboratory and numerical modelling in volcanological research, focussing on sub-surface and eruptive processes including the accretion and evolution of magma chambers, the propagation of sheet intrusions, the development of volcanic flows (lava flows, pyroclastic density currents, and lahars), volcanic plume formation, and ash dispersal. When first introduced into volcanology, laboratory experiments and numerical simulations marked a transition in approach from broadly qualitative to increasingly quantitative research. These methods are now widely used in volcanology to describe the physical and chemical behaviours that govern volcanic and magmatic systems. Creating simplified models of highly dynamical systems enables volcanologists to simulate and potentially predict the nature and impact of future eruptions. These tools have provided significant insights into many aspects of the volcanic plumbing system and eruptive processes. The largest scientific advances in volcanology have come from a multidisciplinary approach, applying developments in diverse fields such as engineering and computer science to study magmatic and volcanic phenomena. A global effort in the integration of laboratory and numerical volcano modelling is now required to tackle key problems in volcanology and points towards the importance of benchmarking exercises and the need for protocols to be developed so that models are routinely tested against real world data.

  1. Modelization and numerical simulation of atmospheric aerosols dynamics

    International Nuclear Information System (INIS)

    Debry, Edouard

    2004-01-01

    Chemical-transport models are now able to describe in a realistic way gaseous pollutants behavior in the atmosphere. Nevertheless atmospheric pollution also exists as a fine suspended particles, called aerosols which interact with gaseous phase, solar radiation, and have their own dynamic behavior. The goal of this thesis is the modelization and numerical simulation of the General Dynamic Equation of aerosols (GDE). Part I deals with some theoretical aspects of aerosol modelization. Part II is dedicated to the building of one size resolved aerosol model (SIREAM). In part III we perform the reduction of this model in order to use it in dispersion models as POLAIR3D. Several modelization issues are still opened: organic aerosol matter, externally mixed aerosols, coupling with turbulent mixing, and nano-particles. (author) [fr

  2. Conceptual and numerical models of groundwater flow and solute transport in fracture zones: Application to the Aspo Island (Sweden)

    International Nuclear Information System (INIS)

    Molinero, J.; Samper, J.

    2003-01-01

    Several countries around the world are considering the final disposal of high-level radioactive waste in deep repositories located in fractured granite formations. Evaluating the long term safety of such repositories requires sound conceptual and numerical models which must consider simultaneously groundwater flow, solute transport and chemical and radiological processes. These models are being developed from data and knowledge gained from in situ experiments carried out at deep underground laboratories such as that of Aspo, Sweden, constructed in fractured granite. The Redox Zone Experiment is one of such experiments performed at Aspo in order to evaluate the effects of the construction of the access tunnel on the hydrogeological and hydrochemical conditions of a fracture zone intersected by the tunnel. Previous authors interpreted hydrochemical and isotopic data of this experiment using a mass-balance approach based on a qualitative description of groundwater flow conditions. Such an interpretation, however, is subject to uncertainties related to an over-simplified conceptualization of groundwater flow. Here we present numerical models of groundwater flow and solute transport for this fracture zone. The first model is based on previously published conceptual model. It presents noticeable un consistencies and fails to match simultaneously observed draw downs and chloride breakthrough curves. To overcome its limitations, a revised flow and transport model is presented which relies directly on available hydrodynamic and transport parameters, is based on the identification of appropriate flow and transport boundary conditions and uses, when needed, solute data extrapolated from nearby fracture zones. A significant quantitative improvement is achieved with the revised model because its results match simultaneously drawdown and chloride data. Other improvements are qualitative and include: ensuring consistency of hydrodynamic and hydrochemical data and avoiding

  3. Nirex 97 an assessment of the post-closure performance of a deep waste repository at Sellafield. Volume 1: hydrogeological model development - conceptual basis and data

    International Nuclear Information System (INIS)

    Degnan, P.; Littleboy, A.

    1997-01-01

    repository zone beneath Longlands Farm. In style, scope and presentation, Nirex 97 is primarily aimed at the scientific community, other radioactive waste disposal agencies and regulators. The report is published as part of Nirex's commitment to open publication of its scientific findings. The main value of the report currently is as a demonstration of the generic capability which has been developed to assess the radiological safety performance of candidate repository sites. The safety assessment reported as Nirex 97 was carried out between April 1996 and August 1997. It updates a preliminary assessment of the groundwater pathway for a repository at Sellafield, 'Nirex 95' published in July 1995. Nirex 97 takes account of further data obtained from the Nirex waste inventory, design, site characterisation and research programmes. In addition, Nirex 97 extends the Nirex 95 evaluation to include consideration of the potential radiological and flammability hazards in the biosphere arising from the effects of gas generation within the repository and the extent of pressurisation within the repository vaults. The assessment also takes account of the latest guidance from the Environment Agencies on requirements for authorisation of disposal facilities on land. Volume 1: Hydrogeological Conceptual Model Development - Conceptual Basis and Data, presents the conceptual model of the hydrogeology of the Sellafield area which underpins the post-closure performance assessment. The volume summarises the conceptual model development process and outlines the extensive site characterisation data for Sellafield which have been used in Nirex 97

  4. Physicochemical and numerical modeling of electrokinetics in inhomogenous matrices

    DEFF Research Database (Denmark)

    Paz-Garcia, Juan Manuel

    A physicochemical model has been proposed based on the Nernst-Planck-Poisson system. The model includes the transport of water through the porous media, the monitoring of the degree of saturation, the pH value and the porosity throughout the domain; and a comprehensive set of chemical and electrochemical reactions...... is mainly based on a finite elements method for the integration of the transient system of partial differential equations coupled with a Newton-Raphson method for computing chemical equilibrium. During the development of the proposed physicochemical and numerical model, different electrokinetic systems have...

  5. Numerical Modelling Of Humid Air Flow Around A Porous Body

    Directory of Open Access Journals (Sweden)

    Bohojło-Wiśniewska Aneta

    2015-09-01

    Full Text Available This paper presents an example of humid air flow around a single head of Chinese cabbage under conditions of complex heat transfer. This kind of numerical simulation allows us to create a heat and humidity transfer model between the Chinese cabbage and the flowing humid air. The calculations utilize the heat transfer model in porous medium, which includes the temperature difference between the solid (vegetable tissue and fluid (air phases of the porous medium. Modelling and calculations were performed in ANSYS Fluent 14.5 software.

  6. Numerical model of solar dynamic radiator for parametric analysis

    Science.gov (United States)

    Rhatigan, Jennifer L.

    1989-01-01

    Growth power requirements for Space Station Freedom will be met through addition of 25 kW solar dynamic (SD) power modules. Extensive thermal and power cycle modeling capabilities have been developed which are powerful tools in Station design and analysis, but which prove cumbersome and costly for simple component preliminary design studies. In order to aid in refining the SD radiator to the mature design stage, a simple and flexible numerical model was developed. The model simulates heat transfer and fluid flow performance of the radiator and calculates area mass and impact survivability for many combinations of flow tube and panel configurations, fluid and material properties, and environmental and cycle variations.

  7. Advanced modelling and numerical strategies in nuclear thermal-hydraulics

    International Nuclear Information System (INIS)

    Staedtke, H.

    2001-01-01

    The first part of the lecture gives a brief review of the current status of nuclear thermal hydraulics as it forms the basis of established system codes like TRAC, RELAP5, CATHARE or ATHLET. Specific emphasis is given to the capabilities and limitations of the underlying physical modelling and numerical solution strategies with regard to the description of complex transient two-phase flow and heat transfer conditions as expected to occur in PWR reactors during off-normal and accident conditions. The second part of the lecture focuses on new challenges and future needs in nuclear thermal-hydraulics which might arise with regard to re-licensing of old plants using bestestimate methodologies or the design and safety analysis of Advanced Light Water Reactors relying largely on passive safety systems. In order to meet these new requirements various advanced modelling and numerical techniques will be discussed including extended wellposed (hyperbolic) two-fluid models, explicit modelling of interfacial area transport or higher order numerical schemes allowing a high resolution of local multi-dimensional flow processes.(author)

  8. The concept of validation of numerical models for consequence analysis

    International Nuclear Information System (INIS)

    Borg, Audun; Paulsen Husted, Bjarne; Njå, Ove

    2014-01-01

    Numerical models such as computational fluid dynamics (CFD) models are increasingly used in life safety studies and other types of analyses to calculate the effects of fire and explosions. The validity of these models is usually established by benchmark testing. This is done to quantitatively measure the agreement between the predictions provided by the model and the real world represented by observations in experiments. This approach assumes that all variables in the real world relevant for the specific study are adequately measured in the experiments and in the predictions made by the model. In this paper the various definitions of validation for CFD models used for hazard prediction are investigated to assess their implication for consequence analysis in a design phase. In other words, how is uncertainty in the prediction of future events reflected in the validation process? The sources of uncertainty are viewed from the perspective of the safety engineer. An example of the use of a CFD model is included to illustrate the assumptions the analyst must make and how these affect the prediction made by the model. The assessments presented in this paper are based on a review of standards and best practice guides for CFD modeling and the documentation from two existing CFD programs. Our main thrust has been to assess how validation work is performed and communicated in practice. We conclude that the concept of validation adopted for numerical models is adequate in terms of model performance. However, it does not address the main sources of uncertainty from the perspective of the safety engineer. Uncertainty in the input quantities describing future events, which are determined by the model user, outweighs the inaccuracies in the model as reported in validation studies. - Highlights: • Examine the basic concept of validation applied to models for consequence analysis. • Review standards and guides for validation of numerical models. • Comparison of the validation

  9. Untangling Slab Dynamics Using 3-D Numerical and Analytical Models

    Science.gov (United States)

    Holt, A. F.; Royden, L.; Becker, T. W.

    2016-12-01

    Increasingly sophisticated numerical models have enabled us to make significant strides in identifying the key controls on how subducting slabs deform. For example, 3-D models have demonstrated that subducting plate width, and the related strength of toroidal flow around the plate edge, exerts a strong control on both the curvature and the rate of migration of the trench. However, the results of numerical subduction models can be difficult to interpret, and many first order dynamics issues remain at least partially unresolved. Such issues include the dominant controls on trench migration, the interdependence of asthenospheric pressure and slab dynamics, and how nearby slabs influence each other's dynamics. We augment 3-D, dynamically evolving finite element models with simple, analytical force-balance models to distill the physics associated with subduction into more manageable parts. We demonstrate that for single, isolated subducting slabs much of the complexity of our fully numerical models can be encapsulated by simple analytical expressions. Rates of subduction and slab dip correlate strongly with the asthenospheric pressure difference across the subducting slab. For double subduction, an additional slab gives rise to more complex mantle pressure and flow fields, and significantly extends the range of plate kinematics (e.g., convergence rate, trench migration rate) beyond those present in single slab models. Despite these additional complexities, we show that much of the dynamics of such multi-slab systems can be understood using the physics illuminated by our single slab study, and that a force-balance method can be used to relate intra-plate stress to viscous pressure in the asthenosphere and coupling forces at plate boundaries. This method has promise for rapid modeling of large systems of subduction zones on a global scale.

  10. Numerical Simulation of Hydrogen Combustion: Global Reaction Model and Validation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yun [School of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an (China); Department of Mechanical, Aerospace and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, NY (United States); Liu, Yinhe, E-mail: yinheliu@mail.xjtu.edu.cn [School of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an (China)

    2017-11-20

    Due to the complexity of modeling the combustion process in nuclear power plants, the global mechanisms are preferred for numerical simulation. To quickly perform the highly resolved simulations with limited processing resources of large-scale hydrogen combustion, a method based on thermal theory was developed to obtain kinetic parameters of global reaction mechanism of hydrogen–air combustion in a wide range. The calculated kinetic parameters at lower hydrogen concentration (C{sub hydrogen} < 20%) were validated against the results obtained from experimental measurements in a container and combustion test facility. In addition, the numerical data by the global mechanism (C{sub hydrogen} > 20%) were compared with the results by detailed mechanism. Good agreement between the model prediction and the experimental data was achieved, and the comparison between simulation results by the detailed mechanism and the global reaction mechanism show that the present calculated global mechanism has excellent predictable capabilities for a wide range of hydrogen–air mixtures.

  11. Elements of Constitutive Modelling and Numerical Analysis of Frictional Soils

    DEFF Research Database (Denmark)

    Jakobsen, Kim Parsberg

    of a constitutive model for soil is based on a profound knowledge of the soil behaviour upon loading. In the present study it is attempted to get a better understanding of the soil behaviour bv performing a number of triaxial compression tests on sand. The stress-strain behaviour of sand depends strongly......This thesis deals with elements of elasto-plastic constitutive modelling and numerical analysis of frictional soils. The thesis is based on a number of scientific papers and reports in which central characteristics of soil behaviour and applied numerical techniques are considered. The development...... and subsequently dilates during shear. The change in the volumetric behaviour of the soil skeleton is commonly referred to as the characteristic state. The stress ratio corresponding to the characteristic state is independent of the mean normal effective stress and the relative density, but depends on the stress...

  12. Mathematical and numerical modeling of early atherosclerotic lesions***

    Directory of Open Access Journals (Sweden)

    Raoult Annie

    2010-12-01

    Full Text Available This article is devoted to the construction of a mathematical model describing the early formation of atherosclerotic lesions. The early stage of atherosclerosis is an inflammatory process that starts with the penetration of low density lipoproteins in the intima and with their oxidation. This phenomenon is closely linked to the local blood flow dynamics. Extending a previous work [5] that was mainly restricted to a one-dimensional setting, we couple a simple lesion growth model relying on the biomolecular process that takes place in the intima with blood flow dynamics and mass transfer. We perform numerical simulations on a two-dimensional geometry taken from [6,7] that mimicks a carotid artery deformed by a perivascular cast and we compare the numerical results with experimental data.

  13. On numerical considerations for modeling reactive astrophysical shocks

    International Nuclear Information System (INIS)

    Papatheodore, Thomas L.; Messer, O. E. Bronson

    2014-01-01

    Simulating detonations in astrophysical environments is often complicated by numerical approximations to shock structure. A common prescription to ensure correct detonation speeds and associated quantities is to prohibit burning inside the numerically broadened shock. We have performed a series of simulations to verify the efficacy of this approximation and to understand how resolution and dimensionality might affect its use. Our results show that in one dimension, prohibiting burning in the shock is important wherever the carbon burning length is not resolved, in keeping with the results of Fryxell et al. In two dimensions, we find that the prohibition of shock burning effectively inhibits the development of cellular structure for all but the most highly resolved cases. We discuss the possible impacts this outcome may have on sub-grid models and detonation propagation in models of Type Ia supernovae, including potential impacts on observables.

  14. Numerical Simulation of Hydrogen Combustion: Global Reaction Model and Validation

    International Nuclear Information System (INIS)

    Zhang, Yun; Liu, Yinhe

    2017-01-01

    Due to the complexity of modeling the combustion process in nuclear power plants, the global mechanisms are preferred for numerical simulation. To quickly perform the highly resolved simulations with limited processing resources of large-scale hydrogen combustion, a method based on thermal theory was developed to obtain kinetic parameters of global reaction mechanism of hydrogen–air combustion in a wide range. The calculated kinetic parameters at lower hydrogen concentration (C hydrogen < 20%) were validated against the results obtained from experimental measurements in a container and combustion test facility. In addition, the numerical data by the global mechanism (C hydrogen > 20%) were compared with the results by detailed mechanism. Good agreement between the model prediction and the experimental data was achieved, and the comparison between simulation results by the detailed mechanism and the global reaction mechanism show that the present calculated global mechanism has excellent predictable capabilities for a wide range of hydrogen–air mixtures.

  15. Numerical modeling of a nuclear production reactor cooling lake

    International Nuclear Information System (INIS)

    Hamm, L.L.; Pepper, D.W.

    1987-01-01

    A finite element model has been developed which predicts flow and temperature distributions within a nuclear reactor cooling lake at the Savannah River Plant near Aiken, South Carolina. Numerical results agree with values obtained from a 3-D EPA numerical lake model and actual measurements obtained from the lake. Because the effluent water from the reactor heat exchangers discharges directly into the lake, downstream temperatures at mid-lake could exceed the South Carolina DHEC guidelines for thermal exchanges during the summer months. Therefore, reactor power was reduced to maintain temperature compliance at mid-lake. Thermal mitigation measures were studied that included placing a 6.1 m deep fabric curtain across mid-lake and moving the reactor outfall upstream. These measurements were calculated to permit about an 8% improvement in reactor power during summer operation

  16. OPTIMIZATION OF HEATING OF GEAR WHEEL USING NUMERICAL MODELING

    Directory of Open Access Journals (Sweden)

    Soňa Benešová

    2013-09-01

    Full Text Available Successful heat treating and carburizing of gear wheels for wind turbine gear boxes requires that plastic deformation in the wheel is minimized. Numerical modeling using the DEFORM software was aimed at exploring the effects of the base, on which the gear wheel rests during heating, on the heating process. Homogeneous heating was assumed. It was found that the base heats up more quickly than the workpiece. It is the consequence of the base's shape and volume. As a result, the base expands and slides against the wheel, predominantly at the first heating stage. Later on, it prevents the gear wheel from expanding, causing plastic deformation in the wheel. The findings were used for designing new heating schedules to minimize these undesirable interactions and to reduce the plastic deformation to a negligible magnitude. In addition, this paper presents an example of a practical use of numerical modeling in the DEFORM software.

  17. OPTIMIZATION OF HEATING OF GEAR WHEEL USING NUMERICAL MODELING

    Directory of Open Access Journals (Sweden)

    Sona Benesova

    2013-05-01

    Full Text Available Successful heat treating and carburizing of gear wheels for wind turbine gear boxes requires that plastic deformation in the wheel is minimized. Numerical modeling using the DEFORM software was aimed at exploring the effects of the base, on which the gear wheel rests during heating, on the heating process. Homogeneous heating was assumed. It was found that the base heats up more quickly than the workpiece. It is the consequence of the base's shape and volume. As a result, the base expands and slides against the wheel, predominantly at the first heating stage. Later on, it prevents the gear wheel from expanding, causing plastic deformation in the wheel. The findings were used for designing new heating schedules to minimize these undesirable interactions and to reduce the plastic deformation to a negligible magnitude. In addition, this paper presents an example of a practical use of numerical modeling in the DEFORM software.

  18. New Trends in Model Coupling Theory, Numerics and Applications

    International Nuclear Information System (INIS)

    Coquel, F.; Godlewski, E.; Herard, J. M.; Segre, J.

    2010-01-01

    This special issue comprises selected papers from the workshop New Trends in Model Coupling, Theory, Numerics and Applications (NTMC'09) which took place in Paris, September 2 - 4, 2009. The research of optimal technological solutions in a large amount of industrial systems requires to perform numerical simulations of complex phenomena which are often characterized by the coupling of models related to various space and/or time scales. Thus, the so-called multi-scale modelling has been a thriving scientific activity which connects applied mathematics and other disciplines such as physics, chemistry, biology or even social sciences. To illustrate the variety of fields concerned by the natural occurrence of model coupling we may quote: meteorology where it is required to take into account several turbulence scales or the interaction between oceans and atmosphere, but also regional models in a global description, solid mechanics where a thorough understanding of complex phenomena such as propagation of cracks needs to couple various models from the atomistic level to the macroscopic level; plasma physics for fusion energy for instance where dense plasmas and collisionless plasma coexist; multiphase fluid dynamics when several types of flow corresponding to several types of models are present simultaneously in complex circuits; social behaviour analysis with interaction between individual actions and collective behaviour. (authors)

  19. Condensation front modelling in a moisture separator reheater by application of SICLE numerical model

    International Nuclear Information System (INIS)

    Grange, J.L.; Caremoli, C.; Eddi, M.

    1988-01-01

    This paper presents improvements performed on SICLE numerical model in order to analyse the condensation front that occurs in the moisture separator reheaters (MSR) of nuclear power plants. Modifications of SICLE numerical model architecture and a fine modelling of reheater have allowed to correctly simulate the MSR thermohydraulic behaviour during a severe transient (plant islanding) [fr

  20. Numerical modeling of underground openings behavior with a viscoplastic approach

    International Nuclear Information System (INIS)

    Kleine, A.

    2007-01-01

    Nature is complex and must be approached in total modesty by engineers seeking to predict the behavior of underground openings. The engineering of industrial projects in underground situations, with high economic and social stakes (Alpine mountain crossings, nuclear waste repository), mean striving to gain better understanding of the behavioral mechanisms of the openings to be designed. This improvement necessarily involves better physical representativeness of macroscopic mechanisms and the provision of prediction tools suited to the expectations and needs of the engineers. The calculation tools developed in this work is in step with this concern for satisfying industrial needs and developing knowledge related to the rheology of geo-materials. These developments led to the proposing of a mechanical constitutive model, suited to lightly fissured rocks, comparable to continuous media, while integrating more particularly the effect of time. Thread of this study, the problematics ensued from the subject of the thesis is precisely about the rock mass delayed behavior in numerical modeling and its consequences on underground openings design. Based on physical concepts of reference, defined in several scales (macro/meso/micro), the developed constitutive model is translated in a mathematical formalism in order to be numerically implemented. Numerical applications presented as illustrations fall mainly within the framework of nuclear waste repository problems. They concern two very different configurations of underground openings: the AECL's underground canadian laboratory, excavated in the Lac du Bonnet granite, and the GMR gallery of Bure's laboratory (Meuse/Haute-Marne), dug in argillaceous rock. In this two cases, this constitutive model use highlights the gains to be obtained from allowing for delayed behavior regarding the accuracy of numerical tunnel behavior predictions in the short, medium and long terms. (author)

  1. NUMERICAL MODELING OF HARDENING OF UNINTERRUPTEDLY-CASTED BRONZE CASTING

    Directory of Open Access Journals (Sweden)

    E. I. Marukovich

    2009-01-01

    Full Text Available The three-dimensional numerical model for calculation of thermal fields during solidification of continuously casted bronze casting is developed. Coefficients of heat transfer on borders of calculation areas on the basis of the solution of inverse heat transfer conduction problem are determined. The analysis of thermal fields, depending on loop variables of drawing and the sizes of not cooled zone of crystallizer is curried out.

  2. Numerical modelling of so-called secondary ultrasonic echoes

    International Nuclear Information System (INIS)

    Langenberg, K.J.; Fellinger, P.; Hofmann, C.

    1994-01-01

    The formation of secondary ultrasonic echoes is discussed for a particularly simple testing situation. This discussion is based upon the intuitive visualization of elastic wave propagation as obtained with the numerical EFIT-Code (Elastodynamic Finite Integration Technique). The resulting travel times for the econdary echoes contain well-defined limits as they originate from the simple model of grazing incidence plane longitudinal wave mode conversion. (orig.) [de

  3. Numerical methods for modeling photonic-crystal VCSELs

    DEFF Research Database (Denmark)

    Dems, Maciej; Chung, Il-Sug; Nyakas, Peter

    2010-01-01

    We show comparison of four different numerical methods for simulating Photonic-Crystal (PC) VCSELs. We present the theoretical basis behind each method and analyze the differences by studying a benchmark VCSEL structure, where the PC structure penetrates all VCSEL layers, the entire top-mirror DBR...... to the effective index method. The simulation results elucidate the strength and weaknesses of the analyzed methods; and outline the limits of applicability of the different models....

  4. Numerical Modeling of a Wave Energy Point Absorber

    DEFF Research Database (Denmark)

    Hernandez, Lorenzo Banos; Frigaard, Peter; Kirkegaard, Poul Henning

    2009-01-01

    The present study deals with numerical modelling of the Wave Star Energy WSE device. Hereby, linear potential theory is applied via a BEM code on the wave hydrodynamics exciting the floaters. Time and frequency domain solutions of the floater response are determined for regular and irregular seas....... Furthermore, these results are used to estimate the power and the energy absorbed by a single oscillating floater. Finally, a latching control strategy is analysed in open-loop configuration for energy maximization....

  5. Modelling of multidimensional quantum systems by the numerical functional integration

    International Nuclear Information System (INIS)

    Lobanov, Yu.Yu.; Zhidkov, E.P.

    1990-01-01

    The employment of the numerical functional integration for the description of multidimensional systems in quantum and statistical physics is considered. For the multiple functional integrals with respect to Gaussian measures in the full separable metric spaces the new approximation formulas exact on a class of polynomial functionals of a given summary degree are constructed. The use of the formulas is demonstrated on example of computation of the Green function and the ground state energy in multidimensional Calogero model. 15 refs.; 2 tabs

  6. Hydrogeological conceptual model for Guarani Aquifer System: A tool for management; Modelo hidrogeologico conceptual del Sistema Acuifero Guarani (SAG): una herramienta para la gestion

    Energy Technology Data Exchange (ETDEWEB)

    Gastmans, D.; Veroslavsky, G.; Kiang Cahng, H.; Caetano-Chang, M. R.; Nogueira Pressinotti, M. M.

    2012-11-01

    The Guarani aquifer system (GAS) extends beneath the territories of Argentina, Brazil, Paraguay and Uruguay and thus represents a typical example of a transboundary aquifer. The GAS is an important source of drinking water for the population living within its area. Because of differences in the legal norms concerning water resources in these four countries, an urgently required legal framework for the shared management of the groundwater is currently being drawn up. Within this context, the conceptual regional hydrogeological model should be used as an important tool to delineate shared actions, particularly in regions where the groundwater flow is transboundary. The GAS is considered to be a continuous aquifer made up of Mesozoic continental clastic sedimentary rocks that occur in the Parana and Chacoparanense sedimentary basins, and is bounded at its base by a Permo-Eotriassic regional unconformity and at the top by lower-Cretaceous basaltic lava. The groundwater flow shows a regional trend from N to S along the main axis of these basins. With regard to the major tectonic structures of these sedimentary basins, various main hydrodynamic domains can be distinguished, such as the Ponta Grossa arch and the Asuncion-Rio Grande dorsal. Regional recharge areas are primarily located in the eastern and northern outcrop areas, whilst the western end of the GAS, the Mato Grosso do Sul, contains zones of local recharge and regional discharge. Transboundary flow is observed in areas confined to the national borders of the four countries. Nevertheless, due to the groundwater residence times in the GAS special management actions are called for to prevent over-exploitation, particularly in the confined zones of the aquifer. (Author)

  7. Numerical modeling of bubble dynamics in viscoelastic media with relaxation

    Science.gov (United States)

    Warnez, M. T.; Johnsen, E.

    2015-06-01

    Cavitation occurs in a variety of non-Newtonian fluids and viscoelastic materials. The large-amplitude volumetric oscillations of cavitation bubbles give rise to high temperatures and pressures at collapse, as well as induce large and rapid deformation of the surroundings. In this work, we develop a comprehensive numerical framework for spherical bubble dynamics in isotropic media obeying a wide range of viscoelastic constitutive relationships. Our numerical approach solves the compressible Keller-Miksis equation with full thermal effects (inside and outside the bubble) when coupled to a highly generalized constitutive relationship (which allows Newtonian, Kelvin-Voigt, Zener, linear Maxwell, upper-convected Maxwell, Jeffreys, Oldroyd-B, Giesekus, and Phan-Thien-Tanner models). For the latter two models, partial differential equations (PDEs) must be solved in the surrounding medium; for the remaining models, we show that the PDEs can be reduced to ordinary differential equations. To solve the general constitutive PDEs, we present a Chebyshev spectral collocation method, which is robust even for violent collapse. Combining this numerical approach with theoretical analysis, we simulate bubble dynamics in various viscoelastic media to determine the impact of relaxation time, a constitutive parameter, on the associated physics. Relaxation time is found to increase bubble growth and permit rebounds driven purely by residual stresses in the surroundings. Different regimes of oscillations occur depending on the relaxation time.

  8. Numerical equilibrium analysis for structured consumer resource models.

    Science.gov (United States)

    de Roos, A M; Diekmann, O; Getto, P; Kirkilionis, M A

    2010-02-01

    In this paper, we present methods for a numerical equilibrium and stability analysis for models of a size structured population competing for an unstructured resource. We concentrate on cases where two model parameters are free, and thus existence boundaries for equilibria and stability boundaries can be defined in the (two-parameter) plane. We numerically trace these implicitly defined curves using alternatingly tangent prediction and Newton correction. Evaluation of the maps defining the curves involves integration over individual size and individual survival probability (and their derivatives) as functions of individual age. Such ingredients are often defined as solutions of ODE, i.e., in general only implicitly. In our case, the right-hand sides of these ODE feature discontinuities that are caused by an abrupt change of behavior at the size where juveniles are assumed to turn adult. So, we combine the numerical solution of these ODE with curve tracing methods. We have implemented the algorithms for "Daphnia consuming algae" models in C-code. The results obtained by way of this implementation are shown in the form of graphs.

  9. Numerical solution of High-kappa model of superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Karamikhova, R. [Univ. of Texas, Arlington, TX (United States)

    1996-12-31

    We present formulation and finite element approximations of High-kappa model of superconductivity which is valid in the high {kappa}, high magnetic field setting and accounts for applied magnetic field and current. Major part of this work deals with steady-state and dynamic computational experiments which illustrate our theoretical results numerically. In our experiments we use Galerkin discretization in space along with Backward-Euler and Crank-Nicolson schemes in time. We show that for moderate values of {kappa}, steady states of the model system, computed using the High-kappa model, are virtually identical with results computed using the full Ginzburg-Landau (G-L) equations. We illustrate numerically optimal rates of convergence in space and time for the L{sup 2} and H{sup 1} norms of the error in the High-kappa solution. Finally, our numerical approximations demonstrate some well-known experimentally observed properties of high-temperature superconductors, such as appearance of vortices, effects of increasing the applied magnetic field and the sample size, and the effect of applied constant current.

  10. ASSIMILATION OF DOPPLER RADAR DATA INTO NUMERICAL WEATHER MODELS

    Energy Technology Data Exchange (ETDEWEB)

    Chiswell, S.; Buckley, R.

    2009-01-15

    During the year 2008, the United States National Weather Service (NWS) completed an eight fold increase in sampling capability for weather radars to 250 m resolution. This increase is expected to improve warning lead times by detecting small scale features sooner with increased reliability; however, current NWS operational model domains utilize grid spacing an order of magnitude larger than the radar data resolution, and therefore the added resolution of radar data is not fully exploited. The assimilation of radar reflectivity and velocity data into high resolution numerical weather model forecasts where grid spacing is comparable to the radar data resolution was investigated under a Laboratory Directed Research and Development (LDRD) 'quick hit' grant to determine the impact of improved data resolution on model predictions with specific initial proof of concept application to daily Savannah River Site operations and emergency response. Development of software to process NWS radar reflectivity and radial velocity data was undertaken for assimilation of observations into numerical models. Data values within the radar data volume undergo automated quality control (QC) analysis routines developed in support of this project to eliminate empty/missing data points, decrease anomalous propagation values, and determine error thresholds by utilizing the calculated variances among data values. The Weather Research and Forecasting model (WRF) three dimensional variational data assimilation package (WRF-3DVAR) was used to incorporate the QC'ed radar data into input and boundary conditions. The lack of observational data in the vicinity of SRS available to NWS operational models signifies an important data void where radar observations can provide significant input. These observations greatly enhance the knowledge of storm structures and the environmental conditions which influence their development. As the increase in computational power and availability has

  11. Numerical simulation of freshwater/seawater interaction in a dual-permeability karst system with conduits: the development of discrete-continuum VDFST-CFP model

    Science.gov (United States)

    Xu, Zexuan; Hu, Bill

    2016-04-01

    Dual-permeability karst aquifers of porous media and conduit networks with significant different hydrological characteristics are widely distributed in the world. Discrete-continuum numerical models, such as MODFLOW-CFP and CFPv2, have been verified as appropriate approaches to simulate groundwater flow and solute transport in numerical modeling of karst hydrogeology. On the other hand, seawater intrusion associated with fresh groundwater resources contamination has been observed and investigated in numbers of coastal aquifers, especially under conditions of sea level rise. Density-dependent numerical models including SEAWAT are able to quantitatively evaluate the seawater/freshwater interaction processes. A numerical model of variable-density flow and solute transport - conduit flow process (VDFST-CFP) is developed to provide a better description of seawater intrusion and submarine groundwater discharge in a coastal karst aquifer with conduits. The coupling discrete-continuum VDFST-CFP model applies Darcy-Weisbach equation to simulate non-laminar groundwater flow in the conduit system in which is conceptualized and discretized as pipes, while Darcy equation is still used in continuum porous media. Density-dependent groundwater flow and solute transport equations with appropriate density terms in both conduit and porous media systems are derived and numerically solved using standard finite difference method with an implicit iteration procedure. Synthetic horizontal and vertical benchmarks are created to validate the newly developed VDFST-CFP model by comparing with other numerical models such as variable density SEAWAT, couplings of constant density groundwater flow and solute transport MODFLOW/MT3DMS and discrete-continuum CFPv2/UMT3D models. VDFST-CFP model improves the simulation of density dependent seawater/freshwater mixing processes and exchanges between conduit and matrix. Continuum numerical models greatly overestimated the flow rate under turbulent flow

  12. Interaction of tide and salinity barrier: Limitation of numerical model

    Directory of Open Access Journals (Sweden)

    Suphat Vongvisessomjai1

    2008-07-01

    Full Text Available Nowadays, the study of interaction of the tide and the salinity barrier in an estuarine area is usually accomplished vianumerical modeling, due to the speed and convenience of modern computers. However, numerical models provide littleinsight with respect to the fundamental physical mechanisms involved. In this study, it is found that all existing numericalmodels work satisfactorily when the barrier is located at some distance far from upstream and downstream boundary conditions.Results are considerably underestimate reality when the barrier is located near the downstream boundary, usually theriver mouth. Meanwhile, this analytical model provides satisfactory output for all scenarios. The main problem of thenumerical model is that the effects of barrier construction in creation of reflected tide are neglected when specifying thedownstream boundary conditions; the use of the boundary condition before construction of the barrier which are significantlydifferent from those after the barrier construction would result in an error outputs. Future numerical models shouldattempt to account for this deficiency; otherwise, using this analytical model is another choice.

  13. Hydrogeological and Groundwater Flow Model for C, K, L, and P Reactor Areas, Savannah River Site, Aiken, South Carolina

    International Nuclear Information System (INIS)

    Flach, G.P.

    1999-01-01

    A regional groundwater flow model encompassing approximately 100 mi 2 surrounding the C, K. L. and P reactor areas has been developed. The Reactor flow model is designed to meet the planning objectives outlined in the General Groundwater Strategy for Reactor Area Projects by providing a common framework for analyzing groundwater flow, contaminant migration and remedial alternatives within the Reactor Projects team of the Environmental Restoration Department

  14. Hydrogeological and Groundwater Flow Model for C, K, L, and P Reactor Areas, Savannah River Site, Aiken, South Carolina

    Energy Technology Data Exchange (ETDEWEB)

    Flach, G.P.

    1999-02-24

    A regional groundwater flow model encompassing approximately 100 mi{sup 2} surrounding the C, K. L. and P reactor areas has been developed. The Reactor flow model is designed to meet the planning objectives outlined in the General Groundwater Strategy for Reactor Area Projects by providing a common framework for analyzing groundwater flow, contaminant migration and remedial alternatives within the Reactor Projects team of the Environmental Restoration Department.

  15. Numerical modeling of flow boiling instabilities using TRACE

    International Nuclear Information System (INIS)

    Kommer, Eric M.

    2015-01-01

    Highlights: • TRACE was used to realistically model boiling instabilities in single and parallel channel configurations. • Model parameters were chosen to exactly mimic other author’s work in order to provide for direct comparison of results. • Flow stability maps generated by the model show unstable flow at operating points similar to other authors. • The method of adjudicating when a flow is “unstable” is critical in this type of numerical study. - Abstract: Dynamic flow instabilities in two-phase systems are a vitally important area of study due to their effects on a great number of industrial applications, including heat exchangers in nuclear power plants. Several next generation nuclear reactor designs incorporate once through steam generators which will exhibit boiling flow instabilities if not properly designed or when operated outside design limits. A number of numerical thermal hydraulic codes attempt to model instabilities for initial design and for use in accident analysis. TRACE, the Nuclear Regulatory Commission’s newest thermal hydraulic code is used in this study to investigate flow instabilities in both single and dual parallel channel configurations. The model parameters are selected as to replicate other investigators’ experimental and numerical work in order to provide easy comparison. Particular attention is paid to the similarities between analysis using TRACE Version 5.0 and RELAP5/MOD3.3. Comparison of results is accomplished via flow stability maps non-dimensionalized via the phase change and subcooling numbers. Results of this study show that TRACE does indeed model two phase flow instabilities, with the transient response closely mimicking that seen in experimental studies. When compared to flow stability maps generated using RELAP, TRACE shows similar results with differences likely due to the somewhat qualitative criteria used by various authors to determine when the flow is truly unstable

  16. Numerical modeling of hypolimnetic oxygenation by electrolysis of water

    Directory of Open Access Journals (Sweden)

    Jaćimović Nenad M.

    2017-01-01

    Full Text Available The paper presents a novel method for hypolimnetic oxygenation by electrolysis of water. The performance of the method is investigated by the laboratory and the field experiment. The laboratory experiment is conducted in a 90 L vessel, while the field experiment is conducted at the lake Biwa in Japan. In order to provide a better insight into involved processes, a numerical model for simulation of bubble flow is developed with consideration of gas compressibility and oxygen dissolution. The model simultaneously solves 3-D volume averaged two-fluid governing equations. Developed model is firstly verified by simulation of bubble flow experiments, reported in the literature, where good qualitative agreement between measured and simulated results is observed. In the second part, the model is applied for simulation of conducted water electrolysis experiments. The model reproduced the observed oxygen concentration dynamics reasonably well. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 37009

  17. Numerical modeling of a cryogenic fluid within a fuel tank

    Science.gov (United States)

    Greer, Donald S.

    1994-01-01

    The computational method developed to study the cryogenic fluid characteristics inside a fuel tank in a hypersonic aircraft is presented. The model simulates a rapid draining of the tank by modeling the ullage vapor and the cryogenic liquid with a moving interface. A mathematical transformation was developed and applied to the Navier-Stokes equations to account for the moving interface. The formulation of the numerical method is a transient hybrid explicit-implicit technique where the pressure term in the momentum equations is approximated to first order in time by combining the continuity equation with an ideal equation of state.

  18. Comparison of the results of different scale hydrogeological models on a terraced slope of Valtellina (Northern Italy)

    Science.gov (United States)

    Camera, C.; Apuani, T.; Masetti, M.; Mele, M.

    2012-04-01

    The aim of this work was to understand and reproduce the hydrological dynamics of a slope that is terraced by dry-stone retaining walls. At first, the processes of interest were analyzed with a classical 2D unsaturated-saturated finite elements analysis, reproducing the geometry of a single terrace. In a second moment, a raster analysis at the slope scale was performed. The studied slope is located in Valtellina (Northern Italy), near the village of Tresenda, and in the last 30 years it experienced several soil slip/debris flow events that in 1983 caused 18 victims. Direct observation of the events of 1983 permitted to recognize the principal triggering cause of these events in the formation of an overpressure at the base of a dry-stone wall, that caused its failure. Using field tests and monitoring activity as input and calibration data respectively, the 2D model is able to explain the mechanisms of rainfall infiltration that can lead to the formation and evolution of a perched groundwater table at the contact between the bedrock and the walls backfill soil. Once calibrated and validated the model has been used to investigate the influence of different parameters on the studied processes, such as walls height, bedrock slope angle, and changes of both isotropic and anisotropic saturated hydraulic conductivity of soil and wall. From this sensitivity analysis, one of the most interesting results is the ability of the model to well differentiate the behaviour of a well maintained wall with an higher hydraulic conductivity than soil, from a poorly maintained wall that has lost part of its drainage capacity. In fact, only in this latter circumstance significant pore-water pressures can form at the base of the retaining structure. Moving the p