WorldWideScience

Sample records for undesired water flow

  1. Filtering Undesirable Flows in Networks

    NARCIS (Netherlands)

    Polevoy, G.; Trajanovski, S.; Grosso, P.; de Laat, C.; Gao, X.; Du, H.; Han, M.

    2017-01-01

    We study the problem of fully mitigating the effects of denial of service by filtering the minimum necessary set of the undesirable flows. First, we model this problem and then we concentrate on a subproblem where every good flow has a bottleneck. We prove that unless P=NP, this subproblem is

  2. Water Flow Experiments

    Indian Academy of Sciences (India)

    year undergraduate student at Ashoka University,. Sonipat, Haryana. This article studies how the height of water varies with time when water ... Experiment using a one-bottle system with a small bore tube at- tached to .... restricting free flow.

  3. Tube Length and Water Flow

    Directory of Open Access Journals (Sweden)

    Ben Ruktantichoke

    2011-06-01

    Full Text Available In this study water flowed through a straight horizontal plastic tube placed at the bottom of a large tank of water. The effect of changing the length of tubing on the velocity of flow was investigated. It was found that the Hagen-Poiseuille Equation is valid when the effect of water entering the tube is accounted for.

  4. Pressurized water reactor flow arrangement

    International Nuclear Information System (INIS)

    Gibbons, J.F.; Knapp, R.W.

    1980-01-01

    A flow path is provided for cooling the control rods of a pressurized water reactor. According to this scheme, a small amount of cooling water enters the control rod guide tubes from the top and passes downwards through the tubes before rejoining the main coolant flow and passing through the reactor core. (LL)

  5. Interventional radiology and undesirable effects

    International Nuclear Information System (INIS)

    Benderitter, M.

    2009-01-01

    As some procedures of interventional radiology are complex and long, doses received by patients can be high and cause undesired effects, notably on the skin or in underlying tissues (particularly in the brain as far as interventional neuroradiology is concerned and in lungs in the case of interventional cardiology). The author briefly discusses some deterministic effects in interventional radiology (influence of dose level, delay of appearance of effects, number of accidents). He briefly comments the diagnosis and treatment of severe radiological burns

  6. Simulation of gas compressible flow by free surface water flow

    International Nuclear Information System (INIS)

    Altafini, C.R.; Silva Ferreira, R.T. da

    1981-01-01

    The analogy between the water flow with a free surface and the compressible fluid flow, commonly called hydraulic analogy, is analyzed and its limitations are identified. The water table is the equipment used for this simulation, which allows the quatitative analysis of subsonic and supersonic flow with a low cost apparatus. The hydraulic analogy is applied to subsonic flow around circular cylinders and supersonic flow around cones. The results are compared with available theoretical and experimental data and a good agreement is achieved. (Author) [pt

  7. Morphometric methods for simulation of water flow

    NARCIS (Netherlands)

    Booltink, H.W.G.

    1993-01-01

    Water flow in structured soils is strongly governed by the occurence of macropores. In this study emphasis was given to combined research of morphology of water- conducting macropores and soil physical measurements on bypass flow. Main research objectives were to: (i) develop and improve

  8. Coupled equations for transient water flow, heat flow, and ...

    Indian Academy of Sciences (India)

    interacting processes, including flow of fluids, deformation of porous materials, chemical reactions, and transport of ... systems involving the flow of water, heat, and deformation. Such systems are ..... Defined thus, αI is independent of boundary con- ditions in an ... perature change with free deformation at constant total stress ...

  9. Measurement Of Multiphase Flow Water Fraction And Water-cut

    Science.gov (United States)

    Xie, Cheng-gang

    2007-06-01

    This paper describes a microwave transmission multiphase flow water-cut meter that measures the amplitude attenuation and phase shift across a pipe diameter at multiple frequencies using cavity-backed antennas. The multiphase flow mixture permittivity and conductivity are derived from a unified microwave transmission model for both water- and oil-continuous flows over a wide water-conductivity range; this is far beyond the capability of microwave-resonance-based sensors currently on the market. The water fraction and water cut are derived from a three-component gas-oil-water mixing model using the mixture permittivity or the mixture conductivity and an independently measured mixture density. Water salinity variations caused, for example, by changing formation water or formation/injection water breakthrough can be detected and corrected using an online water-conductivity tracking technique based on the interpretation of the mixture permittivity and conductivity, simultaneously measured by a single-modality microwave sensor.

  10. Endovascular rescue method for undesirably stretched coil.

    Science.gov (United States)

    Cho, Jae Hoon

    2014-10-01

    Undesirable detachment or stretching of coils within the parent artery during aneurysm embolization can be related with thrombus formation, which can be caused occlusion of parent artery or embolic event(s). To escape from this situation, several rescue methods have been reported. A case with undesirably stretched coil in which another rescue method was used, is presented. When the stretched coil is still located in the coil delivery microcatheter, the stretched coil can be removed safely using a snare and a handmade monorail microcatheter. After a snare is lodged in the handmade monorail microcatheter, the snare is introduced over the coil delivery micorcatheter and located in the distal part of the stretched coil. After then, the handmade monorail microcatheter captures the stretched coil and the snare as one unit. This technique using a handmade monorail microcatheter and a snare can be a good rescue modality for the undesirably stretched coil, still remained within the coil delivery microcatheter.

  11. Three Principles of Water Flow in Soils

    Science.gov (United States)

    Guo, L.; Lin, H.

    2016-12-01

    Knowledge of water flow in soils is crucial to understanding terrestrial hydrological cycle, surface energy balance, biogeochemical dynamics, ecosystem services, contaminant transport, and many other Critical Zone processes. However, due to the complex and dynamic nature of non-uniform flow, reconstruction and prediction of water flow in natural soils remain challenging. This study synthesizes three principles of water flow in soils that can improve modeling water flow in soils of various complexity. The first principle, known as the Darcy's law, came to light in the 19th century and suggested a linear relationship between water flux density and hydraulic gradient, which was modified by Buckingham for unsaturated soils. Combining mass balance and the Buckingham-Darcy's law, L.A. Richards quantitatively described soil water change with space and time, i.e., Richards equation. The second principle was proposed by L.A. Richards in the 20th century, which described the minimum pressure potential needed to overcome surface tension of fluid and initiate water flow through soil-air interface. This study extends this principle to encompass soil hydrologic phenomena related to varied interfaces and microscopic features and provides a more cohesive explanation of hysteresis, hydrophobicity, and threshold behavior when water moves through layered soils. The third principle is emerging in the 21st century, which highlights the complex and evolving flow networks embedded in heterogeneous soils. This principle is summarized as: Water moves non-uniformly in natural soils with a dual-flow regime, i.e., it follows the least-resistant or preferred paths when "pushed" (e.g., by storms) or "attracted" (e.g., by plants) or "restricted" (e.g., by bedrock), but moves diffusively into the matrix when "relaxed" (e.g., at rest) or "touched" (e.g., adsorption). The first principle is a macroscopic view of steady-state water flow, the second principle is a microscopic view of interface

  12. Risk sectors for undesirable behaviour and mobbing

    NARCIS (Netherlands)

    Hubert, A.B.; Veldhoven, M.J.P.M. van

    2001-01-01

    The aim of this short note was to get an impression of risk sectors for the prevalence of undesirable behaviour and mobbing in The Netherlands. Data were collected from 1995 to 1999 with the Questionnaire on The Assessment and Experience of Work (Vragenlijst Beleving en Beoordeling van de Arbeid;

  13. Water flow at all scales

    DEFF Research Database (Denmark)

    Sand-Jensen, K.

    2006-01-01

    Continuous water fl ow is a unique feature of streams and distinguishes them from all other ecosystems. The main fl ow is always downstream but it varies in time and space and can be diffi cult to measure and describe. The interest of hydrologists, geologists, biologists and farmers in water fl ow......, and its physical impact, depends on whether the main focus is on the entire stream system, the adjacent fi elds, the individual reaches or the habitats of different species. It is important to learn how to manage fl ow at all scales, in order to understand the ecology of streams and the biology...

  14. Development of microcontroller based water flow measurement

    Science.gov (United States)

    Munir, Muhammad Miftahul; Surachman, Arif; Fathonah, Indra Wahyudin; Billah, Muhammad Aziz; Khairurrijal, Mahfudz, Hernawan; Rimawan, Ririn; Lestari, Slamet

    2015-04-01

    A digital instrument for measuring water flow was developed using an AT89S52 microcontroller, DS1302 real time clock (RTC), and EEPROM for an external memory. The sensor used for probing the current was a propeller that will rotate if immersed in a water flow. After rotating one rotation, the sensor sends one pulse and the number of pulses are counted for a certain time of counting. The measurement data, i.e. the number of pulses per unit time, are converted into water flow velocity (m/s) through a mathematical formula. The microcontroller counts the pulse sent by the sensor and the number of counted pulses are stored into the EEPROM memory. The time interval for counting is provided by the RTC and can be set by the operator. The instrument was tested under various time intervals ranging from 10 to 40 seconds and several standard propellers owned by Experimental Station for Hydraulic Structure and Geotechnics (BHGK), Research Institute for Water Resources (Pusair). Using the same propellers and water flows, it was shown that water flow velocities obtained from the developed digital instrument and those found by the provided analog one are almost similar.

  15. Damping measurements in flowing water

    Science.gov (United States)

    Coutu, A.; Seeley, C.; Monette, C.; Nennemann, B.; Marmont, H.

    2012-11-01

    Fluid-structure interaction (FSI), in the form of mass loading and damping, governs the dynamic response of water turbines, such as Francis turbines. Water added mass and damping are both critical quantities in evaluating the dynamic response of the turbine component. Although the effect of fluid added mass is well documented, fluid damping, a critical quantity to limit vibration amplitudes during service, and therefore to help avoiding possible failure of the turbines, has received much less attention in the literature. This paper presents an experimental investigation of damping due to FSI. The experimental setup, designed to create dynamic characteristics similar to the ones of Francis turbine blades is discussed, together with the experimental protocol and examples of measurements obtained. The paper concludes with the calculated damping values and a discussion on the impact of the observed damping behaviour on the response of hydraulic turbine blades to FSI.

  16. Damping measurements in flowing water

    International Nuclear Information System (INIS)

    Coutu, A; Monette, C; Nennemann, B; Marmont, H; Seeley, C

    2012-01-01

    Fluid-structure interaction (FSI), in the form of mass loading and damping, governs the dynamic response of water turbines, such as Francis turbines. Water added mass and damping are both critical quantities in evaluating the dynamic response of the turbine component. Although the effect of fluid added mass is well documented, fluid damping, a critical quantity to limit vibration amplitudes during service, and therefore to help avoiding possible failure of the turbines, has received much less attention in the literature. This paper presents an experimental investigation of damping due to FSI. The experimental setup, designed to create dynamic characteristics similar to the ones of Francis turbine blades is discussed, together with the experimental protocol and examples of measurements obtained. The paper concludes with the calculated damping values and a discussion on the impact of the observed damping behaviour on the response of hydraulic turbine blades to FSI.

  17. A simple flow-concentration modelling method for integrating water ...

    African Journals Online (AJOL)

    A simple flow-concentration modelling method for integrating water quality and ... flow requirements are assessed for maintenance low flow, drought low flow ... the instream concentrations of chemical constituents that will arise from different ...

  18. Temperature transient response measurement in flowing water

    International Nuclear Information System (INIS)

    Rainbird, J.C.

    1980-01-01

    A specially developed procedure is described for determining the thermal transient response of thermocouples and other temperature transducers when totally immersed in flowing water. The high velocity heat transfer conditions associated with this facility enable thermocouple response times to be predicted in other fluids. These predictions can be confirmed by electrical analogue experiments. (author)

  19. simulation of vertical water flow through vadose zone

    African Journals Online (AJOL)

    HOD

    Simulation of vertical water flow representing the release of water from the vadose zone to the aquifer of surroundings ... ground water pollution from agricultural, industrial and municipal .... Peak Flow Characteristics of Wyoming. Streams: US ...

  20. The use of air flow through water for water evaporation

    International Nuclear Information System (INIS)

    Lashin, A.A.

    1996-01-01

    In water desalination system the productivity rate is improved by increasing the rate of eater evaporation either by heating the water or by forcing air to carry more vapor before condensation. This paper describe an experimental investigation into the effect of forcing the air to flow through a hot water contained in a closed tank through a perforated end of inlet tube. When the air bubbles pass through the water, it increases the rate of vaporization. The effect of some operating parameters are investigated and the results are presented and discussed. 6 figs

  1. Pig herd monitoring and undesirable tripping and stepping prevention

    DEFF Research Database (Denmark)

    Gronskyte, Ruta; Clemmensen, Line Katrine Harder; Hviid, Marchen Sonja

    2015-01-01

    Humane handling and slaughter of livestock are of major concern in modern societies. Monitoring animal wellbeing in slaughterhouses is critical in preventing unnecessary stress and physical damage to livestock, which can also affect the meat quality. The goal of this study is to monitor pig herds...... at the slaughterhouse and identify undesirable events such as pigs tripping or stepping on each other. In this paper, we monitor pig behavior in color videos recorded during unloading from transportation trucks. We monitor the movement of a pig herd where the pigs enter and leave a surveyed area. The method is based...... on optical flow, which is not well explored for monitoring all types of animals, but is the method of choice for human crowd monitoring. We recommend using modified angular histograms to summarize the optical flow vectors. We show that the classification rate based on support vector machines is 93% of all...

  2. The undesirable effects of neuromuscular blocking drugs

    DEFF Research Database (Denmark)

    Claudius, C; Garvey, L H; Viby-Mogensen, J

    2009-01-01

    Neuromuscular blocking drugs are designed to bind to the nicotinic receptor at the neuromuscular junction. However, they also interact with other acetylcholine receptors in the body. Binding to these receptors causes adverse effects that vary with the specificity for the cholinergic receptor...... in question. Moreover, all neuromuscular blocking drugs may cause hypersensitivity reactions. Often the symptoms are mild and self-limiting but massive histamine release can cause systematic reactions with circulatory and respiratory symptoms and signs. At the end of anaesthesia, no residual effect...... of a neuromuscular blocking drug should be present. However, the huge variability in response to neuromuscular blocking drugs makes it impossible to predict which patient will suffer postoperative residual curarization. This article discusses the undesirable effects of the currently available neuromuscular blocking...

  3. Worse than imagined: Unidentified virtual water flows in China.

    Science.gov (United States)

    Cai, Beiming; Wang, Chencheng; Zhang, Bing

    2017-07-01

    The impact of virtual water flows on regional water scarcity in China had been deeply discussed in previous research. However, these studies only focused on water quantity, the impact of virtual water flows on water quality has been largely neglected. In this study, we incorporate the blue water footprint related with water quantity and grey water footprint related with water quality into virtual water flow analysis based on the multiregional input-output model of 2007. The results find that the interprovincial virtual flows accounts for 23.4% of China's water footprint. The virtual grey water flows are 8.65 times greater than the virtual blue water flows; the virtual blue water and grey water flows are 91.8 and 794.6 Gm 3 /y, respectively. The use of the indicators related with water quantity to represent virtual water flows in previous studies will underestimate their impact on water resources. In addition, the virtual water flows are mainly derived from agriculture, chemical industry and petroleum processing and the coking industry, which account for 66.8%, 7.1% and 6.2% of the total virtual water flows, respectively. Virtual water flows have intensified both quantity- and quality-induced water scarcity of export regions, where low-value-added but water-intensive and high-pollution goods are produced. Our study on virtual water flows can inform effective water use policy for both water resources and water pollution in China. Our methodology about virtual water flows also can be used in global scale or other countries if data available. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Water flow in single rock joints

    International Nuclear Information System (INIS)

    Hakami, Eva

    1989-05-01

    To study the hydromechanical properties of single rock joints a technique to make transparent replicas of natural joint surfaces has been developed. Five different joint samples were replicated and studied. The aperture distribution of the joints were obtained through a measurement method provided by the transparent replicas. The principle behind the method is that a water drop with a known volume, which is placed inside a joint, will cover a certain area of the surface depending on the average size of aperture at the actual point. Flow tests were performed on the same joint replicas. The tortuousity of the flow and the velocity along single stream lines were measured using colour injections into the water flow through the joints. The equivalent hydraulic apertures determined from the flow tests where shown to be smaller than the average mechanical apertures. The velocity of the flow varies strongly between different paths over the joint depending on the spatial distribution of the apertures. The degree of matedness between the joint surfaces is an important factor influencing the channeling character of the joints. (author) (38 refs.)

  5. Case study on ground water flow (8)

    International Nuclear Information System (INIS)

    1999-02-01

    The report comprises research activities made in fiscal year 1997 under the contract of Japan Nuclear Fuel Cycle Development Center and the main items are: (1) Evaluation of water permeability through discontinuous hard bedrock in deep strata in relevant with underground disposal of radioactive wastes, (2) Three dimensional analysis of permeated water in bedrock, including flow analysis in T ono district using neuro-network and modification of Evaporation Logging System, (3) Development of hydraulic tests and necessary equipment applicable to measurements of complex dielectric constants of contaminated soils using FUDR-V method, this giving information on soil component materials, (4) Investigation methods and modeling of hydraulics in deep strata, (5) Geological study of ground water using environmental isotopes such as 14 C, 36 Cl and 4 He, particularly measurement of ages of ground water using an accelerator-mass spectrometer, and (6) Re-submerging phenomena affecting the long-term geological stability. (S. Ohno)

  6. Case study on ground water flow (8)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-02-01

    The report comprises research activities made in fiscal year 1997 under the contract of Japan Nuclear Fuel Cycle Development Center and the main items are: (1) Evaluation of water permeability through discontinuous hard bedrock in deep strata in relevant with underground disposal of radioactive wastes, (2) Three dimensional analysis of permeated water in bedrock, including flow analysis in T ono district using neuro-network and modification of Evaporation Logging System, (3) Development of hydraulic tests and necessary equipment applicable to measurements of complex dielectric constants of contaminated soils using FUDR-V method, this giving information on soil component materials, (4) Investigation methods and modeling of hydraulics in deep strata, (5) Geological study of ground water using environmental isotopes such as {sup 14}C, {sup 36}Cl and {sup 4}He, particularly measurement of ages of ground water using an accelerator-mass spectrometer, and (6) Re-submerging phenomena affecting the long-term geological stability. (S. Ohno)

  7. Stability of people exposed to water flows

    Directory of Open Access Journals (Sweden)

    E. Martínez-Gomariz

    2016-01-01

    Full Text Available Our cities are formed by several elements which are exposed to floods of a magnitude according to the importance of the rainfall event and the design of the urban drainage system. The most important components in the cities are the pedestrians who develop various activities during rain events. Focusing on pedestrians, the research on their stability when they are exposed to water flows provides the necessary knowledge to understand and manage the associated hazard for them. In this research, several experiments with humans were carried out in order to determine the stability limits to pedestrians crossing through a water flow in a real scale platform. The results obtained and by comparing those with human stability criteria proposed by other authors and guidelines provide a more restrictive criterion.

  8. Augmentation of forced flow boiling heat transfer by introducing air flow into subcooled water flow

    International Nuclear Information System (INIS)

    Koizumi, Y.; Ohtake, H.; Yuasa, T.; Matsushita, N.

    2001-01-01

    The effect of air injection into a subcooled water flow on boiling heat transfer and a critical heat flux (CHF) was examined experimentally. Experiments were conducted in the range of subcooling of 50 K, a superficial velocity of water and air Ul = 0.17 ∼ 3.4 and Ug = 0 ∼ 15 m/s, respectively. A test heat transfer surface was a 5 mm wide, 40 mm long and 0.5 mm thick stainless steel sheet embedded on the bottom wall of a 10 mm high and 20 mm wide rectangular flow channel. Nine times enhancement of the heat transfer coefficient in the non-boiling region was attained at the most by introducing an air flow into a water single-phase flow. The heat transfer improvement was prominent when the water flow rate was low and the air introduction was large. The present results of the non-boiling heat transfer were well correlated with the Lockhart-Martinelli parameter X tt ; h TP /h L0 = 5.0(1/ X tt ) 0.5 . The air introduction has some effect on the augmentation of heat transfer in the boiling region, however, the two-phase flow effect was little and the boiling was dominant in the fully developed boiling region. The CHF was improved a little by the air introduction in the high water flow region. However, that was rather greatly reduced in the low flow region. Even so, the general trend by the air introduction was that qCHF increased as the air introduction was increased. The heat transfer augmentation in the non-boiling region was attained by less power increase than that in the case that only the water flow rate was increased. From the aspect of the power consumption and the heat transfer enhancement, the small air introduction in the low water flow rate region seemed more profitable, although the air introduction in the high water flow rate region and also the large air introduction were still effective in the augmentation of the heat transfer in the non-boiling region. (author)

  9. Detection of behind casing water flow at an angle to the axis of a well borehole

    International Nuclear Information System (INIS)

    1980-01-01

    Methods and apparatus for detecting the undesired flow of water in cement channels or voids behind the casing in a producing well are described. A source of high-energy neutrons (approx. 14 MeV) is placed inside the well borehole opposite the area to be investigated for cement channelling, and used to irradiate the area. An oxygen 16 nucleus is transmuted upon capture of an approximately 10 MeV neutron to radioactive nitrogen 16. This decays with a half life of 7.1 sec by emission of a beta particle and high energy gamma rays. With a sufficiently high flux of bombarding neutrons enough nitrogen 16 is created to be detected at a pair of longitudinally spaced detectors. This measurement can be used directly to indicate the speed of flow of water in the cement channels. However the volume flow rate can be determined from the detection of the high energy gamma rays from the decay of the nitrogen 16. If a pulsed neutron source is used a more accurate detection is provided. The angle of flow can be determined by suitable instrumentation. Full specifications are given. (U.K.)

  10. Enhanced DEA model with undesirable output and interval data for rice growing farmers performance assessment

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Sahubar Ali Mohd. Nadhar, E-mail: sahubar@uum.edu.my; Ramli, Razamin, E-mail: razamin@uum.edu.my; Baten, M. D. Azizul, E-mail: baten-math@yahoo.com [School of Quantitative Sciences, UUM College of Arts and Sciences, Universiti Utara Malaysia, 06010 Sintok, Kedah (Malaysia)

    2015-12-11

    Agricultural production process typically produces two types of outputs which are economic desirable as well as environmentally undesirable outputs (such as greenhouse gas emission, nitrate leaching, effects to human and organisms and water pollution). In efficiency analysis, this undesirable outputs cannot be ignored and need to be included in order to obtain the actual estimation of firms efficiency. Additionally, climatic factors as well as data uncertainty can significantly affect the efficiency analysis. There are a number of approaches that has been proposed in DEA literature to account for undesirable outputs. Many researchers has pointed that directional distance function (DDF) approach is the best as it allows for simultaneous increase in desirable outputs and reduction of undesirable outputs. Additionally, it has been found that interval data approach is the most suitable to account for data uncertainty as it is much simpler to model and need less information regarding its distribution and membership function. In this paper, an enhanced DEA model based on DDF approach that considers undesirable outputs as well as climatic factors and interval data is proposed. This model will be used to determine the efficiency of rice farmers who produces undesirable outputs and operates under uncertainty. It is hoped that the proposed model will provide a better estimate of rice farmers’ efficiency.

  11. Enhanced DEA model with undesirable output and interval data for rice growing farmers performance assessment

    International Nuclear Information System (INIS)

    Khan, Sahubar Ali Mohd. Nadhar; Ramli, Razamin; Baten, M. D. Azizul

    2015-01-01

    Agricultural production process typically produces two types of outputs which are economic desirable as well as environmentally undesirable outputs (such as greenhouse gas emission, nitrate leaching, effects to human and organisms and water pollution). In efficiency analysis, this undesirable outputs cannot be ignored and need to be included in order to obtain the actual estimation of firms efficiency. Additionally, climatic factors as well as data uncertainty can significantly affect the efficiency analysis. There are a number of approaches that has been proposed in DEA literature to account for undesirable outputs. Many researchers has pointed that directional distance function (DDF) approach is the best as it allows for simultaneous increase in desirable outputs and reduction of undesirable outputs. Additionally, it has been found that interval data approach is the most suitable to account for data uncertainty as it is much simpler to model and need less information regarding its distribution and membership function. In this paper, an enhanced DEA model based on DDF approach that considers undesirable outputs as well as climatic factors and interval data is proposed. This model will be used to determine the efficiency of rice farmers who produces undesirable outputs and operates under uncertainty. It is hoped that the proposed model will provide a better estimate of rice farmers’ efficiency

  12. Enhanced DEA model with undesirable output and interval data for rice growing farmers performance assessment

    Science.gov (United States)

    Khan, Sahubar Ali Mohd. Nadhar; Ramli, Razamin; Baten, M. D. Azizul

    2015-12-01

    Agricultural production process typically produces two types of outputs which are economic desirable as well as environmentally undesirable outputs (such as greenhouse gas emission, nitrate leaching, effects to human and organisms and water pollution). In efficiency analysis, this undesirable outputs cannot be ignored and need to be included in order to obtain the actual estimation of firms efficiency. Additionally, climatic factors as well as data uncertainty can significantly affect the efficiency analysis. There are a number of approaches that has been proposed in DEA literature to account for undesirable outputs. Many researchers has pointed that directional distance function (DDF) approach is the best as it allows for simultaneous increase in desirable outputs and reduction of undesirable outputs. Additionally, it has been found that interval data approach is the most suitable to account for data uncertainty as it is much simpler to model and need less information regarding its distribution and membership function. In this paper, an enhanced DEA model based on DDF approach that considers undesirable outputs as well as climatic factors and interval data is proposed. This model will be used to determine the efficiency of rice farmers who produces undesirable outputs and operates under uncertainty. It is hoped that the proposed model will provide a better estimate of rice farmers' efficiency.

  13. Method for confirming flow pattern of gas-water flow in horizontal tubes under rolling state

    International Nuclear Information System (INIS)

    Luan Feng; Yan Changqi

    2008-01-01

    An experimental study on the flow patterns of gas-water flow was carried out in horizontal tubes under rolling state. It was found that the pressure drop of two phase flow was with an obvious periodical characteristic. The flow pattern of the gas-water flow was distinguished according to the characteristics of the pressure drop in this paper. It was proved that the characteristics of the pressure drop can distinguish the flow pattern of gas-water flow correctly through comparing with the result of careful observation and high speed digital camera. (authors)

  14. Eye wash water flow direction study: an evaluation of the effectiveness of eye wash devices with opposite directional water flow.

    Science.gov (United States)

    Fogt, Jennifer S; Jones-Jordan, Lisa A; Barr, Joseph T

    2018-01-01

    New designs of eye wash stations have been developed in which the direction of water flow from the fountain has been reversed, with two water streams originating nasally in both eyes and flowing toward the temporal side of each eye. No study has been done to determine the ideal direction of water flow coming from the eye wash in relation to the eye. Ophthalmic eye examinations were conducted before and after the use of two eye wash stations with opposite water flow directionality. Fluorescein was instilled in both eyes before using an eye wash to measure the effectiveness of the water flow. Subjects were surveyed upon their experiences using the eye washes. Ophthalmic examination found no significant difference in the efficacy of the eye washes with nasal-to-temporal water flow when compared to temporal-to-nasal water flow direction.

  15. The metabolic regimes of flowing waters

    Science.gov (United States)

    Bernhardt, Emily S.; Heffernan, Jim B.; Grimm, Nancy B.; Stanley, Emily H.; Harvey, Judson; Arroita, M.; Appling, Alison; Cohen, M.J.; McDowell, William H.; Hall, R.O.; Read, Jordan S.; Roberts, B.J.; Stets, Edward; Yackulic, Charles B.

    2018-01-01

    The processes and biomass that characterize any ecosystem are fundamentally constrained by the total amount of energy that is either fixed within or delivered across its boundaries. Ultimately, ecosystems may be understood and classified by their rates of total and net productivity and by the seasonal patterns of photosynthesis and respiration. Such understanding is well developed for terrestrial and lentic ecosystems but our understanding of ecosystem phenology has lagged well behind for rivers. The proliferation of reliable and inexpensive sensors for monitoring dissolved oxygen and carbon dioxide is underpinning a revolution in our understanding of the ecosystem energetics of rivers. Here, we synthesize our current understanding of the drivers and constraints on river metabolism, and set out a research agenda aimed at characterizing, classifying and modeling the current and future metabolic regimes of flowing waters.

  16. A water flow calorimeter calibration system

    International Nuclear Information System (INIS)

    Ullrich, F.T.

    1983-01-01

    Neutral beam systems are instrumented by several water flow calorimeter systems, and some means is needed to verify the accuracy of such systems and diagnose their failures. This report describes a calibration system for these calorimeters. The calibrator consists of two 24 kilowatt circulation water heaters, with associated controls and instrumentation. The unit can supply power from 0 to 48 kW in five coarse steps and one fine range. Energy is controlled by varying the power and the time of operation of the heaters. The power is measured by means of precision power transducers, and the energy is measured by integrating the power with respect to time. The accuracy of the energy measurement is better than 0.5% when the power supplied is near full scale, and the energy resolution is better than 1 kilojoule. The maximum energy delivered is approximately 50 megajoules. The calorimetry loop to be calibrated is opened, and the calibrator is put in series with the calorimeter heat source. The calorimeter is then operated in its normal fashion, with the calibrator used as the heat source. The calibrator can also be used in a stand alone mode to calibrate calorimeter sensors removed from systems

  17. Ground-water flow and quality in the Atlantic City 800-foot sand, New Jersey

    Science.gov (United States)

    McAuley, Steven D.; Barringer, Julia L.; Paulachok, Gary N.; Clark, Jeffrey S.; Zapecza, Otto S.

    2001-01-01

    reported for water in a former supply well in southern Cape May County. These data indicate that salty water has moved inland in Cape May County. Analysis of the chloride-concentration data indicates that ground water with a chloride concentration of 250 mg/L is within 4 miles of supply wells in Stone Harbor, Cape May County, and is about 10 miles offshore of supply wells near Atlantic City. Results of numerical simulations of ground-water flow were analyzed to determine the effects of four water-supply alternatives on water levels, the flow budget, and potential saltwater movement toward pumping centers during 1986-2040. In the supply alternatives, pumpage is (1) held constant at 1986 rates of pumpage; (2) increased by 35 percent at 1986 locations; (3) increased by 35 percent, but with relocation of some supply wells further inland; and (4) increased by 35 percent but with some of the increase derived from inland wells tapping the Kirkwood-Cohansey aquifer system rather than the Atlantic City 800-foot sand. Inland relocation of supply wells closer to the updip limit of the overlying confining unit results in the smallest decline in water levels and the smallest rate of ground-water flow between the offshore location of salty water and coastal supply wells. Increased pumpage from coastal supply wells results in the greatest water-level declines and the greatest increase in the rate of ground-water flow from offshore to coastal wells. Flow of undesirable salty ground water from offshore locations remains nearly the same as for current (1986) conditions when pumping rates do not change, and the flow-rate increase is smallest for the relocated pumpage (fourth) alternative. In comparing the two conditions of a 35-percent increase in pumpage, the flow from undesirable salty water positions is lessened and flow from the unconfined aquifer is increased when some of the pumping centers are relocated farther inland. Ground water from the 250-mg/L isochlor position does not reach

  18. Complex networks from experimental horizontal oil–water flows: Community structure detection versus flow pattern discrimination

    International Nuclear Information System (INIS)

    Gao, Zhong-Ke; Fang, Peng-Cheng; Ding, Mei-Shuang; Yang, Dan; Jin, Ning-De

    2015-01-01

    We propose a complex network-based method to distinguish complex patterns arising from experimental horizontal oil–water two-phase flow. We first use the adaptive optimal kernel time–frequency representation (AOK TFR) to characterize flow pattern behaviors from the energy and frequency point of view. Then, we infer two-phase flow complex networks from experimental measurements and detect the community structures associated with flow patterns. The results suggest that the community detection in two-phase flow complex network allows objectively discriminating complex horizontal oil–water flow patterns, especially for the segregated and dispersed flow patterns, a task that existing method based on AOK TFR fails to work. - Highlights: • We combine time–frequency analysis and complex network to identify flow patterns. • We explore the transitional flow behaviors in terms of betweenness centrality. • Our analysis provides a novel way for recognizing complex flow patterns. • Broader applicability of our method is demonstrated and articulated

  19. Research for rolling effects on flow pattern of gas-water flow in horizontal tubes

    International Nuclear Information System (INIS)

    Luan Feng; Yan Changqi

    2007-01-01

    The flow pattern transition of two-phase flow is caused by the inertial force resulted from rolling and incline of horizontal tubes under rolling state. an experimental study on the flow patterns of gas-water flow was carried out in horizontal tubes under rolling state, which rolling period is 15 second and rolling angle is 10 degrees, and a pattern flow picture is shown. It was found that there are two flow patterns in one rolling period under some gas flux and water flux. (authors)

  20. Single-phase flow and flow boiling of water in horizontal rectangular microchannels

    OpenAIRE

    Mirmanto

    2013-01-01

    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University The current study is part of a long term experimental project devoted to investigating single-phase flow pressure drop and heat transfer, flow boiling pressure drop and heat transfer, flow boiling instability and flow visualization of de-ionized water flow in microchannels. The experimental facility was first designed and constructed by S. Gedupudi (2009) and in the present study; ...

  1. Modelling of flow and settling in storm water sedimentation tanks

    OpenAIRE

    Kluck, J.

    1994-01-01

    In the near future in the Netherlands many reservoirs will have to be built to abate the pollution of the surface water by overflowing storm water from combined sewer systems [Kluck, 1992-a]. These reservoirs, called storm water sedimentation tanks, reduce the pollution in two ways. The most important is by simply storing a part of the sewage (waste water and storm water) and thus reducing the quantity of overflowing water. The second is by providing flow conditions in which particles can set...

  2. On phonons and water flow enhancement in carbon nanotubes

    DEFF Research Database (Denmark)

    Cruz-Chu, Eduardo R.; Papadopoulou, Ermioni; Walther, Jens Honore

    2017-01-01

    The intriguing physics of water transport through carbon nanotubes (CNTs) has motivated numerous studies, reporting flow rates higher than those estimated by continuum models1. The quantification of water transport in CNTs remains unresolved, however, with flow rates reported by different...

  3. Determinants of virtual water flows in the Mediterranean.

    Science.gov (United States)

    Fracasso, Andrea; Sartori, Martina; Schiavo, Stefano

    2016-02-01

    The aim of the paper is to investigate the main determinants of the bilateral virtual water (water used in the production of a commodity or service) flows associated with international trade in agricultural goods across the Mediterranean basin. We consider the bilateral gross flows of virtual water in the area and study what export-specific and import-specific factors are significantly associated with virtual water flows. We follow a sequential approach. Through a gravity model of trade, we obtain a "refined" version of the variable we aim to explain, one that is free of the amount of flows due to pair-specific factors affecting bilateral trade flows and that fully reflects the impact of country-specific determinants of virtual water trade. A number of country-specific potential explanatory variables, ranging from water endowments to trade barriers, from per capita GDP to irrigation prices, is presented and tested. To identify the variables that help to explain the bilateral flows of virtual water, we adopt a model selection procedure based on model averaging. Our findings confirm one of the main controversial results in the literature: larger water endowments do not necessarily lead to a larger 'export' of virtual water, as one could expect. We also find some evidence that higher water irrigation prices reduce (increase) virtual water 'exports' ('imports'). Copyright © 2015 Elsevier B.V. All rights reserved.

  4. EFFECTS OF EXCESS URBAN RUNOFF ON WASTE WATER FLOW IN PÉCS, HUNGARY

    Directory of Open Access Journals (Sweden)

    L. RONCZYK

    2012-12-01

    Full Text Available Global warming has been leading to climate change that is predicted to cause an increase in the frequency and intensity of rainfall. Urban areas must be designed to cope with the undesired effect and risks associated with stormwater runoff. Stormwater, entering into the sewerage of Pécs, SW Hungary, exerts an extra load on wastewater and sewage transfer in the underground pipeline system. Based on precipitation and pumping station flow data, we identified a strong correspondence between rainfall and flow behavior in Pécs. We also determined the types of foreign waters entering the sewerage according to their source and origin. Our study also indicates that 32% of the entire land area has a low-degree infrastructure for cutting-edge stormwater drainage and management. The results of the current research aid to evaluate the adequate methodology for risk analysis of each sewage catchment. The spatial analysis of waste water system and its physical and human geographical environment became an effective tool to help the local waterworks (Tettye Forrásház Ltd. to estimate potential hazard level in each sewage catchment and allocate and distribute pumping costs and efforts among the pumping stations during spatiallyheterogeneous torrential rainfall events.

  5. Self Calibrating Flow Estimation in Waste Water Pumping Stations

    DEFF Research Database (Denmark)

    Kallesøe, Carsten Skovmose; Knudsen, Torben

    2016-01-01

    Knowledge about where waste water is flowing in waste water networks is essential to optimize the operation of the network pumping stations. However, installation of flow sensors is expensive and requires regular maintenance. This paper proposes an alternative approach where the pumps and the waste...... water pit are used for estimating both the inflow and the pump flow of the pumping station. Due to the nature of waste water, the waste water pumps are heavily affected by wear and tear. To compensate for the wear of the pumps, the pump parameters, used for the flow estimation, are automatically...... calibrated. This calibration is done based on data batches stored at each pump cycle, hence makes the approach a self calibrating system. The approach is tested on a pumping station operating in a real waste water network....

  6. Imaging water velocity and volume fraction distributions in water continuous multiphase flows using inductive flow tomography and electrical resistance tomography

    International Nuclear Information System (INIS)

    Meng, Yiqing; Lucas, Gary P

    2017-01-01

    This paper presents the design and implementation of an inductive flow tomography (IFT) system, employing a multi-electrode electromagnetic flow meter (EMFM) and novel reconstruction techniques, for measuring the local water velocity distribution in water continuous single and multiphase flows. A series of experiments were carried out in vertical-upward and upward-inclined single phase water flows and ‘water continuous’ gas–water and oil–gas–water flows in which the velocity profiles ranged from axisymmetric (single phase and vertical-upward multiphase flows) to highly asymmetric (upward-inclined multiphase flows). Using potential difference measurements obtained from the electrode array of the EMFM, local axial velocity distributions of the continuous water phase were reconstructed using two different IFT reconstruction algorithms denoted RT#1, which assumes that the overall water velocity profile comprises the sum of a series of polynomial velocity components, and RT#2, which is similar to RT#1 but which assumes that the zero’th order velocity component may be replaced by an axisymmetric ‘power law’ velocity distribution. During each experiment, measurement of the local water volume fraction distribution was also made using the well-established technique of electrical resistance tomography (ERT). By integrating the product of the local axial water velocity and the local water volume fraction in the cross section an estimate of the water volumetric flow rate was made which was compared with a reference measurement of the water volumetric flow rate. In vertical upward flows RT#2 was found to give rise to water velocity profiles which are consistent with the previous literature although the profiles obtained in the multiphase flows had relatively higher central velocity peaks than was observed for the single phase profiles. This observation was almost certainly a result of the transfer of axial momentum from the less dense dispersed phases to the

  7. Imaging water velocity and volume fraction distributions in water continuous multiphase flows using inductive flow tomography and electrical resistance tomography

    Science.gov (United States)

    Meng, Yiqing; Lucas, Gary P.

    2017-05-01

    This paper presents the design and implementation of an inductive flow tomography (IFT) system, employing a multi-electrode electromagnetic flow meter (EMFM) and novel reconstruction techniques, for measuring the local water velocity distribution in water continuous single and multiphase flows. A series of experiments were carried out in vertical-upward and upward-inclined single phase water flows and ‘water continuous’ gas-water and oil-gas-water flows in which the velocity profiles ranged from axisymmetric (single phase and vertical-upward multiphase flows) to highly asymmetric (upward-inclined multiphase flows). Using potential difference measurements obtained from the electrode array of the EMFM, local axial velocity distributions of the continuous water phase were reconstructed using two different IFT reconstruction algorithms denoted RT#1, which assumes that the overall water velocity profile comprises the sum of a series of polynomial velocity components, and RT#2, which is similar to RT#1 but which assumes that the zero’th order velocity component may be replaced by an axisymmetric ‘power law’ velocity distribution. During each experiment, measurement of the local water volume fraction distribution was also made using the well-established technique of electrical resistance tomography (ERT). By integrating the product of the local axial water velocity and the local water volume fraction in the cross section an estimate of the water volumetric flow rate was made which was compared with a reference measurement of the water volumetric flow rate. In vertical upward flows RT#2 was found to give rise to water velocity profiles which are consistent with the previous literature although the profiles obtained in the multiphase flows had relatively higher central velocity peaks than was observed for the single phase profiles. This observation was almost certainly a result of the transfer of axial momentum from the less dense dispersed phases to the water

  8. Measuring scarce water saving from interregional virtual water flows in China

    Science.gov (United States)

    Zhao, X.; Li, Y. P.; Yang, H.; Liu, W. F.; Tillotson, M. R.; Guan, D.; Yi, Y.; Wang, H.

    2018-05-01

    Trade of commodities can lead to virtual water flows between trading partners. When commodities flow from regions of high water productivity to regions of low water productivity, the trade has the potential to generate water saving. However, this accounting of water saving does not account for the water scarcity status in different regions. It could be that the water saving generated from this trade occurs at the expense of the intensified water scarcity in the exporting region, and exerts limited effect on water stress alleviation in importing regions. In this paper, we propose an approach to measure the scarce water saving associated with virtual water trade (measuring in water withdrawal/use). The scarce water is quantified by multiplying the water use in production with the water stress index (WSI). We assessed the scarce water saving/loss through interprovincial trade within China using a multi-region input-output table from 2010. The results show that interprovincial trade resulted in 14.2 km3 of water loss without considering water stress, but only 0.4 km3 scarce water loss using the scarce water concept. Among the 435 total connections of virtual water flows, 254 connections contributed to 20.2 km3 of scarce water saving. Most of these connections are virtual water flows from provinces with lower WSI to that with higher WSI. Conversely, 175 connections contributed to 20.6 km3 of scarce water loss. The virtual water flow connections between Xinjiang and other provinces stood out as the biggest contributors, accounting for 66% of total scarce water loss. The results show the importance of assessing water savings generated from trade with consideration of both water scarcity status and water productivity across regions. Identifying key connections of scarce water saving is useful in guiding interregional economic restructuring towards water stress alleviation, a major goal of China’s sustainable development strategy.

  9. 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

  10. Modeling shallow water flows using the discontinuous Galerkin method

    CERN Document Server

    Khan, Abdul A

    2014-01-01

    Replacing the Traditional Physical Model Approach Computational models offer promise in improving the modeling of shallow water flows. As new techniques are considered, the process continues to change and evolve. Modeling Shallow Water Flows Using the Discontinuous Galerkin Method examines a technique that focuses on hyperbolic conservation laws and includes one-dimensional and two-dimensional shallow water flows and pollutant transports. Combines the Advantages of Finite Volume and Finite Element Methods This book explores the discontinuous Galerkin (DG) method, also known as the discontinuous finite element method, in depth. It introduces the DG method and its application to shallow water flows, as well as background information for implementing and applying this method for natural rivers. It considers dam-break problems, shock wave problems, and flows in different regimes (subcritical, supercritical, and transcritical). Readily Adaptable to the Real World While the DG method has been widely used in the fie...

  11. Investigation of the mixture flow rates of oil-water two-phase flow using the turbine flow meter

    International Nuclear Information System (INIS)

    Li Donghui; Feng Feifei; Wu Yingxiang; Xu Jingyu

    2009-01-01

    In this work, the mixture flow rate of oil-water flows was studied using the turbine flow-meter. The research emphasis focuses on the effect of oil viscosity and input fluids flow rates on the precision of the meter. Experiments were conducted to measure the in-situ mixture flow rate in a horizontal pipe with 0.05m diameter using seven different viscosities of white oil and tap water as liquid phases. Results showed that both oil viscosity and input oil fraction exert a remarkable effect on measured results, especially when the viscosity of oil phase remained in the area of high value. In addition, for metering mixture flow rate using turbine flow-meter, the results are not sensitive to two-phase flow pattern according to the experimental data.

  12. A water budget approach to instream flow maintenance

    International Nuclear Information System (INIS)

    Waddle, T.

    1991-01-01

    Storage reallocation is a current issue at many Federal water storage facilities that have hydroelectric generation. Allocation of storage to support instream flows is one of the changes being considered. In this paper, a portion of storage is dedicated to supplying instream flows. The author defines this storage account as a water budget and operate it to provide instream habitat below the reservoir. The author uses a limiting event model, the effective habitat time series, to determine when water budget releases will produce habitat benefits. The effective habitat time series acts as a surrogate for fish population and reflects the mid to long term influence of water management decisions on the life cycle of a fish species. The author develops an operation rule for the water budget that considers water rights and habitat events. The paper concludes by contrasting the habitat benefits of water budget operation with fixed minimum flow requirements

  13. (Virtual) Water Flows Uphill toward Money.

    Science.gov (United States)

    Wang, Ranran; Hertwich, Edgar; Zimmerman, Julie B

    2016-11-15

    This study provides a more precise understanding of the main driving forces of anthropogenic water use across countries. The anthropogenic water use was distinguished as blue water (i.e., fresh surface and groundwater) and total water (i.e. blue + green water; green water is rainwater insofar as it does not become runoff) used for producing, consuming, exporting, and importing of primary and manufactured goods and services, measured on a per country and per capita basis. The population effect on national blue water consumption associated with producing and consuming was found to be bigger than what the commonly assumed unitary population elasticity indicates. Distinct from the homogeneous affluence-water relationships conventionally assumed, this study revealed varying and potentially opposite effects affluence can have depending on the water use account of interest (e.g., production-based or consumption-based, blue or green) and the income level. Affluence, not the availability of freshwater resources, was found to be the most critical driver of virtual water imports. And a more affluent lifestyle in high-income countries was still associated with greater blue water consumption. With each doubling of income, blue water embedded in the goods and services a nation consumed and imported on a per capita basis increased by 82% and 86%, respectively, across the 110 countries analyzed for 2007. In comparison to affluence, the varying per capita water consumption accounts across the nations were much less sensitive to food consumption patterns. Given its critical role for water, land, and energy use shown by this and previous studies, affluence should be taken as a critical factor in future studies to better understand and leverage the water-energy-food-land nexus.

  14. Microelement Exploration Water Flow of Rimnik River

    OpenAIRE

    , N. Bajraktari; , B. Baraj; , T. Arbneshi; , S. Jusufi

    2016-01-01

    Compared to the increasing need on qualitative water use, many water şows are subject to a rising pollution by urban and industrial untreated water discharge, and in some cases by incidental run-offs. Besides them, there is also a great impact made by disseminated agricultural pollution and air and soil rinsing after atmospheric rainfalls. The main purpose of this paper is the micro-element exploration in water and sediments, along the water şow of Rimnik River. Some of the heavy metals: Pb, ...

  15. Regression modeling of ground-water flow

    Science.gov (United States)

    Cooley, R.L.; Naff, R.L.

    1985-01-01

    Nonlinear multiple regression methods are developed to model and analyze groundwater flow systems. Complete descriptions of regression methodology as applied to groundwater flow models allow scientists and engineers engaged in flow modeling to apply the methods to a wide range of problems. Organization of the text proceeds from an introduction that discusses the general topic of groundwater flow modeling, to a review of basic statistics necessary to properly apply regression techniques, and then to the main topic: exposition and use of linear and nonlinear regression to model groundwater flow. Statistical procedures are given to analyze and use the regression models. A number of exercises and answers are included to exercise the student on nearly all the methods that are presented for modeling and statistical analysis. Three computer programs implement the more complex methods. These three are a general two-dimensional, steady-state regression model for flow in an anisotropic, heterogeneous porous medium, a program to calculate a measure of model nonlinearity with respect to the regression parameters, and a program to analyze model errors in computed dependent variables such as hydraulic head. (USGS)

  16. Globalisation of water resources: International virtual water flows in relation to international crop trade

    NARCIS (Netherlands)

    Hoekstra, Arjen Ysbert; Hung, P.Q.

    2005-01-01

    The water that is used in the production process of a commodity is called the ‘virtual water’ contained in the commodity. International trade of commodities brings along international flows of virtual water. The objective of this paper is to quantify the volumes of virtual water flows between

  17. Critical heat flux and flow pattern for water flow in annular geometry

    International Nuclear Information System (INIS)

    Park, Jae Wook; Baek, Won Pil; Chang, Soon Heung

    1996-01-01

    An experimental study on critical heat flux (CHF) and two-phase flow visualization has been performed for water flow in internally-heated, vertical, concentric annuli under near atmospheric pressure. Tests have been done under stable forced-circulation, upward and downward flow conditions with three test sections of relatively large gap widths (heated length = 0.6 m, inner diameter = 19 mm, outer diameter = 29, 35 and 51 mm). The outer wall of the test section was made up of the transparent Pyrex tube to allow the observation of flow patterns near the CHF occurrence. The CHF mechanism was changed in the order of flooding, churn-to-annular flow transition, and local dryout under a large bubble in churn flow as the flow rate was increased from zero to higher values. Observed parametric trends are consistent with the previous understanding except that the CHF for downward flow is considerably lower than that for upward flow

  18. An electrode polarization impedance based flow sensor for low water flow measurement

    International Nuclear Information System (INIS)

    Yan, Tinghu; Sabic, Darko

    2013-01-01

    This note describes an electrode polarization impedance based flow sensor for low water flow measurement. It consists of two pairs of stainless steel electrodes set apart and inserted into a non-conductive flow tube with each pair of electrodes placed diametrically at the opposite sides. The flow sensor is modeled as a typical four-electrode system of which two electrodes are current-carrying and the other two serve as output pick ups. The polarization impedances of the two current carrying electrodes are affected by water flows resulting in changes of differential potential between the two pick-up electrodes which are separated by the same fluid. The interrogation of the two excitation electrodes with dc biased ac signals offers significantly higher sensor sensitivities to flow. The prototype flow sensor constructed for a 20 mm diameter pipeline was able to measure water flow rate as low as tested at 1.06 l h −1 and remained sensitive at a flow rate of 25.18 l h −1 when it was driven with a sinusoidal voltage at 1000 Hz with a peak ac amplitude of 2 V and a dc offset of +8 V. The nonlinear characteristics of the sensor response indicate that the sensor is more sensitive at low flows and will not be able to measure at very high flows. Additional experiments are needed to evaluate the influences of impurities, chemical species, ions constituents, conductivity and temperature over a practical range of residential water conditions, the effects of fluctuating ground signals, measurement uncertainty, power consumption, compensation of effects and practical operations. The flow sensor (principle) presented may be used as (in) a secondary sensor in combination with an existing electronic water meter to extend the low end of measurement range in residential water metering. (technical design note)

  19. Undesirable compounds in oils and fats: analysis and regulation

    Directory of Open Access Journals (Sweden)

    Lacoste Florence

    2003-03-01

    Full Text Available The aim of this paper is to present, for some undesirable compounds representative of the major origins, a comparison between the efficiency of the analytical methods used (sensitivity, precision and existing regulations. An idea of the different origins of the presence of undesirable compounds in oils and fats is given. Then a focus is done on guidelines on contaminant analysis provided by European directives or Codex Alimentarius. The reliability of some existing test methods compared to regulations is also examined: lead, hexane, polycyclic aromatic hydrocarbons, and pesticide residues.

  20. A safety control device for detecting undesirable conditions

    Energy Technology Data Exchange (ETDEWEB)

    1974-09-26

    The invention relates to safety control devices. It deals with a device adapted to transmit a warning signal and to the detection of an undesirable condition in an associated apparatus, said device comprising switching means comprising transistors mounted in a reaction path, feeding means for opening the switching means whenever an undesirable condition has been detected by sensors, whereby an oscillator is caused to stop oscillating, and an outlet device controlled by the oscillator stoppage. This can be applied to the supervision of nuclear reactor.

  1. Eye wash water flow direction study: an evaluation of the effectiveness of eye wash devices with opposite directional water flow

    OpenAIRE

    Fogt JS; Jones-Jordan LA; Barr JT

    2018-01-01

    Jennifer S Fogt, Lisa A Jones-Jordan, Joseph T Barr The Ohio State University College of Optometry, Columbus, OH, USA Introduction: New designs of eye wash stations have been developed in which the direction of water flow from the fountain has been reversed, with two water streams originating nasally in both eyes and flowing toward the temporal side of each eye. No study has been done to determine the ideal direction of water flow coming from the eye wash in relation to the eye. Materials ...

  2. Measurement of organ blood flow using tritiated water. II. Uterine blood flow in conscious pregnant ewes

    International Nuclear Information System (INIS)

    Brown, B.W.; Oddy, V.H.; Jones, A.W.

    1982-01-01

    Total uterine blood flow was measured with a tritiated water (TOH) diffusion method and with radioactive microspheres in six, conscious, pregnant ewes. With continuous infusion of TOH, equilibrium between the TOH concentration in utero-ovarian venous blood and arterial blood was attained within 50 min of the start of the infusion. The concentration of TOH in uterine and foetal tissue and in foetal blood water was the same as that in uterine venous water by 40 min; at this time, the concentration of TOH in the water of amniotic and allantoic fluids was 96% of that in uterine venous blood water. Estimates of total uterine blood flow obtained using TOH were highly correlated with those obtained with microspheres and the corresponding mean flow values obtained with the two techniques did not significantly differ. The percentage of the total uterine blood flow passing through arteriovenous anastomoses ranged from 1.4 to 3.3%

  3. Bridge pressure flow scour for clear water conditions

    Science.gov (United States)

    2009-10-01

    The equilibrium scour at a bridge caused by pressure flow with critical approach velocity in clear-water simulation conditions was studied both analytically and experimentally. The flume experiments revealed that (1) the measured equilibrium scour pr...

  4. Multiscale simulation of water flow past a C540 fullerene

    DEFF Research Database (Denmark)

    Walther, Jens Honore; Praprotnik, Matej; Kotsalis, Evangelos M.

    2012-01-01

    We present a novel, three-dimensional, multiscale algorithm for simulations of water flow past a fullerene. We employ the Schwarz alternating overlapping domain method to couple molecular dynamics (MD) of liquid water around the C540 buckyball with a Lattice–Boltzmann (LB) description for the Nav......We present a novel, three-dimensional, multiscale algorithm for simulations of water flow past a fullerene. We employ the Schwarz alternating overlapping domain method to couple molecular dynamics (MD) of liquid water around the C540 buckyball with a Lattice–Boltzmann (LB) description...

  5. Governing urban water flows in China

    NARCIS (Netherlands)

    Zhong, L.

    2007-01-01

    China has been witnessing an unprecedented period of continuous high economic growth during the past three decades. But this has been paralleled by severe environmental challenges, of which water problems are of key importance. This thesis addresses the urban water challenges of contemporary China,

  6. Water flow characteristics of rock fractures

    International Nuclear Information System (INIS)

    Joensson, Lennart

    1990-03-01

    This report has been worked out within the project 'Groundwater flow and dispersion processes in fractured rock' supported by the National Board for Spent Nuclear Fuel (SKN) in Sweden, dnr 96/85. This project is attached to the safety problems involved in the final disposal of spent nuclear fuel. The purpose of the report is to give a survey of the knowledge of fracture characteristics and to discuss this knowledge in relation to the modelling of flow and dispersion of radioactive substances in the fractures

  7. Linking flow, water quality and potential effects on aquatic biota ...

    African Journals Online (AJOL)

    Linking the potential effects of altered water quality on aquatic biota, that may result from a change in the flow (discharge) regime, is an essential step in the maintenance of riverine ecological functioning. Determination of the environmental flow requirement of a river (as well as other activities, such as classifying the ...

  8. Modelling flow dynamics in water distribution networks using ...

    African Journals Online (AJOL)

    One such approach is the Artificial Neural Networks (ANNs) technique. The advantage of ANNs is that they are robust and can be used to model complex linear and non-linear systems without making implicit assumptions. ANNs can be trained to forecast flow dynamics in a water distribution network. Such flow dynamics ...

  9. Radar Based Flow and Water Level Forecasting in Sewer Systems

    DEFF Research Database (Denmark)

    Thorndahl, Søren; Rasmussen, Michael R.; Grum, M.

    2009-01-01

    This paper describes the first radar based forecast of flow and/or water level in sewer systems in Denmark. The rainfall is successfully forecasted with a lead time of 1-2 hours, and flow/levels are forecasted an additional ½-1½ hours using models describing the behaviour of the sewer system. Bot...

  10. Free-Will and the Undesirability of Moral Education

    Science.gov (United States)

    Gordon, David

    1975-01-01

    This paper makes two arguments: (1) that education does not imply determinism; and (2) that if one takes the libertarian position with regard to the free-will/determinism issue, one is forced to the conclusion that moral education is undesirable. (RC)

  11. Flow improvers for water injection based on surfactants

    Energy Technology Data Exchange (ETDEWEB)

    Oskarsson, H.; Uneback, I.; Hellsten, M.

    2006-03-15

    In many cases it is desirable to increase the flow of injection water when an oil well deteriorates. It is very costly in offshore operation to lay down an additional water pipe to the injection site. Flow improvers for the injection water will thus be the most cost-effective way to increase the flow rate. During the last years water-soluble polymers have also been applied for this purpose. These drag-reducing polymers are however only slowly biodegraded which has been an incentive for the development of readily biodegradable surfactants as flow improvers for injection water. A combination of a zwitterionic and an anionic surfactant has been tested in a 5.5 inch, 700 m long flow loop containing sulphate brine with salinity similar to sea water. A drag reduction between 75 and 80% was achieved with 119 ppm in solution of the surfactant blend at an average velocity of 1.9 m/s and between 50 and 55% at 2.9 m/s. The surfactants in this formulation were also found to be readily biodegradable in sea water and low bio accumulating which means they have an improved environmental profile compared to the polymers used today. Due to the self-healing properties of the drag-reducing structures formed by surfactants, these may be added before the pump section - contrary to polymers which are permanently destroyed by high shear forces. (Author)

  12. An Experimental Study of Oil / Water Flow in Horizontal Pipes

    Energy Technology Data Exchange (ETDEWEB)

    Elseth, Geir

    2001-07-01

    The purpose of this thesis is to study the behaviour of the simultaneous flow of oil and water in horizontal pipes. In this connection, two test facilities are used. Both facilities have horizontal test sections with inner pipe diameters equal to 2 inches. The largest facility, called the model oil facility, has reservoirs of 1 m{sub 3} of each medium enabling flow rates as high as 30 m{sub 3}/h, which corresponds to mixture velocities as high as 3.35 m/s. The flow rates of oil and water can be varied individually producing different flow patterns according to variations in mixture velocity and input water cut. Two main classes of flows are seen, stratified and dispersed. In this facility, the main focus has been on stratified flows. Pressure drops and local phase fractions are measured for a large number of flow conditions. Among the instruments used are differential pressure transmitters and a traversing gamma densitometer, respectively. The flow patterns that appear are classified in flow pattern maps as functions of either mixture velocity and water cut or superficial velocities. From these experiments a smaller number of stratified flows are selected for studies of velocity and turbulence. A laser Doppler anemometer (LDA) is applied for these measurements in a transparent part of the test section. To be able to produce accurate measurements a partial refractive index matching procedure is used. The other facility, called the matched refractive index facility, has a 0.2 m{sub 3} reservoir enabling mainly dispersed flows. Mixture velocities range from 0.75 m/s to 3 m/s. The fluids in this facility are carefully selected to match the refractive index of the transparent part of the test section. A full refractive index matching procedure is carried out producing excellent optical conditions for velocity and turbulence studies by LDA. In addition, pressure drops and local phase fractions are measured. (author)

  13. Transition from slug to annular flow in horizontal air-water flow

    International Nuclear Information System (INIS)

    Reismann, J.; John, H.; Seeger, W.

    1981-11-01

    The transition from slug to annular flow in horizontal air-water and steam-water flow was investigated. Test sections of 50; 66.6 and 80 mm ID were used. The system pressure was 0.2 and 0.5 MPa in the air-water experiments and 2.5; 5; 7.5 and 10 MPa in the steam-water experiments. For flow pattern detection local impedance probes were used. This method was compared in a part of the experiments with differential pressure and gamma-beam measurements. The flow regime boundary is shifting strongly to smaller values of the superficial gas velocity with increasing pressure. Correlations from literature fit unsatisfactorily the experimental results. A new correlation is presented. (orig.) [de

  14. TRENDS IN VARIABILITY OF WATER FLOW OF TELEAJEN RIVER

    Directory of Open Access Journals (Sweden)

    N. JIPA

    2012-03-01

    Full Text Available TRENDS IN VARIABILITY OF WATER FLOW OF TELEAJEN RIVER. In the context of climate change at global and regional scale, this study intends to identify the trends in variability of the annual and monthly flow of Teleajen river. The study is based on processing the series of mean, maximum and minimum flows at Cheia and Moara Domnească hydrometric stations (these data were taken from the National Institute of Meteorology and Hydrology. The period of analysis is 1966-1998, statistical methods beeing mostly used, among which the Mann – Kendall test, that identifies the liniar trend and its statistic significance, comes into focus. The trends in the variability of water annual and monthly flows are highlighted. The results obtained show downward trends for the mean and maximum annual flows, and for the minimum water discharge, a downward trend for Cheia station and an upward trend for Moara Domnească station. Knowing the trends in the variability of the rivers’ flow is important empirically in view of taking adequate administration measures of the water resources and managment measures for the risks lead by extreme hidrologic events (floods, low-water, according to the possible identified changes.

  15. Water droplet condensation and evaporation in turbulent channel flow

    NARCIS (Netherlands)

    Russo, E; Kuerten, Johannes G.M.; van der Geld, C.W.M.; Geurts, Bernardus J.

    We propose a point-particle model for two-way coupling of water droplets dispersed in the turbulent flow of a carrier gas consisting of air and water vapour. We adopt an Euler–Lagrangian formulation based on conservation laws for the mass, momentum and energy of the continuous phase and on empirical

  16. Launch Environment Water Flow Simulations Using Smoothed Particle Hydrodynamics

    Science.gov (United States)

    Vu, Bruce T.; Berg, Jared J.; Harris, Michael F.; Crespo, Alejandro C.

    2015-01-01

    This paper describes the use of Smoothed Particle Hydrodynamics (SPH) to simulate the water flow from the rainbird nozzle system used in the sound suppression system during pad abort and nominal launch. The simulations help determine if water from rainbird nozzles will impinge on the rocket nozzles and other sensitive ground support elements.

  17. Continuum simulations of water flow past fullerene molecules

    DEFF Research Database (Denmark)

    Popadic, A.; Praprotnik, M.; Koumoutsakos, P.

    2015-01-01

    We present continuum simulations of water flow past fullerene molecules. The governing Navier-Stokes equations are complemented with the Navier slip boundary condition with a slip length that is extracted from related molecular dynamics simulations. We find that several quantities of interest...... as computed by the present model are in good agreement with results from atomistic and atomistic-continuum simulations at a fraction of the cost. We simulate the flow past a single fullerene and an array of fullerenes and demonstrate that such nanoscale flows can be computed efficiently by continuum flow...

  18. Energy Demodulation Algorithm for Flow Velocity Measurement of Oil-Gas-Water Three-Phase Flow

    Directory of Open Access Journals (Sweden)

    Yingwei Li

    2014-01-01

    Full Text Available Flow velocity measurement was an important research of oil-gas-water three-phase flow parameter measurements. In order to satisfy the increasing demands for flow detection technology, the paper presented a gas-liquid phase flow velocity measurement method which was based on energy demodulation algorithm combing with time delay estimation technology. First, a gas-liquid phase separation method of oil-gas-water three-phase flow based on energy demodulation algorithm and blind signal separation technology was proposed. The separation of oil-gas-water three-phase signals which were sampled by conductance sensor performed well, so the gas-phase signal and the liquid-phase signal were obtained. Second, we used the time delay estimation technology to get the delay time of gas-phase signals and liquid-phase signals, respectively, and the gas-phase velocity and the liquid-phase velocity were derived. At last, the experiment was performed at oil-gas-water three-phase flow loop, and the results indicated that the measurement errors met the need of velocity measurement. So it provided a feasible method for gas-liquid phase velocity measurement of the oil-gas-water three-phase flow.

  19. Instability of water-ice interface under turbulent flow

    Science.gov (United States)

    Izumi, Norihiro; Naito, Kensuke; Yokokawa, Miwa

    2015-04-01

    It is known that plane water-ice interface becomes unstable to evolve into a train of waves. The underside of ice formed on the water surface of rivers are often observed to be covered with ice ripples. Relatively steep channels which discharge melting water from glaciers are characterized by beds covered with a series of steps. Though the flowing agent inducing instability is not water but gas including water vapor, a similar train of steps have been recently observed on the Polar Ice Caps on Mars (Spiral Troughs). They are expected to be caused by the instability of water-ice interface induced by flowing fluid on ice. There have been some studies on this instability in terms of linear stability analysis. Recently, Caporeale and Ridolfi (2012) have proposed a complete linear stability analysis in the case of laminar flow, and found that plane water-ice interface is unstable in the range of sufficiently large Reynolds numbers, and that the important parameters are the Reynolds number, the slope angle, and the water surface temperature. However, the flow inducing instability on water-ice interface in the field should be in the turbulent regime. Extension of the analysis to the case of fully developed turbulent flow with larger Reynolds numbers is needed. We have performed a linear stability analysis on the instability of water-ice interface under turbulent flow conditions with the use of the Reynolds-averaged Navier-Stokes equations with the mixing length turbulent model, the continuity equation of flow, the diffusion/dispersion equation of heat, and the Stefan equation. In order to reproduce the accurate velocity distribution and the heat transfer in the vicinity of smooth walls with the use of the mixing length model, it is important to take into account of the rapid decrease in the mixing length in the viscous sublayer. We employ the Driest model (1956) to the formulation. In addition, as the thermal boundary condition at the water surface, we describe the

  20. Slug flooding in air-water countercurrent vertical flow

    International Nuclear Information System (INIS)

    Lee, Jae Young; Raman, Roger; Chang, Jen-Shih

    2000-01-01

    This paper is to study slug flooding in the vertical air-water countercurrent flow loop with a porous liquid injector in the upper plenum. More water penetration into the bottom plenum in slug flooding is observed than the annular flooding because the flow regime changes from the slug flow regime or periodic slug/annular flow regime to annular flow regime due to the hysteresis between the onset of flooding and the bridging film. Experiments were made tubes of 0.995 cm, 2.07 cm, and 5.08 cm in diameter. A mechanistic model for the slug flooding with the solitary wave whose height is four time of the mean film thickness is developed to produce relations of the critical liquid flow rate and the mean film thickness. After fitting the critical liquid flow rate with the experimental data as a function of the Bond number, the gas flow rate for the slug flooding is obtained by substituting the critical liquid flow rate to the annular flooding criteria. The present experimental data evaluate the slug flooding condition developed here by substituting the correlations for mean film thickness models in the literature. The best prediction was made by the correlation for the mean film thickness of the present study which is same as Feind's correlation multiplied by 1.35. (author)

  1. One-Water Hydrologic Flow Model (MODFLOW-OWHM)

    Science.gov (United States)

    Hanson, Randall T.; Boyce, Scott E.; Schmid, Wolfgang; Hughes, Joseph D.; Mehl, Steffen W.; Leake, Stanley A.; Maddock, Thomas; Niswonger, Richard G.

    2014-01-01

    The One-Water Hydrologic Flow Model (MF-OWHM) is a MODFLOW-based integrated hydrologic flow model (IHM) that is the most complete version, to date, of the MODFLOW family of hydrologic simulators needed for the analysis of a broad range of conjunctive-use issues. Conjunctive use is the combined use of groundwater and surface water. MF-OWHM allows the simulation, analysis, and management of nearly all components of human and natural water movement and use in a physically-based supply-and-demand framework. MF-OWHM is based on the Farm Process for MODFLOW-2005 (MF-FMP2) combined with Local Grid Refinement (LGR) for embedded models to allow use of the Farm Process (FMP) and Streamflow Routing (SFR) within embedded grids. MF-OWHM also includes new features such as the Surface-water Routing Process (SWR), Seawater Intrusion (SWI), and Riparian Evapotrasnpiration (RIP-ET), and new solvers such as Newton-Raphson (NWT) and nonlinear preconditioned conjugate gradient (PCGN). This IHM also includes new connectivities to expand the linkages for deformation-, flow-, and head-dependent flows. Deformation-dependent flows are simulated through the optional linkage to simulated land subsidence with a vertically deforming mesh. Flow-dependent flows now include linkages between the new SWR with SFR and FMP, as well as connectivity with embedded models for SFR and FMP through LGR. Head-dependent flows now include a modified Hydrologic Flow Barrier Package (HFB) that allows optional transient HFB capabilities, and the flow between any two layers that are adjacent along a depositional or erosional boundary or displaced along a fault. MF-OWHM represents a complete operational hydrologic model that fully links the movement and use of groundwater, surface water, and imported water for consumption by irrigated agriculture, but also of water used in urban areas and by natural vegetation. Supply and demand components of water use are analyzed under demand-driven and supply

  2. Nocturnal reverse flow in water-in-glass evacuated tube solar water heaters

    International Nuclear Information System (INIS)

    Tang, Runsheng; Yang, Yuqin

    2014-01-01

    Highlights: • Performance of water-in-glass evacuated tube solar water heaters (SWH) at night was studied. • Experimental measurements showed that reverse flow occurred in SWHs at night. • Reverse flow in SWHs was very high but the heat loss due to reverse flow was very low. • Reverse flow seemed not sensitive to atmospheric clearness but sensitive to collector tilt-angle. - Abstract: In this work, the thermal performance of water-in-glass evacuated tube solar water heaters (SWH) at nights was experimentally investigated. Measurements at nights showed that the water temperature in solar tubes was always lower than that in the water tank but higher than the ambient air temperature and T exp , the temperature of water inside tubes predicted in the case of the water in tubes being naturally cooled without reverse flow. This signified that the reverse flow in the system occurred at nights, making the water in solar tubes higher than T exp . It is found that the reverse flow rate in the SWH, estimated based on temperature measurements of water in solar tubes, seemed not sensitive to the atmospheric clearness but sensitive to the collector tilt-angle, the larger the tilt-angle of the collector, the higher the reverse flow rate. Experimental results also showed that, the reverse flow in the SWH was much higher as compared to that in a thermosyphonic domestic solar water heater with flat-plate collectors, but the heat loss from collectors to the air due to reverse flow in SWHs was very small and only took about 8–10% of total heat loss of systems

  3. Operation condition for continuous anti-solvent crystallization of CBZ-SAC cocrystal considering deposition risk of undesired crystals

    Science.gov (United States)

    Nishimaru, Momoko; Nakasa, Miku; Kudo, Shoji; Takiyama, Hiroshi

    2017-07-01

    Crystallization operation of cocrystal production has deposition risk of undesired crystals. Simultaneously, continuous manufacturing processes are focused on. In this study, conditions for continuous cocrystallization considering risk reduction of undesired crystals deposition were investigated on the view point of thermodynamics and kinetics. The anti-solvent cocrystallization was carried out in four-component system of carbamazepine, saccharin, methanol and water. From the preliminary batch experiment, the relationships among undesired crystal deposition, solution composition decided by mixing ratio of solutions, and residence time for the crystals were considered, and then the conditions of continuous experiment were decided. Under these conditions, the continuous experiment was carried out. The XRD patterns of obtained crystals in the continuous experiment showed that desired cocrystals were obtained without undesired crystals. This experimental result was evaluated by using multi-component phase diagrams from the view point of the operation point's movement. From the evaluation, it was found that there is a certain operation condition which the operation point is fixed with time in the specific domain without the deposition risk of undesired single component crystals. It means the possibility of continuous production of cocrystals without deposition risk of undesired crystals was confirmed by using multi-component phase diagrams.

  4. Water flow experiments and analyses on the cross-flow type mercury target model with the flow guide plates

    CERN Document Server

    Haga, K; Kaminaga, M; Hino, R

    2001-01-01

    A mercury target is used in the spallation neutron source driven by a high-intensity proton accelerator. In this study, the effectiveness of the cross-flow type mercury target structure was evaluated experimentally and analytically. Prior to the experiment, the mercury flow field and the temperature distribution in the target container were analyzed assuming a proton beam energy and power of 1.5 GeV and 5 MW, respectively, and the feasibility of the cross-flow type target was evaluated. Then the average water flow velocity field in the target mock-up model, which was fabricated from Plexiglass for a water experiment, was measured at room temperature using the PIV technique. Water flow analyses were conducted and the analytical results were compared with the experimental results. The experimental results showed that the cross-flow could be realized in most of the proton beam path area and the analytical result of the water flow velocity field showed good correspondence to the experimental results in the case w...

  5. Flow film boiling heat transfer in water and Freon-113

    International Nuclear Information System (INIS)

    Liu, Qiusheng; Shiotsu, Masahiro; Sakurai, Akira

    2002-01-01

    Experimental apparatus and method for film boiling heat transfer measurement on a horizontal cylinder in forced flow of water and Freon-113 under pressurized and subcooled conditions were developed. The experiments of film boiling heat transfer from single horizontal cylinders with diameters ranging from 0.7 to 5 mm in saturated and subcooled water and Freon-113 flowing upward perpendicular to the cylinders were carried out for the flow velocities ranging from 0 to 1 m/s under system pressures ranging from 100 to 500 kPa. Liquid subcoolings ranged from 0 to 50 K, and the cylinder surface superheats were raised up to 800 K for water and 400 K for Freon-113. The film boiling heat transfer coefficients obtained were depended on surface superheats, flow velocities, liquid subcoolings, system pressures and cylinder diameters. The effects of these parameters were systematically investigated under wider ranges of experimental conditions. It was found that the heat transfer coefficients are higher for higher flow velocities, subcoolings, system pressures, and for smaller cylinder diameters. The observation results of film boiling phenomena were obtained by a high-speed video camera. A new correlation for subcooled flow film boiling heat transfer was derived by modifying authors' correlation for saturated flow film boiling heat transfer with authors' experimental data under wide subcooled conditions. (author)

  6. Effect of Water Flows on Ship Traffic in Narrow Water Channels Based on Cellular Automata

    Directory of Open Access Journals (Sweden)

    Hu Hongtao

    2017-11-01

    Full Text Available In narrow water channels, ship traffic may be affected by water flows and ship interactions. Studying their effects can help maritime authorities to establish appropriate management strategies. In this study, a two-lane cellular automation model is proposed. Further, the behavior of ship traffic is analyzed by setting different water flow velocities and considering ship interactions. Numerical experiment results show that the ship traffic density-flux relation is significantly different from the results obtained by classical models. Furthermore, due to ship interactions, the ship lane-change rate is influenced by the water flow to a certain degree.

  7. Nitrogen transformations in wetlands: Effects of water flow patterns

    Energy Technology Data Exchange (ETDEWEB)

    Davidsson, T.

    1997-11-01

    In this thesis, I have studied nitrogen turnover processes in water meadows. A water meadow is a wetland where water infiltrates through the soil of a grassland field. It is hypothesized that infiltration of water through the soil matrix promotes nutrient transformations compared to surface flow of water, by increasing the contact between water, nutrients, soil organic matter and bacteria. I have studied how the balance between nitrogen removal (denitrification, assimilative uptake, adsorption) and release (mineralization, desorption) processes are affected by water flow characteristics. Mass balance studies and direct denitrification measurements at two field sites showed that, although denitrification was high, net nitrogen removal in the water meadows was poor. This was due to release of ammonium and dissolved organic nitrogen (DON) from the soils. In laboratory studies, using {sup 15}N isotope techniques, I have shown that nitrogen turnover is considerably affected by hydrological conditions and by soil type. Infiltration increased virtually all the nitrogen processes, due to deeper penetration of nitrate and oxygen, and extended zones of turnover processes. On the contrary, soils and sediments with surface water flow, diffusion is the main transfer mechanism. The relation between release and removal processes sometimes resulted in shifts towards net nitrogen production. This occurred in infiltration treatments when ammonium efflux was high in relation to denitrification. It was concluded that ammonium and DON was of soil origin and hence not a product of dissimilatory nitrate reduction to ammonium. Both denitrification potential and mineralization rates were higher in peaty than in sandy soil. Vertical or horizontal subsurface flow is substantial in many wetland types, such as riparian zones, tidal salt marshes, fens, root-zone systems and water meadows. Moreover, any environment where aquatic and terrestrial ecosystems meet, and where water level fluctuates

  8. Calculating the evaporated water flow in a wet cooling tower

    International Nuclear Information System (INIS)

    Grange, J.L.

    1994-04-01

    On a cooling tower, it is necessary to determine the evaporated water flow in order to estimate the water consumption with a good accuracy according to the atmospheric conditions, and in order to know the characteristics of the plume. The evaporated flow is small compared to the circulating flow. A direct measurement is very inaccurate and cannot be used. Only calculation can give a satisfactory valuation. The two usable theories are the Merkel's one in which there are some simplifying assumptions, and the Poppe's one which is more exact. Both theories are used in the numerical code TEFERI which has been developed and is run by Electricite de France. The results obtained by each method are compared and validated by measurements made in the hot air of a cooling tower. The consequences of each hypothesis of Merkel's theory are discussed. This theory does not give the liquid water content in the plume and it under-estimates the evaporated flow all the lower the ambient temperature is. On the other hand, the Poppe's method agrees very closely with the measurements as well for the evaporated flow than for the liquid water concentration. This method is used to establish the specific consumption curves of the great nuclear plants cooling towers as well as to calculate the emission of liquid water drops in the plumes. (author). 11 refs., 9 figs

  9. Effect of water and air flow on concentric tubular solar water desalting system

    International Nuclear Information System (INIS)

    Arunkumar, T.; Jayaprakash, R.; Ahsan, Amimul; Denkenberger, D.; Okundamiya, M.S.

    2013-01-01

    Highlights: ► We optimized the augmentation of condense by enhanced desalination methodology. ► We measured ambient together with solar radiation intensity. ► The effect of cooling air and water flowing over the cover was studied. -- Abstract: This work reports an innovative design of tubular solar still with a rectangular basin for water desalination with flowing water and air over the cover. The daily distillate output of the system is increased by lowering the temperature of water flowing over it (top cover cooling arrangement). The fresh water production performance of this new still is observed in Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore (11° North, 77° East), India. The water production rate with no cooling flow was 2050 ml/day (410 ml/trough). However, with cooling air flow, production increased to 3050 ml/day, and with cooling water flow, it further increased to 5000 ml/day. Despite the increased cost of the water cooling system, the increased output resulted in the cost of distilled water being cut in roughly half. Diurnal variations of a few important parameters are observed during field experiments such as water temperature, cover temperature, air temperature, ambient temperature and distillate output.

  10. Experimental measurements of the cavitating flow after horizontal water entry

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Thang Tat; Thai, Nguyen Quang; Phuong, Truong Thi [Institute of Mechanics (IMECH), Vietnam Academy of Science and Technology (VAST), 264—Doi Can, Ba Dinh, Hanoi (Viet Nam); Hai, Duong Ngoc, E-mail: ntthang@imech.vast.vn, E-mail: dnhai@vast.vn, E-mail: nqthai@imech.vast.vn, E-mail: ttphuong@imech.vast.vn [Graduate University of Science and Technology (GUST), VAST, 18—Hoang Quoc Viet, Cau Giay, Hanoi (Viet Nam)

    2017-10-15

    Water-entry cavitating flow is of considerable importance in underwater high-speed applications. That is because of the drag-reduction effect that concerns the presence of a cavity around moving objects. Though the study of the flow has long been carried out, little data are documented in literature so far. Besides, currently, in the case of unsteady flow, experimental measurements of some flow parameters such as the cavity pressure still encounter difficulties. Hence continuing research efforts are of important significance. The objective of this study is to investigate experimentally the unsteady cavitating flow after the horizontal water entry of projectiles. An experimental apparatus has been developed. Qualitative and quantitative optical visualizations of the flow have been carried out by using high-speed videography. Digital image processing has been applied to analyzing the recorded flow images. Based on the known correlations between the ellipsoidal super-cavity’s size and the corresponding cavitation number, the cavity pressure has been measured by utilizing the data of image processing. A comparison between the partial- and super-cavitating flow regimes is reported. The received results can be useful for the design of high-speed underwater projectiles. (paper)

  11. Anthropogenic Water Uses and River Flow Regime Alterations by Dams

    Science.gov (United States)

    Ferrazzi, M.; Botter, G.

    2017-12-01

    Dams and impoundments have been designed to reconcile the systematic conflict between patterns of anthropogenic water uses and the temporal variability of river flows. Over the past seven decades, population growth and economic development led to a marked increase in the number of these water infrastructures, so that unregulated free-flowing rivers are now rare in developed countries and alterations of the hydrologic cycle at global scale have to be properly considered and characterized. Therefore, improving our understanding of the influence of dams and reservoirs on hydrologic regimes is going to play a key role in water planning and management. In this study, a physically based analytic approach is combined to extensive hydrologic data to investigate natural flow regime alterations downstream of dams in the Central-Eastern United States. These representative case studies span a wide range of different uses, including flood control, water supply and hydropower production. Our analysis reveals that the most evident effects of flood control through dams is a decrease in the intra-seasonal variability of flows, whose extent is controlled by the ratio between the storage capacity for flood control and the average incoming streamflow. Conversely, reservoirs used for water supply lead to an increase of daily streamflow variability and an enhanced inter-catchment heterogeneity. Over the last decades, the supply of fresh water required to sustain human populations has become a major concern at global scale. Accordingly, the number of reservoirs devoted to water supply increased by 50% in the US. This pattern foreshadows a possible shift in the cumulative effect of dams on river flow regimes in terms of inter-catchment homogenization and intra-annual flow variability.

  12. Theoretical investigation of flow regime for boiling water two-phase flow in horizontal rectangular narrow channels

    International Nuclear Information System (INIS)

    Zhang Chunwei; Qiu Suizheng; Yan Mingyu; Wang Bulei; Nie Changhua

    2005-01-01

    The flow regime transition criteria for the boiling water two-phase flow in horizontal rectangular narrow channels (1 x 20 mm, 2 x 20 mm) were theoretically explored. The discernible flow patterns were bubble, intermittent slug, churn, annular and steam-water separation flow. By using two-fluid model, equations of conservation of momentum were established for the two-phase flow. New flow-regime criteria were obtained and agreed well with the experiment data. (authors)

  13. A two stage data envelopment analysis model with undesirable output

    Science.gov (United States)

    Shariff Adli Aminuddin, Adam; Izzati Jaini, Nur; Mat Kasim, Maznah; Nawawi, Mohd Kamal Mohd

    2017-09-01

    The dependent relationship among the decision making units (DMU) is usually assumed to be non-existent in the development of Data Envelopment Analysis (DEA) model. The dependency can be represented by the multi-stage DEA model, where the outputs from the precedent stage will be the inputs for the latter stage. The multi-stage DEA model evaluate both the efficiency score for each stages and the overall efficiency of the whole process. The existing multi stage DEA models do not focus on the integration with the undesirable output, in which the higher input will generate lower output unlike the normal desirable output. This research attempts to address the inclusion of such undesirable output and investigate the theoretical implication and potential application towards the development of multi-stage DEA model.

  14. A Case of Undesired Bleb Developed After Penetrating Injury

    Directory of Open Access Journals (Sweden)

    Cem Ozgonul

    2014-03-01

    Full Text Available Eighty-year-old male patient was admitted to our policlinic with stinging, burning and itching in both eyes. Ophthalmological examination revealed avascular undesired bleb that releated with anterior chamber at 2-3 hour quadrant nasal limbus with the surrounding corneal and conjunctival epithelium was vascularized and the dimension was 3x3x3 mm. Towards these findings, we questioned the patient again and we found that, 40 years ago, a broken part of the shaving razor had injured his eye. After penetrating injury of the eye, because of the sutured wound leakage, undesired bleb formations can be seen. We suggest that kind of patient shold be followed up to prevent late complications of penetrating injury.

  15. Worry and perceived threat of proximal and distal undesirable outcomes.

    Science.gov (United States)

    Bredemeier, Keith; Berenbaum, Howard; Spielberg, Jeffrey M

    2012-04-01

    Individuals who are prone to worry tend to overestimate the likelihoods and costs of future undesirable outcomes. However, it is unclear whether these relations vary as a function of the timeframe of the event in question. In the present study, 342 undergraduate students completed a self-report measure of worry and rated the perceived probabilities and costs of 40 undesirable outcomes. Specifically, each participant estimated the probability that each of these outcomes would occur within three different timeframes: the next month, the next year, and the next 10 years. We found that the strength of the association between worry and probability estimates was strongest for the most proximal timeframe. Probability estimates were more strongly associated with worry for participants with elevated cost estimates, and this interactive effect was strongest for the most distal timeframe. Implications of these findings for understanding the etiology and treatment of excessive worry are discussed. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Ductile flow by water-assisted cataclasis

    Science.gov (United States)

    den Brok, Bas

    2003-04-01

    In the presence of water otherwise brittle materials may deform macroscopically ductile by water-assisted cataclastic creep. This is possible as long as (i) solubility is high enough, so that stress-corrosion can occur, and (ii) local stress is low enough, to that fracturing remains subcritical. Water-assisted cataclastic creep (WACC) may play an important role in the middle and lower continental crust where mineral solubilities are high and stresses low. WACC is a poorly understood deformation process. Experiments were performed on very soluble brittle salts (Na-chlorate; K-alum) to study microstructure development by WACC. The experiments were carried out at room temperature and atmospheric pressure in a small see-through vessel. In this way the cataclastic deformation process could be studied "in-situ" under the microscope. Crystals were loaded in the presence of saturated salt solution. It appeared that originally straight mineral surfaces were instable when kept under stress. Grooves (or channels) slowly developed in the surface by local dissolution. These grooves behave like so-called Grinfeld instabilities. They develop because the energy of a grooved surface under stress is lower than the energy of a straight surface under stress. The grooves may deepen and turn into subcritical cracks when local stress further increases. These cracks propagate slowly. They propagate parallel to sigma1 but also at an angle and even perpendicular to sigma1, often following crystallographically controlled directions. The fractures mostly change direction while propagating, locally making turns of more than 180 degrees. Irregular fracture fragments thus develop. The fractures may migrate sideways (as with grain bounday migration) probably by solution-redeposition driven by differences in stress between both sides of the fracture. Thus the shape of the fragments changes. The size of the fracture fragments seems to be controlled by the distance of the grooves, which decreases

  17. Unstable Pore-Water Flow in Intertidal Wetlands

    Science.gov (United States)

    Barry, D. A.; Shen, C.; Li, L.

    2014-12-01

    Salt marshes are important intertidal wetlands strongly influenced by interactions between surface water and groundwater. Bordered by coastal water, the marsh system undergoes cycles of inundation and exposure driven by the tide. This leads to dynamic, complex pore-water flow and solute transport in the marsh soil. Pore-water circulations occur over vastly different spatial and temporal scales with strong link to the marsh topography. These circulations control solute transport between the marsh soil and the tidal creek, and ultimately affect the overall nutrient exchange between the marsh and coastal water. The pore-water flows also dictate the soil condition, particularly aeration, which influences the marsh plant growth. Numerous studies have been carried out to examine the pore-water flow process in the marsh soil driven by tides, focusing on stable flow with the assumption of homogeneity in soil and fluid properties. This assumption, however, is questionable given the actual inhomogeneous conditions in the field. For example, the salinity of surface water in the tidal creek varies temporally and spatially due to the influence of rainfall and evapotranspiration as well as the freshwater input from upland areas to the estuary, creating density gradients across the marsh surface and within the marsh soil. Many marshes possess soil stratigraphy with low-permeability mud typically overlying high-permeability sandy deposits. Macropores such as crab burrows are commonly distributed in salt marsh sediments. All these conditions are prone to the development of non-uniform, unstable preferential pore-water flow in the marsh soil, for example, funnelling and fingering. Here we present results from laboratory experiments and numerical simulations to explore such unstable flow. In particular, the analysis aims to address how the unstable flow modifies patterns of local pore-water movement and solute transport, as well as the overall exchange between the marsh soil and

  18. Do water-saving technologies improve environmental flows?

    Science.gov (United States)

    Batchelor, Charles; Reddy, V. Ratna; Linstead, Conor; Dhar, Murli; Roy, Sumit; May, Rebecca

    2014-10-01

    Water saving and conservation technologies (WCTs) have been promoted widely in India as a practical means of improving the water use efficiency and freeing up water for other uses (e.g. for maintaining environmental flows in river systems). However, there is increasing evidence that, somewhat paradoxically, WCTs often contribute to intensification of water use by irrigated and rainfed farming systems. This occurs when: (1) Increased crop yields are coupled with increased consumptive water use and/or (2) Improved efficiency, productivity and profitability encourages farmers to increase the area cropped and/or to adopt multiple cropping systems. In both cases, the net effect is an increase in annual evapotranspiration that, particularly in areas of increasing water scarcity, can have the trade-off of reduced environmental flows. Recognition is also increasing that the claimed water savings of many WCTs may have been overstated. The root cause of this problem lies in confusion over what constitutes real water saving at the system or basin scales. The simple fact is that some of the water that is claimed to be ‘saved’ by WCTs would have percolated into the groundwater from where it can be and often is accessed and reused. Similarly, some of the “saved” runoff can be used downstream by, for example, farmers or freshwater ecosystems. This paper concludes that, particularly in areas facing increasing water scarcity, environmental flows will only be restored and maintained if they are given explicit (rather than theoretical or notional) attention. With this in mind, a simple methodology is proposed for deciding when and where WCTs may have detrimental impacts on environmental flows.

  19. Cycles of undesirable substances in the food chain

    International Nuclear Information System (INIS)

    2012-01-01

    The working group ''Carry over of undesirable substances in animal feed'' at the Federal Ministry of Food, Agriculture and Forestry (BMELV) in cooperation with the Institute of Animal Nutrition of the Friedrich-Loeffler-Institute (FLI) performed on 27 and 28 October 2011 in Braunschweig a workshop on ''cycles of undesirable substances in Food Chain ''. The aim of the workshop was to present the latest findings of research and Carry over Recommendations of the Carry over - Working Group on undesirable substances in feed and production processes of the feed industry, to evaluate and discuss about this with representatives from science, business and management and to work out the further research and action need. The focus of the considerations were the pathways, the carry over and the Exposure to dioxins and other halogenated hydrocarbons, the effects of Mycotoxins in feed and starting points for preventive measures, the soil contamination and the exposure of humans and animals by cadmium and case studies on Nitrite in feed, antibiotics in plants and residues of pesticides and radionuclides in feed. Furthermore the risks associated with specified manufacturing processes of feed are considered, especially the used materials that come into contact with animal feed, and the risks from nanotechnology. [de

  20. How much water flows? Examining water allocations using a mobile decision lab

    Science.gov (United States)

    Strickert, G. E.; Gober, P.; Bradford, L. E.; Phillips, P.; Ross, J.

    2016-12-01

    Management of freshwater resources is a complex and multifaceted issues. Big challenges like scarcity, conflicts over water use and access, and ecosystem degradation are widespread around the world. These issues reflects ineffective past practices and signals the need for a fundamental change. Previous actions to mitigate these problems have been incremental rather than innovative, in part because of inherent conservatism in the water management community and an inability to experiment with water allocations in a safe environment. The influence of transboundary water policies was tested using a mobile decision lab which examined three theory areas: limited territorial sovereignty, absolute territorial sovereignty, and shared risk. The experiment allowed people engaged in the water sector to allocate incoming flows to different sectors: agriculture, municipal, industrial and environmental flows in two flow scenarios; slight shortage and extreme water shortage, and to pass on the remaining water to downstream regions. Mandatory sharing 50% of the natural flows between provinces (i.e. limited territorial sovereignty) achieved the most equitable allocation based on water units and points across the three regions. When there were no allocation rules (i.e. absolute territorial sovereignty) the downstream region received significantly less water (e.g. 8-11%. p affect on the amount of water flowing through the region. It is also notable that most participants sought a trade-off of water allocations, minimizing the allocations to agriculture and industry and prioritizing the municipal sector particularity under the severe drought scenario.

  1. Interfacial heat transfer in countercurrent flows of steam and water

    International Nuclear Information System (INIS)

    Megahed, M.M.

    1987-04-01

    A study was conducted to examine the departure from equilibrium conditions with respect to direct contact condensation. A simple analytical model, which used an equilibrium factor, K, was derived. The model was structured to represent the physical dimensions of a nuclear reactor downcomer annulus, water subcooling, wall temperature, and water flow rate. In a two step process the model was first used to isolate the average interfacial heat transfer coefficient from vertical countercurrent steam/water data of Cook et al., with the aid of a Stanton number correlation. In the second step the model was assessed by regeneration of measured steam flow rates in the experiments by Cook et al., and an additional experiment of Kim. This report documents the analytical model, the derived Stanton number correlation, and the comparison of the calculated and measured steam flow rates by which the accuracy of the model was assessed

  2. How fast does water flow in carbon nanotubes?

    DEFF Research Database (Denmark)

    Kannam, Sridhar; Todd, Billy; Hansen, Jesper Schmidt

    2013-01-01

    The purpose of this paper is threefold. First, we review the existing literature on flow rates of water in carbon nanotubes. Data for the slip length which characterizes the flow rate are scattered over 5 orders of magnitude for nanotubes of diameter 0.81–10 nm. Second, we precisely compute...... the slip length using equilibrium molecular dynamics (EMD) simulations, from which the interfacial friction between water and carbon nanotubes can be found, and also via external field driven non-equilibrium molecular dynamics simulations (NEMD). We discuss some of the issues in simulation studies which...... and reliably extrapolate the results for the slip length to values of the field corresponding to experimentally accessible pressure gradients. Finally, we comment on several issues concerning water flow rates in carbon nanotubes which may lead to some future research directions in this area....

  3. Turbulent water flow over rough bed - part I

    Energy Technology Data Exchange (ETDEWEB)

    Ksiazek, Leszek; Bartnik, Wojciech; Rumian, Jacek; Zagorowski, Pawel, E-mail: rmksiaze@cyf-kr.edu.pl [Department of Hydraulic Engineering and Geotechnics, University of Agriculture in Krakow, Mickiewicza Avenue 24/28, 30-059 Krakow (Poland)

    2011-12-22

    Restitution of diadromic fish requires restoration of ecological continuity of watercourses, e.g. by building fish ladders. Directions for fish ladders require that ichthyofauna is granted accurate conditions of water flow. To describe them, average values are used, that do not convey e.g. turbulence intensity or its spatial differentiation. The paper presents results of research on the turbulent water flow over the rough bed. The measurements were carried out with high sampling frequency probe for three velocity components. Bed configuration, distribution of average velocities and turbulence intensity were defined. The range of bed influence for the discussed water flow conditions was ascertained to reach the maximum of about 0.25 of height and decline at 0.35. The lowest turbulence and relatively lowest velocities near the bed may promote successive stages of ichthyofauna development.

  4. Device for preventing cooling water from flowing out of reactor

    International Nuclear Information System (INIS)

    Chinen, Masanori; Kotani, Koichi; Murase, Michio.

    1976-01-01

    Object: To provide emergency cooling system, which can prevent cooling water bearing radioactivity from flowing to the outside of the reactor at the time of breakage of feedwater pipe, thus eliminating the possibility of exposure of the fuel rod to provide high reliability and also reducing the possibility of causing radioactive pollution. Structure: The device for preventing cooling water from flowing out from the reactor features a jet nozzle inserted in a feedwater pipe adjacent to the inlet or outlet thereof immediately before the reactor container. The nozzle outlet is provided in the vicinity of the reactor wall and in a direction opposite to the direction of out-flow, and water supplied from a high pressure pump is jetted from it. (Nakamura, S.)

  5. Water: The Flow of Women's Work. Water in Africa.

    Science.gov (United States)

    Cohen, Amy

    The Water in Africa Project was realized over a 2-year period by a team of Peace Corps volunteers, World Wise Schools (WWS) classroom teachers, and WWS staff members. As part of an expanded, detailed design, resources were collected from over 90 volunteers serving in African countries, photos and stories were prepared, and standards-based learning…

  6. Flow Accelerated Corrosion: Effect of Water Chemistry and Database Construction

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Hee; Kim, Kyung Mo; Lee, Gyeong Geun; Kim, Dong Jin [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    Flow accelerated corrosion (FAC) of carbon steel piping in pressurized water reactors (PWRs) has been a major issue in nuclear industry. Severe accidents at Surry Unit 2 in 1986 and Mihama Unit 3 in 2004 initiated the world wide interest in this area. FAC is a dissolution process of the protective oxide layer on carbon steel or low-alloy steel when these parts are exposed to flowing water (single-phase) or wet steam (two-phase). In a single-phase flow, a scalloped, wavy, or orange peel and in a two-phase flow, tiger striping is observed, respectively. FAC is affected by many parameters, like material composition, pH, dissolved oxygen (DO), flow velocity, system pressure, and steam quality. This paper describes the water chemistry factors influencing on FAC and the database is then constructed using literature data. In order to minimize FAC in NPPs, the optimal method is to control water chemistry parameters. However, quantitative data about FAC have not been published for proprietary reason even though qualitative behaviors of FAC have been well understood. A database was constructed using experimental data in literature. Accurate statistical analysis will be performed using this database to identify the relationship between the FAC rate and test environment.

  7. Critical heat flux and flow pattern for water flow in annular geometry

    International Nuclear Information System (INIS)

    Park, J.-W.; Baek, W.-P.; Chang, S.H.

    1997-01-01

    An experimental study on critical heat flux (CHF) and two-phase flow visualization has been performed for water flow in internally-heated, vertical, concentric annuli under near atmospheric pressure. Tests have been done under stable forced-circulation, upward and downward flow conditions with three test sections of relatively large gap widths (heated length = 0.6 m, inner diameter 19 mm, outer diameter = 29, 35 and 51 mm). The outer wall of the test section was made up of the transparent Pyrex tube to allow the observation of flow patterns near the CHF occurrence. The CHF mechanism was changed in the order of flooding, churn-to-annular flow transition and local dryout under a large bubble in churn flow as the flow rate was increased from zero to higher values. Observed parametric trends are consistent with the previous understanding except that the CHF for downward flow is considerably lower than that for the upward flow. In addition to the experiment, selected CHF correlations for annuli are assessed based on 1156 experimental data from various sources. The Doerffer et al. (1994); Barnett (1966); Jannsen and Kervinen (1963); Levitan and Lantsman (1977) correlations show reasonable predictions for wide parameter ranges, among which the Doerffer et al. (1994) correlation shows the widest parameter ranges and a possibility of further improvement. However, there is no correlation predicting the low-pressure, low-flow CHF satisfactorily. (orig.)

  8. The virtual water content of major grain crops and virtual water flows between regions in China.

    Science.gov (United States)

    Sun, Shi-Kun; Wu, Pu-Te; Wang, Yu-Bao; Zhao, Xi-Ning

    2013-04-01

    The disproportionate distribution of arable land and water resources has become a bottleneck for guaranteeing food security in China. Virtual water and virtual water trade theory have provided a potential solution to improve water resources management in agriculture and alleviate water crises in water-scarce regions. The present study evaluates the green and blue virtual water content of wheat, maize and rice at the regional scale in China. It then assesses the water-saving benefits of virtual water flows related to the transfer of the three crops between regions. The national average virtual water content of wheat, maize and rice were 1071 m(3) per ton (50.98% green water, 49.02% blue water ), 830 m(3) per ton (76.27% green water, 23.73% blue water) and 1294 m(3) per ton (61.90% green water, 38.10% blue water), respectively. With the regional transfer of wheat, maize and rice, virtual water flows reached 30.08 Gm(3) (59.91% green water, 40.09% blue water). Meanwhile, China saved 11.47 Gm(3) green water, while it consumed 7.84 Gm(3) more blue water than with a no-grain transfer scenario in 2009. In order to guarantee food security in China, the government should improve water productivity (reduce virtual water content of crops) during the grain production process. Meanwhile, under the preconditions of economic feasibility and land-water resources availability, China should guarantee the grain-sown area in southern regions for taking full advantage of green water resources and to alleviate the pressure on water resources. © 2012 Society of Chemical Industry.

  9. Sodium-water reaction product flow system

    Energy Technology Data Exchange (ETDEWEB)

    Shirataki, K; Wada, H

    1978-11-18

    Purpose: To provide the subject equipments wherein thermal insulating layers which neither exfoliate nor react by the impact due to high temperature sodium and hydrogen gas and are used for mitigating the thermal impact are provided on the inner surfaces of the emission system equipments, thereby preventing the destruction of the emission system equipments. Constitution: Thermal insulating layers are formed on the inner surfaces of sodium-water reaction product emission system equipments, that is, the inner surface of the emission system pipeline, that of the accommodation vessel and the surface of the cyclone separator, by film treatment, coating or heat resisting coating, and these surfaces are covered with the layers. Each of the layers is made of a material which does not cause a rapid reaction with high temperature sodium or hydrogen gas nor exfoliates and is withstandable for several seconds in which the thermal impact of at least the emission system comes into question, and its thickness is more than one capable of securing the necessary thermal resistance computed by the thermal impact analysis of the emission system.

  10. Sodium-water reaction product flow system

    International Nuclear Information System (INIS)

    Shirataki, Koji; Wada, Hozumi.

    1978-01-01

    Purpose: To provide the subject equipments wherein thermal insulating layers which neither exfoliate nor react by the impact due to high temperature sodium and hydrogen gas and are used for mitigating the thermal impact are provided on the inner surfaces of the emission system equipments, thereby preventing the destruction of the emission system equipments. Constitution: Thermal insulating layers are formed on the inner surfaces of sodium-water reaction product emission system equipments, that is, the inner surface of the emission system pipeline, that of the accommodation vessel and the surface of the cyclone separator, by film treatment, coating or heat resisting coating, and these surfaces are covered with the layers. Each of the layers is made of a material which does not cause a rapid reaction with high temperature sodium or hydrogen gas nor exfoliates and is withstandable for several seconds in which the thermal impact of at least the emission system comes into question, and its thickness is more than one capable of securing the necessary thermal resistance computed by the thermal impact analysis of the emission system. (Yoshihara, H.)

  11. Supercritical water natural circulation flow stability experiment research

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Dongliang; Zhou, Tao; Li, Bing [North China Electric Power Univ., Beijing (China). School of Nuclear Science and Engineering; North China Electric Power Univ., Beijing (China). Inst. of Nuclear Thermalhydraulic Safety and Standardization; North China Electric Power Univ., Beijing (China). Beijing Key Lab. of Passive Safety Technology for Nuclear Energy; Huang, Yanping [Nuclear Power Institute of China, Chengdu (China). Science and Technology on Reactor System Design Technology Lab.

    2017-12-15

    The Thermal hydraulic characteristics of supercritical water natural circulation plays an important role in the safety of the Generation-IV supercritical water-cooled reactors. Hence it is crucial to conduct the natural circulation heat transfer experiment of supercritical water. The heat transfer characteristics have been studied under different system pressures in the natural circulation systems. Results show that the fluctuations in the subcritical flow rate (for natural circulation) is relatively small, as compared to the supercritical flow rate. By increasing the heating power, it is observed that the amplitude (and time period) of the fluctuation tends to become larger for the natural circulation of supercritical water. This tends to show the presence of flow instability in the supercritical water. It is possible to observe the flow instability phenomenon when the system pressure is suddenly reduced from the supercritical pressure state to the subcritical state. At the test outlet section, the temperature is prone to increase suddenly, whereas the blocking effect may be observed in the inlet section of the experiment.

  12. CFD Numerical Simulation of the Complex Turbulent Flow Field in an Axial-Flow Water Pump

    Directory of Open Access Journals (Sweden)

    Wan-You Li

    2014-09-01

    Full Text Available Further optimal design of an axial-flow water pump calls for a thorough recognition of the characteristics of the complex turbulent flow field in the pump, which is however extremely difficult to be measured using the up-to-date experimental techniques. In this study, a numerical simulation procedure based on computational fluid dynamics (CFD was elaborated in order to obtain the fully three-dimensional unsteady turbulent flow field in an axial-flow water pump. The shear stress transport (SST k-ω model was employed in the CFD calculation to study the unsteady internal flow of the axial-flow pump. Upon the numerical simulation results, the characteristics of the velocity field and pressure field inside the impeller region were discussed in detail. The established model procedure in this study may provide guidance to the numerical simulations of turbomachines during the design phase or the investigation of flow and pressure field characteristics and performance. The presented information can be of reference value in further optimal design of the axial-flow pump.

  13. Water flow and fin shape polymorphism in coral reef fishes.

    Science.gov (United States)

    Binning, Sandra A; Roche, Dominique G

    2015-03-01

    Water flow gradients have been linked to phenotypic differences and swimming performance across a variety of fish assemblages. However, the extent to which water motion shapes patterns of phenotypic divergence within species remains unknown. We tested the generality of the functional relationship between swimming morphology and water flow by exploring the extent of fin and body shape polymorphism in 12 widespread species from three families (Acanthuridae, Labridae, Pomacentridae) of pectoral-fin swimming (labriform) fishes living across localized wave exposure gradients. The pectoral fin shape of Labridae and Acanthuridae species was strongly related to wave exposure: individuals with more tapered, higher aspect ratio (AR) fins were found on windward reef crests, whereas individuals with rounder, lower AR fins were found on leeward, sheltered reefs. Three of seven Pomacentridae species showed similar trends, and pectoral fin shape was also strongly related to wave exposure in pomacentrids when fin aspect ratios of three species were compared across flow habitats at very small spatial scales (fish body fineless ratio across habitats or depths. Contrary to our predictions, there was no pattern relating species' abundances to polymorphism across habitats (i.e., abundance was not higher at sites where morphology is better adapted to the environment). This suggests that there are behavioral and/or physiological mechanisms enabling some species to persist across flow habitats in the absence of morphological differences. We suggest that functional relationships between swimming morphology and water flow not only structure species assemblages, but are yet another important variable contributing to phenotypic differences within species. The close links between fin shape polymorphism and local water flow conditions appear to be important for understanding species' distributions as well as patterns of diversification across environmental gradients.

  14. Liquid velocity in upward and downward air-water flows

    International Nuclear Information System (INIS)

    Sun Xiaodong; Paranjape, Sidharth; Kim, Seungjin; Ozar, Basar; Ishii, Mamoru

    2004-01-01

    Local characteristics of the liquid phase in upward and downward air-water two-phase flows were experimentally investigated in a 50.8-mm inner-diameter round pipe. An integral laser Doppler anemometry (LDA) system was used to measure the axial liquid velocity and its fluctuations. No effect of the flow direction on the liquid velocity radial profile was observed in single-phase liquid benchmark experiments. Local multi-sensor conductivity probes were used to measure the radial profiles of the bubble velocity and the void fraction. The measurement results in the upward and downward two-phase flows are compared and discussed. The results in the downward flow demonstrated that the presence of the bubbles tended to flatten the liquid velocity radial profile, and the maximum liquid velocity could occur off the pipe centerline, in particular at relatively low flow rates. However, the maximum liquid velocity always occurred at the pipe center in the upward flow. Also, noticeable turbulence enhancement due to the bubbles in the two-phase flows was observed in the current experimental flow conditions. Furthermore, the distribution parameter and the void-weighted area-averaged drift velocity were obtained based on the definitions

  15. Effect of Flood Water Diffuser on Flow Pattern of Water during Road Crossing

    Directory of Open Access Journals (Sweden)

    Abdul Ghani A.N.

    2014-03-01

    Full Text Available One of the methods to reduce the velocity of flood water flow across roads is to design obstacle objects as diffusers and place them alongside the road shoulder. The velocity reduction of water flow depends on the diffusion pattern of water. The pattern of diffused water depends on the design of the obstacle objects. The main purpose of this study is to investigate the design of obstacle objects and their water diffusing patterns and their capability to reduce the velocity of the flood water flow during road crossing. Variety of designs and orientation of the obstacle objects were tested in the environmental laboratory on a scale of 1:20. The results are classified into three distinguishable patterns of diffusion. Finally, two diffuser shapes and arrangements are recommended for further investigations in full scale or CFD model.

  16. Flow structure of steam-water mixed spray

    International Nuclear Information System (INIS)

    Sanada, Toshiyuki; Mitsuhashi, Yuki; Mizutani, Hiroya; Saito, Takayuki

    2010-01-01

    In this study, the flow structure of a steam-water mixed spray is studied both numerically and experimentally. The velocity and pressure profiles of single-phase flow are calculated using numerical methods. On the basis of the calculated flow fields, the droplet behavior is predicted by a one-way interaction model. This numerical analysis reveals that the droplets are accelerated even after they are sprayed from the nozzle. Experimentally, the mixed spray is observed using an ultra-high-speed video camera, and the velocity field is measured by using the oarticle image velocimetry (PIV) technique. Along with this PIV velocity field measurement, the velocities and diameters of droplets are measured by phase Doppler anemometry. Furthermore, the mixing process of steam and water and the atomization process of a liquid film are observed using a transparent nozzle. High-speed photography observations reveal that the flow inside the nozzle is annular flow and that most of the liquid film is atomized at the nozzle throat and nozzle outlet. Finally, the optimum mixing method for steam and water is determined.

  17. Flow structure of steam-water mixed spray

    Energy Technology Data Exchange (ETDEWEB)

    Sanada, Toshiyuki, E-mail: ttsanad@ipc.shizuoka.ac.j [Department of Mechanical Engineering, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8561, Shizuoka (Japan); Mitsuhashi, Yuki; Mizutani, Hiroya; Saito, Takayuki [Department of Mechanical Engineering, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8561, Shizuoka (Japan)

    2010-12-15

    In this study, the flow structure of a steam-water mixed spray is studied both numerically and experimentally. The velocity and pressure profiles of single-phase flow are calculated using numerical methods. On the basis of the calculated flow fields, the droplet behavior is predicted by a one-way interaction model. This numerical analysis reveals that the droplets are accelerated even after they are sprayed from the nozzle. Experimentally, the mixed spray is observed using an ultra-high-speed video camera, and the velocity field is measured by using the oarticle image velocimetry (PIV) technique. Along with this PIV velocity field measurement, the velocities and diameters of droplets are measured by phase Doppler anemometry. Furthermore, the mixing process of steam and water and the atomization process of a liquid film are observed using a transparent nozzle. High-speed photography observations reveal that the flow inside the nozzle is annular flow and that most of the liquid film is atomized at the nozzle throat and nozzle outlet. Finally, the optimum mixing method for steam and water is determined.

  18. Continuous Flow of Upper Labrador Sea Water around Cape Hatteras.

    Science.gov (United States)

    Andres, Magdalena; Muglia, Mike; Bahr, Frank; Bane, John

    2018-03-14

    Six velocity sections straddling Cape Hatteras show a deep counterflow rounding the Cape wedged beneath the poleward flowing Gulf Stream and the continental slope. This counterflow is likely the upper part of the equatorward-flowing Deep Western Boundary Current (DWBC). Hydrographic data suggest that the equatorward flow sampled by the shipboard 38 kHz ADCP comprises the Upper Labrador Sea Water (ULSW) layer and top of the Classical Labrador Sea Water (CLSW) layer. Continuous DWBC flow around the Cape implied by the closely-spaced velocity sections here is also corroborated by the trajectory of an Argo float. These findings contrast with previous studies based on floats and tracers in which the lightest DWBC constituents did not follow the boundary to cross under the Gulf Stream at Cape Hatteras but were diverted into the interior as the DWBC encountered the Gulf Stream in the crossover region. Additionally, our six quasi-synoptic velocity sections confirm that the Gulf Stream intensified markedly at that time as it approached the separation point and flowed into deeper waters. Downstream increases were observed not only in the poleward transport across the sections but also in the current's maximum speed.

  19. Two-phase flow in the upper plenum of a boiling water nuclear reactor

    International Nuclear Information System (INIS)

    Tinoco, Hernan

    2003-01-01

    The end part of the Emergency Core Spray System (ECSS) of the Boiling Water Reactors (BWRs) at Forsmark Nuclear Power Plant (NPP) is situated in the Upper Plenum. It consists of a pipe network equipped with water injection nozzles. In case of Lost-of-Coolant Accidents (LOCAs), the ECSS should maintain the core covered by water and, at the same time, rapidly cool and decompress the reactor by means of cold water injection. In similar reactors, some welds belonging to the ECSS support have, after a period of time, shown crack indications. Inspection, repair or replacement of these welds is time consuming and expensive. For this reason, it has now been decided to permanently remove the end part of the ECSS and to replace it by water injection in the Downcomer. However, this removal should not be accompanied by undesirable effects like an increase in the moisture of the steam used for operating the turbines. To investigate the effect of this removal on the steam moisture, a CFD analysis of the two-phase flow in the Upper Plenum of Unit 3, with and without ECSS, has been carried out by means of a two-phase Euler model in FLUENT 6.0. The inlet conditions are given by an analysis of the core kinetics and thermal hydraulics by mean of the POLCA-code. The outlet conditions, i. e. the steam separator pressure drops, are given by empirical correlations from the experiments carried out at the SNORRE facility. The predicted the mass flow-rates to each separator, together with empirical correlations for the moisture content of the steam leaving the separators and the steam dryer, indicate a slight decrease in the steam moisture when the ECSS is removed. Also, a minor decrease in pressure losses over the Upper Plenum is achieved with this removal. On the other hand, rounding the sharp edges of the inlet openings to the steam separators at the shroud cover may give a large reduction in pressure losses

  20. The Impact of Rhizosphere Processes on Water Flow and Root Water Uptake

    Science.gov (United States)

    Schwartz, Nimrod; Kroener, Eva; Carminati, Andrea; Javaux, Mathieu

    2015-04-01

    For many years, the rhizosphere, which is the zone of soil in the vicinity of the roots and which is influenced by the roots, is known as a unique soil environment with different physical, biological and chemical properties than those of the bulk soil. Indeed, in recent studies it has been shown that root exudate and especially mucilage alter the hydraulic properties of the soil, and that drying and wetting cycles of mucilage result in non-equilibrium water dynamics in the rhizosphere. While there are experimental evidences and simplified 1D model for those concepts, an integrated model that considers rhizosphere processes with a detailed model for water and roots flow is absent. Therefore, the objective of this work is to develop a 3D physical model of water flow in the soil-plant continuum that take in consideration root architecture and rhizosphere specific properties. Ultimately, this model will enhance our understanding on the impact of processes occurring in the rhizosphere on water flow and root water uptake. To achieve this objective, we coupled R-SWMS, a detailed 3D model for water flow in soil and root system (Javaux et al 2008), with the rhizosphere model developed by Kroener et al (2014). In the new Rhizo-RSWMS model the rhizosphere hydraulic properties differ from those of the bulk soil, and non-equilibrium dynamics between the rhizosphere water content and pressure head is also considered. We simulated a wetting scenario. The soil was initially dry and it was wetted from the top at a constant flow rate. The model predicts that, after infiltration the water content in the rhizosphere remained lower than in the bulk soil (non-equilibrium), but over time water infiltrated into the rhizosphere and eventually the water content in the rhizosphere became higher than in the bulk soil. These results are in qualitative agreement with the available experimental data on water dynamics in the rhizosphere. Additionally, the results show that rhizosphere processes

  1. Experimental study of water flow in nuclear fuel elements

    International Nuclear Information System (INIS)

    Rodrigues, Lorena Escriche; Rezende, Hugo Cesar; Mattos, Joao Roberto Loureiro de; Barros Filho, Jose Afonso; Santos, Andre Augusto Campagnole dos

    2013-01-01

    This work aims to develop an experimental methodology for investigating the water flow through rod bundles after spacer grids of nuclear fuel elements of PWR type reactors. Speed profiles, with the device LDV (Laser Doppler Velocimetry), and the pressure drop between two sockets located before and after the spacer grid, using pressure transducers were measured

  2. Water Flow Simulation using Smoothed Particle Hydrodynamics (SPH)

    Science.gov (United States)

    Vu, Bruce; Berg, Jared; Harris, Michael F.

    2014-01-01

    Simulation of water flow from the rainbird nozzles has been accomplished using the Smoothed Particle Hydrodynamics (SPH). The advantage of using SPH is that no meshing is required, thus the grid quality is no longer an issue and accuracy can be improved.

  3. Control algorithm for multiscale flow simulations of water

    DEFF Research Database (Denmark)

    Kotsalis, E. M.; Walther, Jens Honore; Kaxiras, E.

    2009-01-01

    We present a multiscale algorithm to couple atomistic water models with continuum incompressible flow simulations via a Schwarz domain decomposition approach. The coupling introduces an inhomogeneity in the description of the atomistic domain and prevents the use of periodic boundary conditions...

  4. Modelling flow dynamics in water distribution networks using ...

    African Journals Online (AJOL)

    DR OKE

    was used for modelling the flow and simulate water demand using a Matlab .... This process requires that the neural network compute the error derivative of the .... Furthermore, Matlab was used as a simulation tool; and the first step was ...

  5. Environmental flows and water quality objectives for the River Murray.

    Science.gov (United States)

    Gippel, C; Jacobs, T; McLeod, T

    2002-01-01

    Over the past decade, there intense consideration of managing flows in the River Murray to provide environmental benefits. In 1990 the Murray-Darling Basin Ministerial Council adopted a water quality policy: To maintain and, where necessary, improve existing water quality in the rivers of the Murray-Darling Basin for all beneficial uses - agricultural, environmental, urban, industrial and recreational, and in 1994 a flow policy: To maintain and where necessary improve existing flow regimes in the waterways of the Murray-Darling Basin to protect and enhance the riverine environment. The Audit of Water Use followed in 1995, culminating in the decision of the Ministerial Council to implement an interim cap on new diversions for consumptive use (the "Cap") in a bid to halt declining river health. In March 1999 the Environmental Flows and Water Quality Objectives for the River Murray Project (the Project) was set up, primarily to establish be developed that aims to achieve a sustainable river environment and water quality, in accordance with community needs, and including an adaptive approach to management and operation of the River. It will lead to objectives for water quality and environmental flows that are feasible, appropriate, have the support of the scientific, management and stakeholder communities, and carry acceptable levels of risk. This paper describes four key aspects of the process being undertaken to determine the objectives, and design the flow options that will meet those objectives: establishment of an appropriate technical, advisory and administrative framework; establishing clear evidence for regulation impacts; undergoing assessment of environmental flow needs; and filling knowledge gaps. A review of the impacts of flow regulation on the health of the River Murray revealed evidence for decline, but the case for flow regulation as the main cause is circumstantial or uncertain. This is to be expected, because the decline of the River Murray results

  6. Oil-water flows in wells with powerful fracture reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, N.P.

    1979-01-01

    The character of two phase liquid flows from powerful layer fractures to bottom holes in Starogrodnen and Malgobek-Voznesenskiy fields in the Chechen-Ingush ASSR found in the late stage of operation. The studies were done with the electrothermometer TEG-36, the manometer MGN-2, the remote control thermal flow meter T-4, the remote control moisture meter VBST-1, the density meter GGP-1M, whose accuracy class is 1.0 and whose working limits are: temperature, up to 150/sup 0/C and pressure, up to 1000 kGs/cm/sup 2/. The breakdown of the linear filtration law and the gravitational division of the water-oil mixture phase occurred during fieldwork. The oil and water, etc., flow intervals were defined. The data from the moisture meter and the gamma density meter coincided.

  7. Undesirable Effects of Media on Children: Why Limitation is Necessary?

    Science.gov (United States)

    Karaagac, Aysu Turkmen

    2015-06-01

    Pervasive media environment is a social problem shared by most of the countries around the world. Several studies have been performed to highlight the undesired effects of media on children. Some of these studies have focused on the time spent by children watching television, playing with computers or using mobile media devices while some others have tried to explain the associations between the obesity, postural abnormalities or psychological problems of children, and their media use. This article discusses the recent approaches to curb influence of media on children, and the importance of family media literacy education programs with particular relevance to developing countries.

  8. Characterization of horizontal air–water two-phase flow

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Ran; Kim, Seungjin, E-mail: skim@psu.edu

    2017-02-15

    Highlights: • A visualization study is performed to develop flow regime map in horizontal flow. • Database in horizontal bubbly flow is extended using a local conductivity probe. • Frictional pressure drop analysis is performed in horizontal bubbly flow. • Drift flux analysis is performed in horizontal bubbly flow. - Abstract: This paper presents experimental studies performed to characterize horizontal air–water two-phase flow in a round pipe with an inner diameter of 3.81 cm. A detailed flow visualization study is performed using a high-speed video camera in a wide range of two-phase flow conditions to verify previous flow regime maps. Two-phase flows are classified into bubbly, plug, slug, stratified, stratified-wavy, and annular flow regimes. While the transition boundaries identified in the present study compare well with the existing ones (Mandhane et al., 1974) in general, some discrepancies are observed for bubbly-to-plug/slug, and plug-to-slug transition boundaries. Based on the new transition boundaries, three additional test conditions are determined in horizontal bubbly flow to extend the database by Talley et al. (2015a). Various local two-phase flow parameters including void fraction, interfacial area concentration, bubble velocity, and bubble Sauter mean diameter are obtained. The effects of increasing gas flow rate on void fraction, bubble Sauter mean diameter, and bubble velocity are discussed. Bubbles begin to coalesce near the gas–liquid layer instead of in the highly packed region when gas flow rate increases. Using all the current experimental data, two-phase frictional pressure loss analysis is performed using the Lockhart–Martinelli method. It is found that the coefficient C = 24 yields the best agreement with the data with the minimum average difference. Moreover, drift flux analysis is performed to predict void-weighted area-averaged bubble velocity and area-averaged void fraction. Based on the current database, functional

  9. Measurement of flowing water salinity within or behind wellbore casing

    International Nuclear Information System (INIS)

    Arnold, D.M.

    1981-01-01

    Water flowing within or behind a wellbore casing is irradiated with 14 MeV neutrons from a source in a downhole sonde. Gamma radiation from the isotope nitrogen-16 induced from the O 16 (n,p)N 16 reaction and the products of either the Na 23 (n,α)F 20 or the Cl 37 (n,α)P 34 reactions is measured in intensity and energy with detectors in the sonde. From the gamma radiation measurements, the relative presence of oxygen to at least one of sodium or chlorine in the water is measured, and from the measurement the salinity of the water is to be determined. (author)

  10. A Guide for Using the Transient Ground-Water Flow Model of the Death Valley Regional Ground-Water Flow System, Nevada and California

    Energy Technology Data Exchange (ETDEWEB)

    Joan B. Blainey; Claudia C. Faunt, and Mary C. Hill

    2006-05-16

    This report is a guide for executing numerical simulations with the transient ground-water flow model of the Death Valley regional ground-water flow system, Nevada and California using the U.S. Geological Survey modular finite-difference ground-water flow model, MODFLOW-2000. Model inputs, including observations of hydraulic head, discharge, and boundary flows, are summarized. Modification of the DVRFS transient ground-water model is discussed for two common uses of the Death Valley regional ground-water flow system model: predictive pumping scenarios that extend beyond the end of the model simulation period (1998), and model simulations with only steady-state conditions.

  11. Adjustable liquid aperture to eliminate undesirable light in holographic projection.

    Science.gov (United States)

    Wang, Di; Liu, Chao; Li, Lei; Zhou, Xin; Wang, Qiong-Hua

    2016-02-08

    In this paper, we propose an adjustable liquid aperture to eliminate the undesirable light in a holographic projection. The aperture is based on hydrodynamic actuation. A chamber is formed with a cylindrical tube. A black droplet is filled in the sidewall of the cylinder tube and the outside space is the transparent oil which is immiscible with the black droplet. An ultrathin glass sheet is attached on the bottom substrate of the device and a black shading film is secured to the central area of the glass sheet. By changing the volume of the black droplet, the black droplet will move to the middle or sidewall due to hydrodynamic actuation, so the device can be used as an adjustable aperture. A divergent spherical wave and a solid lens are used to separate the focus planes of the reconstructed image and diffraction beams induced by the liquid crystal on silicon in the holographic projection. Then the aperture is used to eliminate the diffraction beams by adjusting the size of the liquid aperture and the holographic projection does not have undesirable light.

  12. Undesirable substances in vegetable oils: anything to declare?

    Directory of Open Access Journals (Sweden)

    Lacoste Florence

    2014-01-01

    Full Text Available The presence of undesirable compounds in vegetable and animal oils and fats may have many different origins. Although the potential toxicity of most of these undesirable compounds is real, poisoning risks are rather limited due to the efficient elimination during oil-refining steps, careful conditioning, choice of efficient packaging and industrial quality control management. However the research of contaminants is part of multiple controls conducted by fat and oil industry to verify the conformity of products placed on the market in relation to regulations such as the European commission regulation EC No. 1881/2006 setting maximum levels for some contaminants in food as lead, some mycotoxins, dioxins, polychlorobiphenyls, benzo[a]pyrene. In the absence of regulation, the detection of contaminants must be addressed in partnership with authorities according to the toxicity of molecules. The controls are not confined to environmental contaminants. They also include compounds that can be formed during the production process of vegetable oils such as esters of 3-monochloropropanediol. This article focuses more particularly on heavy metals, polycyclic aromatic hydrocarbons, mineral oils, phthalates and 3-MCPD or glycidyl esters. Aspects such as methods for analysis, limits fixed by EC regulation and occurrence in vegetable oils are discussed.

  13. 75 FR 45579 - Water Quality Standards for the State of Florida's Lakes and Flowing Waters; Supplemental Notice...

    Science.gov (United States)

    2010-08-03

    ... Water Quality Standards for the State of Florida's Lakes and Flowing Waters; Supplemental Notice of Data...), proposing numeric nutrient water quality criteria to protect aquatic life in lakes and flowing waters within... will consider the comments received before finalizing the proposed rule, ``Water Quality Standards for...

  14. Radionuclide transfer onto ground surface in surface water flow, 1

    International Nuclear Information System (INIS)

    Mukai, Masayuki; Takebe, Shinichi; Komiya, Tomokazu; Kamiyama, Hideo

    1991-07-01

    Radionuclides migration in ground surface water flow is considered to be one of the important path way in the scenario for environmental migration of radionuclides leaked from low level radioactive waste repository. Simulating the slightly sloped surface on which contaminated solution is flowing downward, testing for radionuclide migration on ground surface had been started. As it's first step, an experiment was carried out under the condition of restricted infiltration in order to elucidate the adsorption behavior of radionuclides onto the loamy soil surface in related with hydraulic conditions. Radionuclides concentration change in effluent solution with time and a concentration distribution of radionuclides adsorbed on the ground surface were obtained from several experimental conditions combining the rate and the duration time of the water flow. The radionuclides concentration in the effluent solution was nearly constant during each experimental period, and was reduced under the condition of lower flow rate. The surface distribution of radionuclides concentration showed two distinctive regions. The one was near the inlet vessel where the concentration was promptly reducing, and the other was following the former where the concentration was nearly constant. The characteristic surface distribution of radionuclides concentration can be explained by a two dimensional diffusion model with a first order adsorption reaction, based on the advection of flow rate distribution in perpendicular direction. (author)

  15. Horizontal Air-Water Flow Analysis with Wire Mesh Sensor

    International Nuclear Information System (INIS)

    De Salve, M; Monni, G; Panella, B

    2012-01-01

    A Wire Mesh Sensor, based on the measurement of the local instantaneous conductivity of the two-phase mixture, has been used to characterize the fluid dynamics of the gas–liquid interface in a horizontal pipe flow. Experiments with a pipe of a nominal diameter of 19.5 mm and total length of 6 m, have been performed with air/water mixtures, at ambient conditions. The flow quality ranges from 0.00016 to 0.22 and the superficial velocities range from 0.1 to 10.5 m/s for air and from 0.02 to 1.7 m/s for water; the flow pattern is stratified, slug/plug and annular. A sensor (WMS200) with an inner diameter of 19.5 mm and a measuring matrix of 16×16 points equally distributed over the cross-section has been chosen for the measurements. From the analysis of the Wire Mesh Sensor digital signals the average and the local void fraction are evaluated and the flow patterns are identified with reference to space, time and flow rate boundary conditions.

  16. What maintains the waters flowing in our rivers?

    Science.gov (United States)

    Vasconcelos, Vitor Vieira

    2017-07-01

    This article discusses how new contributions from hydrogeological science in the 20th and 21st centuries have allowed for a better understanding of the processes that affect the maintenance of river flows. Moreover, the way in which this knowledge has been conveyed beyond academia and has been gradually incorporated into public policy for natural resource management is also discussed. This article explains the development of several approaches used to understand the relationships among the management of aquifers, vegetation and river flows, including water balance, aquifer recharge, the piston effect, seasonal effects, and safe and sustainable yields. Additionally, the current challenges regarding the modeling of hydrological processes that integrate groundwater and surface waters are discussed. Examples of studies applied in Brazil that demonstrate these processes and stimulate thought regarding water management strategies are presented. In light of the case studies, it is possible to propose different strategies, each adapted for specific hydrogeological context to maximize aquifer recharge or base flow maintenance. Based on these strategies, the role of infiltration ponds and other artificial recharge techniques is re-evaluated in the context of the mitigation of environmental impacts on the maintenance of river flows. Proposals for the improvement of public policies regarding the payment of related environmental services to stimulate investment in aquifer recharge and the maintenance of base flow, for which the goal is to attain win-win-win situations for the environment, farmers and water users, while preventing land speculation, are discussed. Lastly, a conceptual model for the dissemination of hydrogeological knowledge in public policies is provided, and its challenges and possibilities are discussed.

  17. A Comparison of Simplified Two-dimensional Flow Models Exemplified by Water Flow in a Cavern

    Science.gov (United States)

    Prybytak, Dzmitry; Zima, Piotr

    2017-12-01

    The paper shows the results of a comparison of simplified models describing a two-dimensional water flow in the example of a water flow through a straight channel sector with a cavern. The following models were tested: the two-dimensional potential flow model, the Stokes model and the Navier-Stokes model. In order to solve the first two, the boundary element method was employed, whereas to solve the Navier-Stokes equations, the open-source code library OpenFOAM was applied. The results of numerical solutions were compared with the results of measurements carried out on a test stand in a hydraulic laboratory. The measurements were taken with an ADV probe (Acoustic Doppler Velocimeter). Finally, differences between the results obtained from the mathematical models and the results of laboratory measurements were analysed.

  18. Local properties of countercurrent stratified steam-water flow

    International Nuclear Information System (INIS)

    Kim, H.J.

    1985-10-01

    A study of steam condensation in countercurrent stratified flow of steam and subcooled water has been carried out in a rectangular channel/flat plate geometry over a wide range of inclination angles (4 0 -87 0 ) at several aspect ratios. Variables were inlet water and steam flow rates, and inlet water temperature. Local condensation rates and pressure gradients were measured, and local condensation heat transfer coefficients and interfacial shear stress were calculated. Contact probe traverses of the surface waves were made, which allowed a statistical analysis of the wave properties. The local condensation Nusselt number was correlated in terms of local water and steam Reynolds or Froude numbers, as well as the liquid Prandtl number. A turbulence-centered model developed by Theofanous, et al. principally for gas absorption in several geometries, was modified. A correlation for the interfacial shear stress and the pressure gradient agreed with measured values. Mean water layer thicknesses were calculated. Interfacial wave parameters, such as the mean water layer thickness, liquid fraction probability distribution, wave amplitude and wave frequency, are analyzed

  19. The physics of confined flow and its application to water leaks, water permeation and water nanoflows: a review

    International Nuclear Information System (INIS)

    Lei, Wenwen; Rigozzi, Michelle K; McKenzie, David R

    2016-01-01

    This review assesses the current state of understanding of the calculation of the rate of flow of gases, vapours and liquids confined in channels, in porous media and in permeable materials with an emphasis on the flow of water and its vapour. One motivation is to investigate the relation between the permeation rate of moisture and that of a noncondensable test gas such as helium, another is to assist in unifying theory and experiment across disparate fields. Available theories of single component ideal gas flows in channels of defined geometry (cylindrical, rectangular and elliptical) are described and their predictions compared with measurement over a wide range of conditions defined by the Knudsen number. Theory for two phase flows is assembled in order to understand the behaviour of four standard water leak configurations: vapour, slug, Washburn and liquid flow, distinguished by the number and location of phase boundaries (menisci). Air may or may not be present as a background gas. Slip length is an important parameter that greatly affects leak rates. Measurements of water vapour flows confirm that water vapour shows ideal gas behaviour. Results on carbon nanotubes show that smooth walls may lead to anomalously high slip lengths arising from the properties of ‘confined’ water. In porous media, behaviour can be matched to the four standard leaks. Traditional membrane permeation models consider that the permeant dissolves, diffuses and evaporates at the outlet side, ideas we align with those from channel flow. Recent results on graphite oxide membranes show examples where helium which does not permeate while at the same time moisture is almost unimpeded, again a result of confined water. We conclude that while there is no a priori relation between a noncondensable gas flow and a moisture flow, measurements using helium will give results within two orders of magnitude of the moisture flow rate, except in the case where there is anomalous slip or confined

  20. The physics of confined flow and its application to water leaks, water permeation and water nanoflows: a review.

    Science.gov (United States)

    Lei, Wenwen; Rigozzi, Michelle K; McKenzie, David R

    2016-02-01

    This review assesses the current state of understanding of the calculation of the rate of flow of gases, vapours and liquids confined in channels, in porous media and in permeable materials with an emphasis on the flow of water and its vapour. One motivation is to investigate the relation between the permeation rate of moisture and that of a noncondensable test gas such as helium, another is to assist in unifying theory and experiment across disparate fields. Available theories of single component ideal gas flows in channels of defined geometry (cylindrical, rectangular and elliptical) are described and their predictions compared with measurement over a wide range of conditions defined by the Knudsen number. Theory for two phase flows is assembled in order to understand the behaviour of four standard water leak configurations: vapour, slug, Washburn and liquid flow, distinguished by the number and location of phase boundaries (menisci). Air may or may not be present as a background gas. Slip length is an important parameter that greatly affects leak rates. Measurements of water vapour flows confirm that water vapour shows ideal gas behaviour. Results on carbon nanotubes show that smooth walls may lead to anomalously high slip lengths arising from the properties of 'confined' water. In porous media, behaviour can be matched to the four standard leaks. Traditional membrane permeation models consider that the permeant dissolves, diffuses and evaporates at the outlet side, ideas we align with those from channel flow. Recent results on graphite oxide membranes show examples where helium which does not permeate while at the same time moisture is almost unimpeded, again a result of confined water. We conclude that while there is no a priori relation between a noncondensable gas flow and a moisture flow, measurements using helium will give results within two orders of magnitude of the moisture flow rate, except in the case where there is anomalous slip or confined water

  1. Computational fluid dynamics simulations of light water reactor flows

    International Nuclear Information System (INIS)

    Tzanos, C.P.; Weber, D.P.

    1999-01-01

    Advances in computational fluid dynamics (CFD), turbulence simulation, and parallel computing have made feasible the development of three-dimensional (3-D) single-phase and two-phase flow CFD codes that can simulate fluid flow and heat transfer in realistic reactor geometries with significantly reduced reliance, especially in single phase, on empirical correlations. The objective of this work was to assess the predictive power and computational efficiency of a CFD code in the analysis of a challenging single-phase light water reactor problem, as well as to identify areas where further improvements are needed

  2. Hydroelectric power plant with variable flow on drinking water adduction

    Science.gov (United States)

    Deaconu, S. I.; Babău, R.; Popa, G. N.; Gherman, P. L.

    2018-01-01

    The water feeding system of the urban and rural localities is mainly collected with feed pipes which can have different lengths and different levels. Before using, water must be treated. Since the treatment take place in the tanks, the pressure in the inlet of the station must be diminished. Many times the pressure must be reduced with 5-15 Barr and this is possible using valves, cavils, and so on. The flow capacity of the water consumption is highly fluctuating during one day, depending on the season, etc. This paper presents a method to use the hydroelectric potential of the feed pipes using a hydraulic turbine instead of the classical methods for decreasing the pressure. To avoid the dissipation of water and a good behavior of the power parameters it is used an asynchronous generator (AG) which is coupled at the electrical distribution network through a static frequency converter (SFC). The turbine has a simple structure without the classical devices (used to regulate the turbine blades). The speed of rotation is variable, depending on the necessary flow capacity in the outlet of the treatment station. The most important element of the automation is the static frequency converter (SFC) which allows speeds between 0 and 1.5 of the rated speed of rotation and the flow capacity varies accordingly with it.

  3. Investigation on flow stability of supercritical water cooled systems

    International Nuclear Information System (INIS)

    Cheng, X.; Kuang, B.

    2006-01-01

    Research activities are ongoing worldwide to develop nuclear power plants with supercritical water cooled reactor (SCWR) with the purpose to achieve a high thermal efficiency and to improve their economical competitiveness. However, the strong variation of the thermal-physical properties of water in the vicinity of the pseudo-critical line results in challenging tasks in various fields, e.g. thermal-hydraulic design of a SCWR. One of the challenging tasks is to understand and to predict the dynamic behavior of supercritical water cooled systems. Although many thermal-hydraulic research activities were carried out worldwide in the past as well as in the near present, studies on dynamic behavior and flow stability of SC water cooled systems are scare. Due to the strong density variation, flow stability is expected to be one of the key items which need to be taken into account in the design of a SCWR. In the present work, the dynamic behavior and flow stability of SC water cooled systems are investigated using both numerical and theoretical approaches. For this purpose a new computer code SASC was developed, which can be applied to analysis the dynamic behavior of systems cooled by supercritical fluids. In addition, based on the assumptions of a simplified system, a theoretical model was derived for the prediction of the onset of flow instability. A comparison was made between the results obtained using the theoretical model and those from the SASC code. A good agreement was achieved. This gives the first evidence of the reliability of both the SASC code and the theoretical model

  4. Turbulent flow over an interactive alternating land-water surface

    Science.gov (United States)

    Van Heerwaarden, C.; Mellado, J. P.

    2014-12-01

    The alternating land-water surface is a challenging surface to represent accurately in weather and climate models, but it is of great importance for the surface energy balance in polar regions. The complexity of this surface lies in the fact that secondary circulations, which form at the boundary of water and land, interact strongly with the surface energy balance. Due to its large heat capacity, the water temperature adapts slowly to the flow, thus the properties of the atmosphere determine the uptake of energy from the water. In order to study this complex system in a simpler way, retaining only the most essential physics, we have simplified the full surface energy balance including radiation. We have derived a boundary condition that mimics the full balance and can be formulated as a so-called Robin boundary condition: a linear combination of Dirichlet (fixed temperature) and Neumann (fixed temperature gradient) ones. By spatially varying the coefficients, we are able to express land and water using this boundary condition. We have done a series of direct numerical simulations in which we generate artificial land-water patterns from noise created from a Gaussian spectrum centered around a dominant wave number. This method creates realistic random patterns, but we are still in control of the length scales. We show that the system can manifest itself in three regimes: micro-, meso- and macro-scale. In the micro-scale, we find perfect mixing of the near-surface atmosphere that results in identical air properties over water and land. In the meso-scale, secondary circulations alter the heat exchange considerably by advecting air between land and water. In addition, they bring the surface temperature of the land closer to that of the air, thereby modulating the energy loss due to outgoing longwave radiation. In the macro-scale regime, the flow over land and water become independent of each other and only the large scale forcings determine the energy balance.

  5. Uncovering regional disparity of China's water footprint and inter-provincial virtual water flows.

    Science.gov (United States)

    Dong, Huijuan; Geng, Yong; Fujita, Tsuyoshi; Fujii, Minoru; Hao, Dong; Yu, Xiaoman

    2014-12-01

    With rapid economic development in China, water crisis is becoming serious and may impede future sustainable development. The uneven distribution of water resources further aggravates such a problem. Under such a circumstance, the concepts of water footprint and virtual water have been proposed in order to respond water scarcity problems. This paper focuses on studying provincial disparity of China's water footprints and inter-provincial virtual water trade flows by adopting inter-regional input-output (IRIO) method. The results show that fast developing areas with larger economic scales such as Guangdong, Jiangsu, Shandong, Zhejiang, Shanghai and Xinjiang had the largest water footprints. The most developed and water scarce areas such as Shanghai, Beijing, Tianjin and Shandong intended to import virtual water, a rational choice for mitigating their water crisis. Xinjiang, Jiangsu, Heilongjiang, Inner Mongolia, Guangxi and Hunan, had the largest per GDP water intensities and were the main water import regions. Another key finding is that agriculture water footprint was the main part in water footprint composition and water export trade. On the basis of these findings, policy implications on agriculture geographical dispersion, consumption behavior changes, trade structure adjustment and water use efficiency improvement are further discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Removing the impact of water abstractions on flow duration curves

    Science.gov (United States)

    Masoero, Alessandro; Ganora, Daniele; Galeati, Giorgio; Laio, Francesco; Claps, Pierluigi

    2015-04-01

    Changes and interactions between human system and water cycle are getting increased attention in the scientific community. Commonly discharge data needed for water resources studies were collected close to urban or industrial settlements, thus in environments where the interest for surveying was not merely scientific, but also for socio-economical purposes. Working in non-natural environments we must take into account human impacts, like the one due to water intakes for irrigation or hydropower generation, while assessing the actual water availability and variability in a river. This can became an issue in alpine areas, where hydropower exploitation is heavy and it is common to have water abstraction before a gauge station. To have a gauge station downstream a water intake can be useful to survey the environmental flow release and to record the maximum flood values, which should not be affected by the water abstraction. Nevertheless with this configuration we are unable to define properly the water volumes available in the river, information crucial to assess low flows and investigate drought risk. This situation leads to a substantial difference between observed data (affected by the human impact) and natural data (as would have been without abstraction). A main issue is how to correct these impacts and restore the natural streamflow values. The most obvious and reliable solution would be to ask for abstraction data to water users, but these data are hard to collect. Usually they are not available, because not public or not even collected by the water exploiters. A solution could be to develop a rainfall-run-off model of the basin upstream the gauge station, but this approach needs a great number of data and parameters Working in a regional framework and not on single case studies, our goal is to provide a consistent estimate of the non-impacted statistics of the river (i.e. mean value, L-moments of variation and skewness). We proposed a parsimonious method, based

  7. Flow structure from a horizontal cylinder coincident with a free surface in shallow water flow

    Directory of Open Access Journals (Sweden)

    Kahraman Ali

    2012-01-01

    Full Text Available Vortex formation from a horizontal cylinder coincident with a free surface of a shallow water flow having a depth of 25.4 [mm] was experimentally investigated using the PIV technique. Instantaneous and time-averaged flow patterns in the wake region of the cylinder were examined for three different cylinder diameter values under the fully developed turbulent boundary layer condition. Reynolds numbers were in the range of 1124£ Re£ 3374 and Froude numbers were in the range of 0.41 £ Fr £ 0.71 based on the cylinder diameter. It was found that a jet-like flow giving rise to increasing the flow entrainment between the core and wake regions depending on the cylinder diameter was formed between the lower surface of the cylinder and bottom surface of the channel. Vorticity intensity, Reynolds stress correlations and the primary recirculating bubble lengths were grown to higher values with increasing the cylinder diameter. On the other hand, in the case of the lowest level of the jet-like flow emanating from the beneath of the smallest cylinder, the variation of flow characteristics were attenuated significantly in a shorter distance. The variation of the reattachment location of the separated flow to the free-surface is a strong function of the cylinder diameter and the Froude number.

  8. Preferential flow in water-repellent sandy soils : model development and lysimeter experiments

    NARCIS (Netherlands)

    Rooij, de G.H.

    1996-01-01


    When water enters a water-repellent topsoil, preferential flow paths develop and the flow bypasses a large part of the unsaturated zone. Therefore, preferential flow caused by water- repellency is expected to accelerate solute leaching to the groundwater. In soils with water-repellent

  9. Nonlinear analysis of gas-water/oil-water two-phase flow in complex networks

    CERN Document Server

    Gao, Zhong-Ke; Wang, Wen-Xu

    2014-01-01

    Understanding the dynamics of multi-phase flows has been a challenge in the fields of nonlinear dynamics and fluid mechanics. This chapter reviews our work on two-phase flow dynamics in combination with complex network theory. We systematically carried out gas-water/oil-water two-phase flow experiments for measuring the time series of flow signals which is studied in terms of the mapping from time series to complex networks. Three network mapping methods were proposed for the analysis and identification of flow patterns, i.e. Flow Pattern Complex Network (FPCN), Fluid Dynamic Complex Network (FDCN) and Fluid Structure Complex Network (FSCN). Through detecting the community structure of FPCN based on K-means clustering, distinct flow patterns can be successfully distinguished and identified. A number of FDCN’s under different flow conditions were constructed in order to reveal the dynamical characteristics of two-phase flows. The FDCNs exhibit universal power-law degree distributions. The power-law exponent ...

  10. Tribocorrosion in pressurized high temperature water: a mass flow model based on the third body approach

    Energy Technology Data Exchange (ETDEWEB)

    Guadalupe Maldonado, S.

    2014-07-01

    Pressurized water reactors (PWR) used for power generation are operated at elevated temperatures (280-300 °C) and under higher pressure (120-150 bar). In addition to these harsh environmental conditions some components of the PWR assemblies are subject to mechanical loading (sliding, vibration and impacts) leading to undesirable and hardly controllable material degradation phenomena. In such situations wear is determined by the complex interplay (tribocorrosion) between mechanical, material and physical-chemical phenomena. Tribocorrosion in PWR conditions is at present little understood and models need to be developed in order to predict component lifetime over several decades. The goal of this project, carried out in collaboration with the French company AREVA NP, is to develop a predictive model based on the mechanistic understanding of tribocorrosion of specific PWR components (stainless steel control assemblies, stellite grippers). The approach taken here is to describe degradation in terms of electro-chemical and mechanical material flows (third body concept of tribology) from the metal into the friction film (i.e. the oxidized film forming during rubbing on the metal surface) and from the friction film into the environment instead of simple mass loss considerations. The project involves the establishment of mechanistic models for describing the single flows based on ad-hoc tribocorrosion measurements operating at low temperature. The overall behaviour at high temperature and pressure in investigated using a dedicated tribometer (Aurore) including electrochemical control of the contact during rubbing. Physical laws describing the individual flows according to defined mechanisms and as a function of defined physical parameters were identified based on the obtained experimental results and from literature data. The physical laws were converted into mass flow rates and solved as differential equation system by considering the mass balance in compartments

  11. Relating water and air flow characteristics in coarse granular materials

    DEFF Research Database (Denmark)

    Andreasen, Rune Røjgaard; Canga, Eriona; Poulsen, Tjalfe Gorm

    2013-01-01

    Water pressure drop as a function of velocity controls w 1 ater cleaning biofilter operation 2 cost. At present this relationship in biofilter materials must be determined experimentally as no 3 universal link between pressure drop, velocity and filter material properties have been established. 4...... Pressure drop - velocity in porous media is much simpler and faster to measure for air than for water. 5 For soils and similar materials, observations show a strong connection between pressure drop – 6 velocity relations for air and water, indicating that water pressure drop – velocity may be estimated 7...... from air flow data. The objective of this study was, therefore, to investigate if this approach is valid 8 also for coarse granular biofilter media which usually consists of much larger particles than soils. In 9 this paper the connection between the pressure drop – velocity relationships for air...

  12. [Undesired treatment effects in behavior group therapy: Frequency and spectrum].

    Science.gov (United States)

    Linden, M; Walter, M; Fritz, K; Muschalla, B

    2015-11-01

    Psychotherapy not only has positive but also negative effects, which is especially true for group psychotherapy due to psychodynamic and interactional processes. Using the UE-G questionnaire 71 patients who participated in cognitive behavioral group psychotherapy reported on negative experiences in the context of the group therapy. The answers were then validated in a qualitative interview. Of the patients 98.6% reported about at least one negative experience and 43.7% about severe or extremely severe negative experiences. Most prominent was the induction of hopelessness and demoralization by what patients saw and heard from other patients in the group. Burdensome and therefore undesired treatment effects are regularly seen in group psychotherapy, because of treatment or patient related factors. In any case they must be taken into account during treatment, in the training of group psychotherapists and in quality control.

  13. Study on performance and flow field of an undershot cross-flow water turbine comprising different number of blades

    Science.gov (United States)

    Nishi, Yasuyuki; Hatano, Kentaro; Inagaki, Terumi

    2017-10-01

    Recently, small hydroelectric generators have gained attention as a further development in water turbine technology for ultra low head drops in open channels. The authors have evaluated the application of cross-flow water turbines in open channels as an undershot type after removing the casings and guide vanes to substantially simplify these water turbines. However, because undershot cross-flow water turbines are designed on the basis of cross-flow water turbine runners used in typical pipelines, it remains unclear whether the number of blades has an effect on the performance or flow fields. Thus, in this research, experiments and numerical analyses are employed to study the performance and flow fields of undershot cross-flow water turbines with varying number of blades. The findings show that the turbine output and torque are lower, the fluctuation is significantly higher, and the turbine efficiency is higher for runners with 8 blades as opposed to those with 24 blades.

  14. Analysis of a solar collector field water flow network

    Science.gov (United States)

    Rohde, J. E.; Knoll, R. H.

    1976-01-01

    A number of methods are presented for minimizing the water flow variation in the solar collector field for the Solar Building Test Facility at the Langley Research Center. The solar collector field investigated consisted of collector panels connected in parallel between inlet and exit collector manifolds to form 12 rows. The rows were in turn connected in parallel between the main inlet and exit field manifolds to complete the field. The various solutions considered included various size manifolds, manifold area change, different locations for the inlets and exits to the manifolds, and orifices or flow control valves. Calculations showed that flow variations of less than 5 percent were obtainable both inside a row between solar collector panels and between various rows.

  15. Diphasic flow downstream of circulation-water condenser during priming

    International Nuclear Information System (INIS)

    Ibler, B.; Sabaton, M.; Canavelis, R.

    1982-01-01

    The experimental study presented here describes the experiments for visualizing diphasic flow carried out on a 1/10 model of a circulation-water condenser for a 1,300-MW nuclear power unit. The essential object of the experiments was to validate the layout for the tubing proposed by the Design Office, from the point of view of its incidence on the stability of the flows and the mechanical solidity of the structures during the relatively anarchical phase of automatic priming of the condenser. The observations made have rendered it possible firstly to analyse the pattern of flows in greater detail and secondly to conclude that a simplified and cheaper layout of pipes is acceptable without great risk [fr

  16. A seepage meter designed for use in flowing water

    Science.gov (United States)

    Rosenberry, D.O.

    2008-01-01

    Seepage meters provide one of the most direct means to measure exchange of water across the sediment-water interface, but they generally have been unsuitable for use in fluvial settings. Although the seepage bag can be placed inside a rigid container to minimize velocity head concerns, the seepage cylinder installed in the sediment bed projects into and disrupts the flow field, altering both the local-scale fluid exchange as well as measurement of that exchange. A low-profile seepage meter designed for use in moving water was tested in a seepage meter flux tank where both current velocity and seepage velocity could be controlled. The conical seepage cylinder protrudes only slightly above the sediment bed and is connected via tubing to a seepage bag or flowmeter positioned inside a rigid shelter that is located nearby where current velocity is much slower. Laboratory and field tests indicate that the net effect of the small protrusion of the seepage cylinder into the surface water flow field is inconsequentially small for surface water currents up to 65 cm s-1. Current velocity affects the variability of seepage measurements; seepage standard deviation increased from ???2 to ???6 cm d-1 as current velocity increased from 9 to 65 cm s-1. Substantial bias can result if the shelter is not placed to minimize hydraulic gradient between the bag and the seepage cylinder.

  17. Flow instability and turbulence - ONERA water tunnel visualizations

    Science.gov (United States)

    Werle, H.

    The experimental technique used for visualizing laminar-turbulent transition phenomena, developed in previous tests in ONERA's small TH1 water tunnel, has been successfully applied in the new TH2 tunnel. With its very extensive Reynold's number domain (10 to the 4th - 10 to the 6th), this tunnel has shown itself to be well adapted to the study of turbulence and of the flow instabilities related to its appearance.

  18. Biological control of schistosome transmission in flowing water habitats.

    Science.gov (United States)

    Jobin, W R; Laracuente, A

    1979-09-01

    Marisa cornuarietis was evaluated in Puerto Rico for control of schistosome transmission in flowing water. A population of Biomphalaria glabrata and their schistosome infections disappeared after introduction of 20,000 M. cornuarietis to an endemic stream, while in nearby untreated streams the B. glabrata population remained stable and the schistosome prevalence increased. This method cost U.S. $0.10 per capita for over a year of protection, 5%-10% of the cost of chemical control.

  19. Cosmetics Europe Guidelines on the Management of Undesirable Effects and Reporting of Serious Undesirable Effects from Cosmetics in the European Union

    Directory of Open Access Journals (Sweden)

    Gerald Renner

    2017-01-01

    Full Text Available The European Union (EU Cosmetics Regulation (EC No. 1223/2009 requires companies to collect and assess reports of adverse health effects from the cosmetic products (undesirable effects they market. Furthermore, undesirable effects that are considered as serious need to be reported to the national competent authorities. Cosmetics Europe, representing the European cosmetics industry, has developed these guidelines to promote a consistent practical approach for the management of undesirable effects and the notification of serious undesirable effects. Following these guidelines allows companies concerned to demonstrate due diligence and compliance with the legal requirements.

  20. Mechanisms of flow and water mass variability in Denmark Strait

    Science.gov (United States)

    Moritz, Martin; Jochumsen, Kerstin; Quadfasel, Detlef; Mashayekh Poul, Hossein; Käse, Rolf H.

    2017-04-01

    The dense water export through Denmark Strait contributes significantly to the lower limb of the Atlantic Meridional Overturning Circulation. Overflow water is transported southwestward not only in the deep channel of the Strait, but also within a thin bottom layer on the Greenland shelf. The flow on the shelf is mainly weak and barotropic, exhibiting many recirculations, but may eventually contribute to the overflow layer in the Irminger Basin by spilling events in the northern Irminger Basin. Especially the circulation around Dohrn Bank and the Kangerdlussuaq Trough contribute to the shelf-basin exchange. Moored observations show the overflow in Denmark Strait to be stable during the last 20 years (1996-2016). Nevertheless, flow variability was noticed on time scales of eddies and beyond, i.e. on weekly and interannual scales. Here, we use a combination of mooring data and shipboard hydrographic and current data to address the dominant modes of variability in the overflow, which are (i) eddies, (ii) barotropic pulsations of the plume, (iii) lateral shifts of the plume core position, and (iv) variations in vertical extension, i.e. varying overflow thickness. A principle component analysis is carried out and related to variations in sea surface height and wind stress, derived from satellite measurements. Furthermore, a test for topographic waves is performed. Shelf contributions to the overflow core in the Irminger Basin are identified from measurements of temperature and salinity, as well as velocity, which were obtained during recent cruises in the region. The flow and water mass pattern obtained from the observational data is compared to simulations in a high resolution regional model (ROMS), where tracer release experiments and float deployments were carried out. The modelling results allow a separation between different atmospheric forcing modes (NAO+ vs NAO- situations), which impact the water mass distribution and alter the dense water pathways on the

  1. Water flow simulation and analysis in HMA microstructure

    Directory of Open Access Journals (Sweden)

    Can Chen

    2014-10-01

    Full Text Available This paper introduces a new method for reconstructing virtual two-dimensional (2-D microstructure of hot mix asphalt (HMA. Based on the method, the gradation of coarse aggregates and the film thickness of the asphalt binder can be defined by the user. The HMA microstructure then serves as the input to the computational fluid dynamic (CFD software (ANSYS-FLUENT to investigate the water flow pattern through it. It is found that the realistic flow fields can be simulated in the 2-D micro-structure and the flow patterns in some typical air void structures can be identified. These flow patterns can be used to explain the mechanism that could result in moisture damage in HMA pavement. The one-dimensional numerical permeability values are also derived from the flow fields of the 2-D HMA microstructure and compared with the measured values obtained by the Karol-Warner permeameter. Because the interconnected air voids channels in actual HMA samples cannot be fully represented in a 2-D model, some poor agreements need to be improved.

  2. Effects of rainfall on water quality in six sequentially disposed fishponds with continuous water flow

    Directory of Open Access Journals (Sweden)

    LH. Sipaúba-Tavares

    Full Text Available An investigation was carried out during the rainy period in six semi-intensive production fish ponds in which water flowed from one pond to another without undergoing any treatment. Eight sampling sites were assigned at pond outlets during the rainy period (December-February. Lowest and highest physical and chemical parameters of water occurred in pond P1 (a site near the springs and in pond P4 (a critical site that received allochthonous material from the other ponds and also from frog culture ponds, respectively. Pond sequential layout caused concentration of nutrients, chlorophyll-a and conductivity. Seasonal rains increased the water flow in the ponds and, consequently, silted more particles and other dissolved material from one fish pond to another. Silting increased limnological variables from P3 to P6. Although results suggest that during the period under analysis, rainfall affected positively the ponds' water quality and since the analyzed systems have been aligned in a sequential layout with constant water flow from fish ponds and parallel tanks without any previous treatment, care has to be taken so that an increase in rain-induced water flow does not have a contrary effect in the fish ponds investigated.

  3. Integrating Flow, Form, and Function for Improved Environmental Water Management

    Science.gov (United States)

    Albin Lane, Belize Arela

    Rivers are complex, dynamic natural systems. The performance of river ecosystem functions, such as habitat availability and sediment transport, depends on the interplay of hydrologic dynamics (flow) and geomorphic settings (form). However, most river restoration studies evaluate the role of either flow or form without regard for their dynamic interactions. Despite substantial recent interest in quantifying environmental water requirements to support integrated water management efforts, the absence of quantitative, transferable relationships between river flow, form, and ecosystem functions remains a major limitation. This research proposes a novel, process-driven methodology for evaluating river flow-form-function linkages in support of basin-scale environmental water management. This methodology utilizes publically available geospatial and time-series data and targeted field data collection to improve basic understanding of river systems with limited data and resource requirements. First, a hydrologic classification system is developed to characterize natural hydrologic variability across a highly altered, physio-climatically diverse landscape. Next, a statistical analysis is used to characterize reach-scale geomorphic variability and to investigate the utility of topographic variability attributes (TVAs, subreach-scale undulations in channel width and depth), alongside traditional reach-averaged attributes, for distinguishing dominant geomorphic forms and processes across a hydroscape. Finally, the interacting roles of flow (hydrologic regime, water year type, and hydrologic impairment) and form (channel morphology) are quantitatively evaluated with respect to ecosystem functions related to hydrogeomorphic processes, aquatic habitat, and riparian habitat. Synthetic river corridor generation is used to evaluate and isolate the role of distinct geomorphic attributes without the need for intensive topographic surveying. This three-part methodology was successfully

  4. Flow analysis in a supercritical water oxidation reactor

    International Nuclear Information System (INIS)

    Oh, C.H.; Kochan, R.J.; Beller, J.M.

    1996-01-01

    Supercritical water oxidation (SCWO), also known as hydrothermal oxidation (HTO), involves the oxidation of hazardous waste at conditions of elevated temperature and pressure (e.g., 500 C--600 C and 234.4 bar) in the presence of approximately 90% of water and a 10% to 20% excess amount of oxidant over the stoichiometric requirement. Under these conditions, organic compounds are completely miscible with supercritical water, oxygen and nitrogen, and are rapidly oxidized to carbon dioxide and water. The essential part of the process is the reactor. Many reactor designs such as tubular, vertical vessel, and transpiring wall type have been proposed, patented, and tested at both bench and pilot scales. These designs and performances need to be scaled up to a waste throughput 10--100 times that currently being tested. Scaling of this magnitude will be done by creating a numerical thermal-hydraulic model of the smaller reactor for which test data is available, validating the model against the available data, and then using the validated model to investigate the larger reactor performance. This paper presents a flow analysis of the MODAR bench scale reactor (vertical vessel type). These results will help in the design of the reactor in an efficient manner because the flow mixing coupled with chemical kinetics eventually affects the process destruction efficiency

  5. Numerical study of saturation steam/water mixture flow and flashing initial sub-cooled water flow inside throttling devices

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    In this work, a Computational Fluid-Dynamics (CFD) approach to model this phenomenon inside throttling devices is proposed. To validate CFD results, different nozzle geometries are analyzed, comparing numerical results with experimental data. Two cases are studied: Case 1: saturation steam/water mixture flow inside 2D convergent-divergent nozzle (inlet, outlet and throat diameter of nozzle are 0.1213m, 0.0452m and 0.0191m respectively). In this benchmark, a range of total inle...

  6. Within plant resistance to water flow in tomato and sweet melons ...

    African Journals Online (AJOL)

    Efficient water resource management in relation to water use and crop yields is premised on the knowledge of plant resistance to water flow. However, such studies are limited and for most crops, the within plant resistance to water flow remains largely unknown. In this study, within plant resistance to water transport ...

  7. Investigations into the water flow and water conduction in spruce trees

    International Nuclear Information System (INIS)

    Strack, S.; Unger, H.

    1988-02-01

    The water-flow systems in the xylem of healthy and ailing spruce trees, based on the distribution patterns of tritiated water (HTO), were compared. In case of the ailing tree a severely altered water-flow system was observed. Whereas in the healthy tree the injected HTO spread in the apex in a distinctly differentiated manner following the spiral pattern of the ligneous fibers, no comparable spreading pattern was detected in the ailing tree. Also the labeled water molecules distributed twice as fast in the ailing as in the healthy tree. We conclude that the water conducting cross section of the diseased tree is reduced. Indeed, heartwood formation was about 60% in the ailing as compared to 5-20% in healthy trees. The methods of determining water content in the annual rings are described. The tissue water of needles from the healthy tree showed a distinct gradation of tritium concentrations according to age. This finding suggests that there is an age specific stomatal regulation in the healthy but not in the diseased needles. Water potential measurements at various times during the vegetation period provided evidence of a tighter water budget in diseased trees; however, a chronically enhanced water stress was not evident. The role of pathological heartwood formation during the disease is discussed. (orig.) With 27 figs., 38 refs [de

  8. Investigation of water flows inside of Ukrytie object

    International Nuclear Information System (INIS)

    Bogatov, S.A.; Korneev, A.A.; Krinitsyn, A.P.; Simanovskaya, I.Ya.; Strikhar', O.L.

    2000-01-01

    Superior limits of moisture admission in the most danger places of the B block and accessory systems of reactor part (RPAS) of the Ukrytie object by means of atmospheric precipitation (1950 m 3 /year), condensation processes in spring-summer period (1650 m 3 /year) and from technogenic sources (180 m 3 /year) are estimated. It is shown that moisture is removed from the Ukrytie object due to evaporation in autumn-winter (september-april) period (2100 m 3 /year) and as a result of not organized leaks. Using tracer method basic water flows inside the Ukrytie object and dynamic of leaking of block water from northern part of the 4-th block are determined. Experimental investigations show that as a result of not organized leaks from 001/3 room of RPAS of the 4-th block not less than 1000 m 3 /year of highly radioactive waters leak into drainage system of the 3-d block [ru

  9. Water flow in soil from organic dairy rotations

    DEFF Research Database (Denmark)

    Lamandé, Mathieu; Eriksen, Jørgen; Krogh, Paul Henning

    2017-01-01

    rye. Each plot was irrigated for an hour with 18·5 mm of water containing a conservative tracer, potassium bromide; 24 h after irrigation, macropores >1 mm were recorded visually on a horizontal plan of 0·7 m2 at five depths (10, 30, 40, 70 and 100 cm). The bromide (Br−) concentration in soil was also......Managed grasslands are characterized by rotations of leys and arable crops. The regime of water flow evolves during the leys because of earthworm and root activity, climate and agricultural practices (fertilizer, cutting and cattle trampling). The effects of duration of the leys, cattle trampling...... and fertilizer practice on the movement of water through sandy loam soil profiles were investigated in managed grassland of a dairy operation. Experiments using tracer chemicals were performed, with or without cattle slurry application, with cutting or grazing, in the 1st and the 3rd year of ley, and in winter...

  10. Water flow exchange characteristics in coarse granular filter media

    DEFF Research Database (Denmark)

    Andreasen, Rune Røjgaard; Pugliese, Lorenzo; Poulsen, Tjalfe

    2013-01-01

    Elution of inhibitory metabolites is a key parameter controlling the efficiency of air cleaning bio- and biotrickling filters. To the authors knowledge no studies have yet considered the relationship between specific surface area related elution velocity and physical media characteristics, which...... in this study are performed at a concurrent airflow of 0.3 m s−1, water irrigation rates of 1–21 cm h−1 in materials with particle diameters ranging from 2 to 14 mm to represent media and operation conditions relevant for low flow biotrickling filter design. Specific surface area related elution velocity...... distribution was closely related to the filter water content, water irrigation rate, media specific surface area and particle size distribution. A predictive model linking the specific surface area related elution velocity distribution to irrigation rate, specific surface area and particle size distribution...

  11. Flow enhancement of water flow through silica slit pores with graphene-coated walls

    DEFF Research Database (Denmark)

    Zambrano, Harvey; Wagemann, Enrique; Oyarzua, Elton

    features a unparalleled combination of high specific surface area, chemical stability, mechanical strength and flexibility. Recently, the wettability of water droplets on multilayer graphene sheets deposited on a silica substrate has been investigated. In this study, we investigate the role of graphene......Nanofluidic devices such as Lab-On-a-Chip often are designed to transport water solutions through hydrophilic nano-conduits. In these systems with narrow confinement, the viscous forces dominate the flow and as a result, the hydrodynamic friction drag is very high. Moreover, the drag and the amount...... of energy required for pumping a fluid are directly related. Therefore, it is desirable to explore drag reduction strategies in nanoconfined flows. Liquids are known to slip past non-wetting surfaces. Graphene is a single-atom-thick sheet of carbon atoms arranged in a hexagonal honeycomb lattice, which...

  12. Analyses of flow modification on water quality on Nechako River

    International Nuclear Information System (INIS)

    Mitchell, A.C.; James, C.B.; Edinger, J.E.

    1995-01-01

    Alcan Smelters and Chemicals Ltd. initiated construction of the final phase of the Kemano Completion Project in north-central British Columbia to divert additional water from the Nechako Reservoir to the existing powerhouse. The Nechako Reservoir was created by the construction of the Kenney Dam in Nechako Canyon, a natural barrier to salmon migration. The Nechako River downstream of Nechako Canyon supports important runs of sockeye and chinook salmon. This additional diversion of Nechako River flow creates the potential of high water temperatures and increased thermal stress to migrating sockeye salmon enroute to their spawning grounds in Nechako River tributaries. To achieve specific downstream water temperature objectives during sockeye salmon migration each summer, a two-level outlet facility adjacent to Kenney Dam is to be constructed to release cooling water at 10 C to the Nechako River. Results of mathematical modeling of Nechako River water temperatures show that, based on specified design criteria, a maximum Kenney Dam release of 167 m 3 /s at 10 C would be required to meet the downstream water temperature objectives

  13. Hydro-dynamic damping theory in flowing water

    Science.gov (United States)

    Monette, C.; Nennemann, B.; Seeley, C.; Coutu, A.; Marmont, H.

    2014-03-01

    Fluid-structure interaction (FSI) has a major impact on the dynamic response of the structural components of hydroelectric turbines. On mid-head to high-head Francis runners, the rotor-stator interaction (RSI) phenomenon always has to be considered carefully during the design phase to avoid operational issues later on. The RSI dynamic response amplitudes are driven by three main factors: (1) pressure forcing amplitudes, (2) excitation frequencies in relation to natural frequencies and (3) damping. The prediction of the two first factors has been largely documented in the literature. However, the prediction of fluid damping has received less attention in spite of being critical when the runner is close to resonance. Experimental damping measurements in flowing water on hydrofoils were presented previously. Those results showed that the hydro-dynamic damping increased linearly with the flow. This paper presents development and validation of a mathematical model, based on momentum exchange, to predict damping due to fluid structure interaction in flowing water. The model is implemented as an analytical procedure for simple structures, such as cantilever beams, but is also implemented in more general ways using three different approaches for more complex structures such as runner blades: a finite element procedure, a CFD modal work based approach and a CFD 1DOF approach. The mathematical model and all three implementation approaches are shown to agree well with experimental results.

  14. Unstable fluid flow in a water-cooled heating channel

    International Nuclear Information System (INIS)

    Delayre, R.; Saunier, J.P.

    1961-01-01

    Experimental investigations of the instable behavior of a pressurized water flow in forced convection in a heating channel, with subcooled or bulk boiling have been carried. Tests were conducted at 1140, 850 and 570 psi. The test section was 35 in. high, surmounted by a 25.4 in. riser, these sections were by-passed by a pipe where the flow was between 1 and 4 times the flow in the test section. The water velocity (in the test section) was between 1.6 and 6.6 ft/s. Under certain conditions oscillations with a period of several seconds and perfectly stable have been observed. A mathematical model has been defined and a good agreement obtained for the main characteristics of the oscillations. It seems that the dimensions of the riser have a determining effect: the inception of bulk boiling gives an important variation of the driving head which can generate oscillations due to the non-zero delay for the system to reach its equilibrium. (author) [fr

  15. Distribution flow: a general process in the top layer of water repellent soils

    NARCIS (Netherlands)

    Ritsema, C.J.; Dekker, L.W.

    1995-01-01

    Distribution flow is the process of water and solute flowing in a lateral direction over and through the very first millimetre or centimetre of the soil profile. A potassium bromide tracer was applied in two water-repellent sandy soils to follow the actual flow paths of water and solutes in the

  16. SSDA code to apply data assimilation in soil water flow modeling: Documentation and user manual

    Science.gov (United States)

    Soil water flow models are based on simplified assumptions about the mechanisms, processes, and parameters of water retention and flow. That causes errors in soil water flow model predictions. Data assimilation (DA) with the ensemble Kalman filter (EnKF) corrects modeling results based on measured s...

  17. Environmentally Clean Mitigation of Undesirable Plant Life Using Lasers

    Energy Technology Data Exchange (ETDEWEB)

    Rubenchik, A M; McGrann, T J; Yamamoto, R M; Parker, J M

    2009-07-01

    This concept comprises a method for environmentally clean destruction of undesirable plant life using visible or infrared radiation. We believe that during the blossom stage, plant life is very sensitive to electromagnetic radiation, with an enhanced sensitivity to specific spectral ranges. Small doses of irradiation can arrest further plant growth, cause flower destruction or promote plant death. Surrounding plants, which are not in the blossoming stage, should not be affected. Our proposed mechanism to initiate this effect is radiation produced by a laser. Tender parts of the blossom possess enhanced absorptivity in some spectral ranges. This absorption can increase the local tissue temperature by several degrees, which is sufficient to induce bio-tissue damage. In some instances, the radiation may actually stimulate plant growth, as an alternative for use in increased crop production. This would be dependent on factors such as plant type, the wavelength of the laser radiation being used and the amount of the radiation dose. Practical, economically viable realization of this concept is possible today with the advent of high efficiency, compact and powerful laser diodes. The laser diodes provide an efficient, environmentally clean source of radiation at a variety of power levels and radiation wavelengths. Figure 1 shows the overall concept, with the laser diodes mounted on a movable platform, traversing and directing the laser radiation over a field of opium poppies.

  18. Novel concepts for the containment of oil in flowing water

    International Nuclear Information System (INIS)

    Brown, H.M.; Nicholson, P.; Goodman, R.H.; Berry, B.A.; Hughes, B.R.

    1993-01-01

    Both a laboratory study of the hydrodynamic properties of variously shaped objects and a meso-scale flume study of several containment concepts have been undertaken to determine whether these can be used to contain oil in fast flowing water. The laboratory study showed that stable vortices are difficult to generate and that spilled oil is not easily trapped by them. Only two of the structures studied showed some promise of trapping oil in fast moving water: a partially submerged barrier with fins placed at an angle across the flume and a horizontal hydrofoil placed across the channel near the surface. Several filter materials were tested in an outdoor flowing channel with both floating and neutrally buoyant oil. Although some of these materials trapped and held heavy oil, they were not a significant improvement over nylon fishing nets which had been tested previously. The filter materials would not hold a medium gravity oil. A hydrofoil device which generated a horizontal eddy successfully trapped and held surface oil at water speeds up to 0.35 m/s. Neutrally buoyant oil was often caught by the eddy but was never held for more than 1-2 minutes. 9 refs., 5 figs., 3 tabs

  19. The containment of heavy oil in flowing water

    International Nuclear Information System (INIS)

    Brown, H.M.; Goodman, R.H.; Nicholson, P.

    1992-01-01

    Viscous bitumen from Alberta oil sand deposits is diluted with a gas condensate before pipeline transport. Because of its unique properties, the diluent/bitumen mix (dilbit) may require novel containment and recovery techniques in the case of an accidental spill. Preliminary experiments were conducted in a large flowing water channel to determine whether several conventional containment devices could be utilized to trap weathered and emulsified dilbit and bitumen. These devices included a conventional river boom, a nylon fine-weave net, and a low-pressure bubble barrier. The behavior of the oil samples during boom failure was noted in order to understand more completely the mechanisms of failure. The river boom failed to hold viscous floating oil by vortex shedding at flows of under 0.25 m/s. A fine mesh net successfully trapped both floating and mid-channel neutrally buoyant oil but the retention time depends on the oil viscosity. The bubble barrier was not successful in trapping either floating viscous oil or neutrally buoyant oil. At low water velocities, the barrier was able to divert some oils but in an inconsistent manner. The results indicate that conventional barriers need improvement to be effective at higher water velocities and suggest that new concepts in containment should be considered. 9 refs., 3 figs., 2 tabs

  20. Water flow and solute transport in floating fen root mats

    Science.gov (United States)

    Stofberg, Sija F.; EATM van der Zee, Sjoerd

    2015-04-01

    be very similar and likely functionally related. Our experimental field data were used for modelling water flow and solute transport in floating fens, using HYDRUS 2D. Fluctuations of surface water and root mat, as well as geometry and unsaturated zone parameters can have a major influence on groundwater fluctuations and the exchange between rain and surface water and the water in the root mats. In combination with the duration of salt pulses in surface water, and sensitivity of fen plants to salinity (Stofberg et al. 2014, submitted), risks for rare plants can be anticipated.

  1. Hot-film anemometry in air-water flow

    International Nuclear Information System (INIS)

    Delahaye, J.M.; Galaup, J.P.

    1975-01-01

    Local measurements of void fraction and liquid velocity in a steady-state air-water bubbly flow at atmospheric pressure are presented. Use was made of a constant temperature anemometer and of a conical hot-film probe. The signal was processed with a multi-channel analyzer. Void fraction and liquid velocities are determined from the amplitude histogram of the signal. The integrated void fraction over a diameter is compared with the average void fraction along the same diameter obtained with a γ-ray absorption method. The liquid volumetric flow-rate is calculated from the void fraction and liquid velocity profiles and compared with the indication given by a turbine flowmeter [fr

  2. Visualized investigation on flow regimes for vertical upward steam–water flow in a heated narrow rectangular channel

    International Nuclear Information System (INIS)

    Wang Junfeng; Huang Yanping; Wang Yanlin; Song Mingliang

    2012-01-01

    Highlights: ► Flow regimes were visually investigated in a heated narrow rectangular channel. ► Bubbly, churn, and annular flow were observed. Slug flow was never observed. ► Flow regime transition boundary could be predicted by existing criteria. ► Churn zone in present flow regime maps were poorly predicted by existing criteria. - Abstract: Flow regimes are very important in understanding two-phase flow resistance and heat transfer characteristics. In present work, two-phase flow regimes for steam–water flows in a single-side heated narrow rectangular channel, having a width of 40 mm and a gap of 3 mm, were visually studied at relatively low pressure and low mass flux condition. The flow regimes observed in this experiment could be classified into bubbly, churn and annular flow. Slug flow was never observed at any of the conditions in our experiment. Flow regime maps at the pressure of 0.7 MPa and 1.0 MPa were developed, and then the pressure effect on flow regime transition was analyzed. Based on the experimental results, the comparisons with some existing flow regime maps and transition criteria were conducted. The comparison results show that the bubbly transition boundary and annular formation boundary of heated steam–water flow were consistent with that of adiabatic air–water flow. However, the intermediate flow pattern between bubbly and annular flow was different. Hibiki and Mishima criteria could predict the bubbly transition boundary and annular formation boundary satisfactorily, but it poorly predicted churn zone in present experimental data.

  3. Performance and Flow Field of a Gravitation Vortex Type Water Turbine

    OpenAIRE

    Nishi, Yasuyuki; Inagaki, Terumi

    2017-01-01

    A gravitation vortex type water turbine, which mainly comprises a runner and a tank, generates electricity by introducing a flow of water into the tank and using the gravitation vortex generated when the water drains from the bottom of the tank. This water turbine is capable of generating electricity using a low head and a low flow rate with relatively simple structure. However, because its flow field has a free surface, this water turbine is extremely complicated, and thus its relevance to p...

  4. In-Line Oil-Water Separation in Swirling Flow (USB stick)

    NARCIS (Netherlands)

    Slot, J.J.; van Campen, L.J.A.M.; Hoeijmakers, Hendrik Willem Marie; Mudde, R.F.; Johansen, S.T.

    2011-01-01

    An in-line oil-water separator has been designed and is investigated for single- and two-phase flow. Numerical single-phase flow results show an annular reversed flow region. This flow pattern agrees qualitatively with results from measurements. In the two-phase flow simulations two different drag

  5. A novel drag force coefficient model for gas–water two-phase flows under different flow patterns

    Energy Technology Data Exchange (ETDEWEB)

    Shang, Zhi, E-mail: shangzhi@tsinghua.org.cn

    2015-07-15

    Graphical abstract: - Highlights: • A novel drag force coefficient model was established. • This model realized to cover different flow patterns for CFD. • Numerical simulations were performed under wide range flow regimes. • Validations were carried out through comparisons to experiments. - Abstract: A novel drag force coefficient model has been developed to study gas–water two-phase flows. In this drag force coefficient model, the terminal velocities were calculated through the revised drift flux model. The revised drift flux is different from the traditional drift flux model because the natural curve movement of the bubble was revised through considering the centrifugal force. Owing to the revisions, the revised drift flux model was to extend to 3D. Therefore it is suitable for CFD applications. In the revised drift flux model, the different flow patterns of the gas–water two-phase flows were able to be considered. This model innovatively realizes the drag force being able to cover different flow patterns of gas–water two-phase flows on bubbly flow, slug flow, churn flow, annular flow and mist flow. Through the comparisons of the numerical simulations to the experiments in vertical upward and downward pipe flows, this model was validated.

  6. Compounding Effects of Agricultural Land Use and Water Use in Free-Flowing Rivers: Confounding Issues for Environmental Flows

    Science.gov (United States)

    Hardie, Scott A.; Bobbi, Chris J.

    2018-03-01

    Defining the ecological impacts of water extraction from free-flowing river systems in altered landscapes is challenging as multiple stressors (e.g., flow regime alteration, increased sedimentation) may have simultaneous effects and attributing causality is problematic. This multiple-stressor context has been acknowledged in environmental flows science, but is often neglected when it comes to examining flow-ecology relationships, and setting and implementing environmental flows. We examined the impacts of land and water use on rivers in the upper Ringarooma River catchment in Tasmania (south-east Australia), which contains intensively irrigated agriculture, to support implementation of a water management plan. Temporal and spatial and trends in river condition were assessed using benthic macroinvertebrates as bioindicators. Relationships between macroinvertebrate community structure and environmental variables were examined using univariate and multivariate analyses, focusing on the impacts of agricultural land use and water use. Structural changes in macroinvertebrate communities in rivers in the catchment indicated temporal and spatial declines in the ecological condition of some stretches of river associated with agricultural land and water use. Moreover, water extraction appeared to exacerbate impairment associated with agricultural land use (e.g., reduced macroinvertebrate density, more flow-avoiding taxa). The findings of our catchment-specific bioassessments will underpin decision-making during the implementation of the Ringarooma water management plan, and highlight the need to consider compounding impacts of land and water use in environmental flows and water planning in agricultural landscapes.

  7. Compounding Effects of Agricultural Land Use and Water Use in Free-Flowing Rivers: Confounding Issues for Environmental Flows.

    Science.gov (United States)

    Hardie, Scott A; Bobbi, Chris J

    2018-03-01

    Defining the ecological impacts of water extraction from free-flowing river systems in altered landscapes is challenging as multiple stressors (e.g., flow regime alteration, increased sedimentation) may have simultaneous effects and attributing causality is problematic. This multiple-stressor context has been acknowledged in environmental flows science, but is often neglected when it comes to examining flow-ecology relationships, and setting and implementing environmental flows. We examined the impacts of land and water use on rivers in the upper Ringarooma River catchment in Tasmania (south-east Australia), which contains intensively irrigated agriculture, to support implementation of a water management plan. Temporal and spatial and trends in river condition were assessed using benthic macroinvertebrates as bioindicators. Relationships between macroinvertebrate community structure and environmental variables were examined using univariate and multivariate analyses, focusing on the impacts of agricultural land use and water use. Structural changes in macroinvertebrate communities in rivers in the catchment indicated temporal and spatial declines in the ecological condition of some stretches of river associated with agricultural land and water use. Moreover, water extraction appeared to exacerbate impairment associated with agricultural land use (e.g., reduced macroinvertebrate density, more flow-avoiding taxa). The findings of our catchment-specific bioassessments will underpin decision-making during the implementation of the Ringarooma water management plan, and highlight the need to consider compounding impacts of land and water use in environmental flows and water planning in agricultural landscapes.

  8. Flowing Air-Water Cooled Slab Nd: Glass Laser

    Science.gov (United States)

    Lu, Baida; Cai, Bangwei; Liao, Y.; Xu, Shifa; Xin, Z.

    1989-03-01

    A zig-zag optical path slab geometry Nd: glass laser cooled through flowing air-water is developed by us. Theoretical studies on temperature distribution of slab and rod configurations in the unsteady state clarify the advantages of the slab geometry laser. The slab design and processing are also reported. In our experiments main laser output characteristics, e. g. laser efficiency, polarization, far-field divergence angle as well as resonator misalignment are investigated. The slab phosphate glass laser in combination with a crossed Porro-prism resonator demonstrates a good laser performance.

  9. Experimental study for flow regime of downward air-water two-phase flow in a vertical narrow rectangular channel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, T. H.; Yun, B. J.; Jeong, J. H. [Pusan National University, Geunjeong-gu, Busan (Korea, Republic of)

    2015-05-15

    Studies were mostly about flow in upward flow in medium size circular tube. Although there are great differences between upward and downward flow, studies on vertical upward flow are much more active than those on vertical downward flow in a channel. In addition, due to the increase of surface forces and friction pressure drop, the pattern of gas-liquid two-phase flow bounded to the gap of inside the rectangular channel is different from that in a tube. The downward flow in a rectangular channel is universally applicable to cool the plate type nuclear fuel in research reactor. The sub-channel of the plate type nuclear fuel is designed with a few millimeters. Downward air-water two-phase flow in vertical rectangular channel was experimentally observed. The depth, width, and length of the rectangular channel is 2.35 mm, 66.7 mm, and 780 mm, respectively. The test section consists of transparent acrylic plates confined within a stainless steel frame. The flow patterns of the downward flow in high liquid velocity appeared to be similar to those observed in previous studies with upward flow. In downward flow, the transition lines for bubbly-slug and slug-churn flow shift to left in the flow regime map constructed with abscissa of the superficial gas velocity and ordinate of the superficial liquid velocity. The flow patterns observed with downward flow at low liquid velocity are different from those with upward flow.

  10. Numerical simulation of water and sand blowouts when penetrating through shallow water flow formations in deep water drilling

    Science.gov (United States)

    Ren, Shaoran; Liu, Yanmin; Gong, Zhiwu; Yuan, Yujie; Yu, Lu; Wang, Yanyong; Xu, Yan; Deng, Junyu

    2018-02-01

    In this study, we applied a two-phase flow model to simulate water and sand blowout processes when penetrating shallow water flow (SWF) formations during deepwater drilling. We define `sand' as a pseudo-component with high density and viscosity, which can begin to flow with water when a critical pressure difference is attained. We calculated the water and sand blowout rates and analyzed the influencing factors from them, including overpressure of the SWF formation, as well as its zone size, porosity and permeability, and drilling speed (penetration rate). The obtained data can be used for the quantitative assessment of the potential severity of SWF hazards. The results indicate that overpressure of the SWF formation and its zone size have significant effects on SWF blowout. A 10% increase in the SWF formation overpressure can result in a more than 90% increase in the cumulative water blowout and a 150% increase in the sand blowout when a typical SWF sediment is drilled. Along with the conventional methods of well flow and pressure control, chemical plugging, and the application of multi-layer casing, water and sand blowouts can be effectively reduced by increasing the penetration rate. As such, increasing the penetration rate can be a useful measure for controlling SWF hazards during deepwater drilling.

  11. Unsaturated water flow and tracer transport modeling with Alliances

    Energy Technology Data Exchange (ETDEWEB)

    Constantin, Alina, E-mail: alina.constantin@nuclear.ro [Institute for Nuclear Research, Campului Str, No. 1, PO Box 78, Postal Code 115400 Mioveni, Arges County (Romania); Genty, Alain, E-mail: alain.genty@cea.fr [CEA Saclay, DM2S/SFME/LSE, Gif-sur-Yvette 91191 cedex (France); Diaconu, Daniela; Bucur, Crina [Institute for Nuclear Research, Campului Str, No. 1, PO Box 78, Postal Code 115400 Mioveni, Arges County (Romania)

    2013-12-15

    Highlights: • Simulation of water flow and solute transport at Saligny site, Romania was done. • Computation was based on the available experimental data with Alliances platform. • Very good results were obtained for the saturation profile in steady state. • Close fit to experimental data for saturation profile at 3 m in transient state. • Large dispersivity coefficients were fitted to match tracer experiment. - Abstract: Understanding water flow and solute transport in porous media is of central importance in predicting the radionuclide fate in the geological environment, a topic of interest for the performance and safety assessment studies for nuclear waste disposal. However, it is not easy to predict transport properties in real systems because they are geologically heterogeneous from the pore scale upwards. This paper addresses the simulation of water flow and solute transport in the unsaturated zone of the Saligny site, the potential location for the Romanian low and intermediate level waste (LILW) disposal. Computation was based on the current available experimental data for this zone and was performed within Alliances, a software platform initially jointly developed by French organizations CEA, ANDRA and EDF. The output of the model developed was compared with the measured values in terms of saturation profile of the soil for water movement, in both steady and transient state. Very good results were obtained for the saturation profile in steady state and a close fit of the simulation over experimental data for the water saturation profile at a depth of 3 m in transient state. In order to obtain information regarding the solute migration in depth and the solute lateral dispersion, a tracer test was launched on site and dispersivity coefficients of the solute were fitted in order to match the experimental concentration determined on samples from different locations of the site. Results much close to the experiment were obtained for a longitudinal

  12. Insertable fluid flow passage bridgepiece and method

    Science.gov (United States)

    Jones, Daniel O.

    2000-01-01

    A fluid flow passage bridgepiece for insertion into an open-face fluid flow channel of a fluid flow plate is provided. The bridgepiece provides a sealed passage from a columnar fluid flow manifold to the flow channel, thereby preventing undesirable leakage into and out of the columnar fluid flow manifold. When deployed in the various fluid flow plates that are used in a Proton Exchange Membrane (PEM) fuel cell, bridgepieces of this invention prevent mixing of reactant gases, leakage of coolant or humidification water, and occlusion of the fluid flow channel by gasket material. The invention also provides a fluid flow plate assembly including an insertable bridgepiece, a fluid flow plate adapted for use with an insertable bridgepiece, and a method of manufacturing a fluid flow plate with an insertable fluid flow passage bridgepiece.

  13. Flow and fracture in water-saturated, unconstrained granular beds

    Directory of Open Access Journals (Sweden)

    Germán eVaras

    2015-06-01

    Full Text Available The injection of gas in a liquid-saturated granular bed gives rise to a wide variety of invasion patterns. Many studies have focused on constrained porous media, in which the grains are fixed in the bed and only the interstitial fluid flows when the gas invades the system. With a free upper boundary, however, the grains can be entrained by the ascending gas or fluid motion, and the competition between the upward motion of grains and sedimentation leads to new patterns. We propose a brief review of the experimental investigation of the dynamics of air rising through a water-saturated, unconstrained granular bed, in both two and three dimensions. After describing the invasion pattern at short and long time, a tentative regime-diagram is proposed. We report original results showing a dependence of the fluidized zone shape, at long times, on the injection flow rate and grain size. A method based on image analysis makes it possible to detect not only the fluidized zone profile in the stationary regime, but also to follow the transient dynamics of its formation. Finally, we describe the degassing dynamics inside the fluidized zone, in the stationary regime. Depending on the experimental conditions, regular bubbling, continuous degassing, intermittent regime or even spontaneous flow-to-fracture transition are observed.

  14. Numerical investigations for insulation particle transport phenomena in water flow

    International Nuclear Information System (INIS)

    Krepper, E.; Grahn, A.; Alt, S.; Kaestner, W.; Kratzsch, A.; Seeliger, A.

    2005-01-01

    The investigation of insulation debris generation, transport and sedimentation gains importance regarding the reactor safety research for PWR and BWR considering the long term behaviour of emergency core coolant systems during all types of LOCA. The insulation debris released near the break during LOCA consists of a mixture of very different particles concerning size, shape, consistence and other properties. Some fraction of the released insulation debris will be transported into the reactor sump where it may affect emergency core cooling. Open questions of generic interest are e.g. the sedimentation of the insulation debris in a water pool, possible re-suspension, transport in the sump water flow, particle load on strainers and corresponding difference pressure. A joint research project in cooperation with Institute of Process Technology, Process Automation and Measuring Technology (IPM) Zittau deals with the experimental investigation and the development of CFD models for the description of particle transport phenomena in coolant flow. While experiments are performed at the IPM-Zittau, theoretical work is concentrated at Forschungszentrum Rossendorf. In the present paper the basic concepts for CFD modelling are described and first results including feasibility studies are shown. During the ongoing work further results are expected. (author)

  15. Well-to-Wheels Water Consumption: Tracking the Virtual Flow of Water into Transportation

    Science.gov (United States)

    Lampert, D. J.; Elgowainy, A.; Hao, C.

    2015-12-01

    Water and energy resources are fundamental to life on Earth and essential for the production of consumer goods and services in the economy. Energy and water resources are heavily interdependent—energy production consumes water, while water treatment and distribution consume energy. One example of this so-called energy-water nexus is the consumption of water associated with the production of transportation fuels. The Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model is an analytical tool that can be used to compare the environmental impacts of different transportation fuels on a consistent basis. In this presentation, the expansion of GREET to perform life cycle water accounting or the "virtual flow" of water into transportation and other energy sectors and the associated implications will be discussed. The results indicate that increased usage of alternative fuels may increase freshwater resource consumption. The increased water consumption must be weighed against the benefits of decreased greenhouse gas and fossil energy consumption. Our analysis highlights the importance of regionality, co-product allocation, and consistent system boundaries when comparing the water intensity of alternative transportation fuel production pathways such as ethanol, biodiesel, compressed natural gas, hydrogen, and electricity with conventional petroleum-based fuels such as diesel and gasoline.

  16. Countercurrent air/water and steam/water flow above a perforated plate. Report for October 1978-October 1979

    International Nuclear Information System (INIS)

    Hsieh, C.; Bankoff, S.G.; Tankin, R.S.; Yuen, M.C.

    1980-11-01

    The perforated plate weeping phenomena have been studied in both air/water and steam/cold water systems. The air/water experiment is designed to investigate the effect of geometric factors of the perforated plate on the rate of weeping. A new dimensionless flow rate in the form of H star is suggested. The data obtained are successfully correlated by this H star scaling in the conventional flooding equation. The steam/cold water experiment is concentrated on locating the boundary between weeping and no weeping. The effects of water subcooling, water inlet flow rate, and position of water spray are investigated. Depending on the combination of these factors, several types of weeping were observed. The data obtained at high water spray position can be related to the air/water flooding correlation by replacing the stream flow rate to an effective stream flow rate, which is determined by the mixing efficiency above the plate

  17. Flow of gasoline-in-water microemulsion through water-saturated soil columns

    International Nuclear Information System (INIS)

    Ouyang, Y.; Mansell, R.S.; Rhue, R.D.

    1995-01-01

    Much consideration has been given to the use of surfactants to clean up nonaqueous phase liquids (NAPLs) from contaminated soil and ground water. Although this emulsification technique has shown significant potential for application in environmental remediation practices, a major obstacle leading to low washing efficiency is the potential formation of macroemulsion with unfavorable flow characteristics in porous media. This study investigated influences of the flow of leaded-gasoline-in-water (LG/W) microemulsion upon the transport of gasoline and lead (Pb) species in water-saturated soil columns. Two experiments were performed: (1) the immiscible displacement of leaded gasoline and (2) the miscible displacement of LG/W microemulsion through soil columns, followed by sequentially flushing with NaCl solution and a water/surfactant/cosurfactant (W/S/CoS) mixture. Comparison of breakthrough curves (BTC) for gasoline between the two experiments shows that about 90% of gasoline and total Pb were removed from the soil columns by NaCl solution in the LG/W microemulsion experiment as compared to 40% removal of gasoline and 10% removal of total Pb at the same process in the leaded gasoline experiment. Results indicate that gasoline and Pb species moved much more effectively through soil during miscible flow of LG/W microemulsion than during immiscible flow of leaded gasoline. In contrast to the adverse effects of macroemulsion on the transport of NAPLs, microemulsion was found to enhance the transport of gasoline through water-saturated soil. Mass balance analysis shows that the W/S/CoS mixture had a high capacity for removing residual gasoline and Pb species from contaminated soil. Comparison of water-pressure differences across the soil columns for the two experiments indicates that pore clogging by gasoline droplets was greatly minimized in the LG/W microemulsion experiment

  18. Tangible Landscape: Cognitively Grasping the Flow of Water

    Science.gov (United States)

    Harmon, B. A.; Petrasova, A.; Petras, V.; Mitasova, H.; Meentemeyer, R. K.

    2016-06-01

    Complex spatial forms like topography can be challenging to understand, much less intentionally shape, given the heavy cognitive load of visualizing and manipulating 3D form. Spatiotemporal processes like the flow of water over a landscape are even more challenging to understand and intentionally direct as they are dependent upon their context and require the simulation of forces like gravity and momentum. This cognitive work can be offloaded onto computers through 3D geospatial modeling, analysis, and simulation. Interacting with computers, however, can also be challenging, often requiring training and highly abstract thinking. Tangible computing - an emerging paradigm of human-computer interaction in which data is physically manifested so that users can feel it and directly manipulate it - aims to offload this added cognitive work onto the body. We have designed Tangible Landscape, a tangible interface powered by an open source geographic information system (GRASS GIS), so that users can naturally shape topography and interact with simulated processes with their hands in order to make observations, generate and test hypotheses, and make inferences about scientific phenomena in a rapid, iterative process. Conceptually Tangible Landscape couples a malleable physical model with a digital model of a landscape through a continuous cycle of 3D scanning, geospatial modeling, and projection. We ran a flow modeling experiment to test whether tangible interfaces like this can effectively enhance spatial performance by offloading cognitive processes onto computers and our bodies. We used hydrological simulations and statistics to quantitatively assess spatial performance. We found that Tangible Landscape enhanced 3D spatial performance and helped users understand water flow.

  19. Water Transport and Removal in PEMFC Gas Flow Channel with Various Water Droplet Locations and Channel Surface Wettability

    Directory of Open Access Journals (Sweden)

    Yanzhou Qin

    2018-04-01

    Full Text Available Water transport and removal in the proton exchange membrane fuel cell (PEMFC is critically important to fuel cell performance, stability, and durability. Water emerging locations on the membrane-electrode assembly (MEA surface and the channel surface wettability significantly influence the water transport and removal in PEMFC. In most simulations of water transport and removal in the PEMFC flow channel, liquid water is usually introduced at the center of the MEA surface, which is fortuitous, since water droplet can emerge randomly on the MEA surface in PEMFC. In addition, the commonly used no-slip wall boundary condition greatly confines the water sliding features on hydrophobic MEA/channel surfaces, degrading the simulation accuracy. In this study, water droplet is introduced with various locations along the channel width direction on the MEA surface, and water transport and removal is investigated numerically using an improved model incorporating the sliding flow property by using the shear wall boundary condition. It is found that the water droplet can be driven to the channel sidewall by aerodynamics when the initial water location deviates from the MEA center to a certain amount, forming the water corner flow in the flow channel. The channel surface wettability on the water transport is also studied and is shown to have a significant impact on the water corner flow in the flow channel.

  20. Quantitative imaging of water flow in soil and roots using neutron radiography and deuterated water

    Energy Technology Data Exchange (ETDEWEB)

    Zarebanadkouki, Mohsen

    2013-05-08

    Where and how fast do roots take up water? Despite its importance in plant and soil sciences, there is limited experimental information on the location of water uptake along the roots of transpiring plants growing in soil. The answer to this question requires direct and in-situ measurement of the local flow of water into the roots. The aim of this study was to develop and apply a new method to quantify the local fluxes of water into different segments of the roots of intact plants. To this end, neutron radiography was used to trace the transport of deuterated water (D{sub 2}O) into the roots of lupines. Lupines were grown in aluminum containers filled with sandy soil. The soil was partitioned into different compartments using 1 cm-thick layers of coarse sand as capillary barriers. These barriers limited the diffusion of D{sub 2}O within the soil compartments. D{sub 2}O was locally injected into the selected soil compartments during the day (transpiring plants) and night (non-transpiring plants). Transport of D{sub 2}O into roots was then monitored by neutron radiography with spatial resolution of 100 μm and time intervals of 10 seconds. Neutron radiographs showed that: i) transport of D{sub 2}O into roots was faster during the day than during the night; 2) D{sub 2}O quickly moved along the roots towards the shoots during the day, while at night this axial transport was negligible. The differences between day and night measurements were explained by convective transport of D{sub 2}O into the roots. To quantify the net flow of water into roots, a simple convection-diffusion model was developed, where the increase rate of D{sub 2}O concentration in roots depended on the convective transport (net root water uptake) and the diffusion of D{sub 2}O into roots. The results showed that water uptake was not uniform along the roots. Water uptake was higher in the upper soil layers than in the deeper ones. Along an individual roots, the water uptake rate was higher in the

  1. Quantitative imaging of water flow in soil and roots using neutron radiography and deuterated water

    International Nuclear Information System (INIS)

    Zarebanadkouki, Mohsen

    2013-01-01

    Where and how fast do roots take up water? Despite its importance in plant and soil sciences, there is limited experimental information on the location of water uptake along the roots of transpiring plants growing in soil. The answer to this question requires direct and in-situ measurement of the local flow of water into the roots. The aim of this study was to develop and apply a new method to quantify the local fluxes of water into different segments of the roots of intact plants. To this end, neutron radiography was used to trace the transport of deuterated water (D 2 O) into the roots of lupines. Lupines were grown in aluminum containers filled with sandy soil. The soil was partitioned into different compartments using 1 cm-thick layers of coarse sand as capillary barriers. These barriers limited the diffusion of D 2 O within the soil compartments. D 2 O was locally injected into the selected soil compartments during the day (transpiring plants) and night (non-transpiring plants). Transport of D 2 O into roots was then monitored by neutron radiography with spatial resolution of 100 μm and time intervals of 10 seconds. Neutron radiographs showed that: i) transport of D 2 O into roots was faster during the day than during the night; 2) D 2 O quickly moved along the roots towards the shoots during the day, while at night this axial transport was negligible. The differences between day and night measurements were explained by convective transport of D 2 O into the roots. To quantify the net flow of water into roots, a simple convection-diffusion model was developed, where the increase rate of D 2 O concentration in roots depended on the convective transport (net root water uptake) and the diffusion of D 2 O into roots. The results showed that water uptake was not uniform along the roots. Water uptake was higher in the upper soil layers than in the deeper ones. Along an individual roots, the water uptake rate was higher in the proximal segments than in the distal

  2. Continuous-flow solar UVB disinfection reactor for drinking water.

    Science.gov (United States)

    Mbonimpa, Eric Gentil; Vadheim, Bryan; Blatchley, Ernest R

    2012-05-01

    Access to safe, reliable sources of drinking water is a long-standing problem among people in developing countries. Sustainable solutions to these problems often involve point-of-use or community-scale water treatment systems that rely on locally-available resources and expertise. This philosophy was used in the development of a continuous-flow, solar UVB disinfection system. Numerical modeling of solar UVB spectral irradiance was used to define temporal variations in spectral irradiance at several geographically-distinct locations. The results of these simulations indicated that a solar UVB system would benefit from incorporation of a device to amplify ambient UVB fluence rate. A compound parabolic collector (CPC) was selected for this purpose. Design of the CPC was based on numerical simulations that accounted for the shape of the collector and reflectance. Based on these simulations, a prototype CPC was constructed using materials that would be available and inexpensive in many developing countries. A UVB-transparent pipe was positioned in the focal area of the CPC; water was pumped through the pipe to allow exposure of waterborne microbes to germicidal solar UVB radiation. The system was demonstrated to be effective for inactivation of Escherichia coli, and DNA-weighted UV dose was shown to govern reactor performance. The design of the reactor is expected to scale linearly, and improvements in process performance (relative to results from the prototype) can be expected by use of larger CPC geometry, inclusion of better reflective materials, and application in areas with greater ambient solar UV spectral irradiance than the location of the prototype tests. The system is expected to have application for water treatment among communities in (developing) countries in near-equatorial and tropical locations. It may also have application for disaster relief or military field operations, as well as in water treatment in areas of developed countries that receive

  3. Stochastic analysis of unsaturated steady flows above the water table

    Science.gov (United States)

    Severino, Gerardo; Scarfato, Maddalena; Comegna, Alessandro

    2017-08-01

    Steady flow takes place into a three-dimensional partially saturated porous medium where, due to their spatial variability, the saturated conductivity Ks, and the relative conductivity Kr are modeled as random space functions (RSF)s. As a consequence, the flow variables (FVs), i.e., pressure-head and specific flux, are also RSFs. The focus of the present paper consists into quantifying the uncertainty of the FVs above the water table. The simple expressions (most of which in closed form) of the second-order moments pertaining to the FVs allow one to follow the transitional behavior from the zone close to the water table (where the FVs are nonstationary), till to their far-field limit (where the FVs become stationary RSFs). In particular, it is shown how the stationary limits (and the distance from the water table at which stationarity is attained) depend upon the statistical structure of the RSFs Ks, Kr, and the infiltrating rate. The mean pressure head >> has been also computed, and it is expressed as =Ψ0>(1+ψ>), being ψ a characteristic heterogeneity function which modifies the zero-order approximation Ψ0 of the pressure head (valid for a vadose zone of uniform soil properties) to account for the spatial variability of Ks and Kr. Two asymptotic limits, i.e., close (near field) and away (far field) from the water table, are derived into a very general manner, whereas the transitional behavior of ψ between the near/far field can be determined after specifying the shape of the various input soil properties. Besides the theoretical interest, results of the present paper are useful for practical purposes, as well. Indeed, the model is tested against to real data, and in particular it is shown how it is possible for the specific case study to grasp the behavior of the FVs within an environment (i.e., the vadose zone close to the water table) which is generally very difficult to access by direct inspection.

  4. Complex network analysis of phase dynamics underlying oil-water two-phase flows

    Science.gov (United States)

    Gao, Zhong-Ke; Zhang, Shan-Shan; Cai, Qing; Yang, Yu-Xuan; Jin, Ning-De

    2016-01-01

    Characterizing the complicated flow behaviors arising from high water cut and low velocity oil-water flows is an important problem of significant challenge. We design a high-speed cycle motivation conductance sensor and carry out experiments for measuring the local flow information from different oil-in-water flow patterns. We first use multivariate time-frequency analysis to probe the typical features of three flow patterns from the perspective of energy and frequency. Then we infer complex networks from multi-channel measurements in terms of phase lag index, aiming to uncovering the phase dynamics governing the transition and evolution of different oil-in-water flow patterns. In particular, we employ spectral radius and weighted clustering coefficient entropy to characterize the derived unweighted and weighted networks and the results indicate that our approach yields quantitative insights into the phase dynamics underlying the high water cut and low velocity oil-water flows. PMID:27306101

  5. Water circulation in non-isothermal droplet-laden turbulent channel flow

    NARCIS (Netherlands)

    Russo, E; Kuerten, Johannes G.M.; van der Geld, C.W.M.; Geurts, Bernardus J.; Simos, T.; Psihoyios, G.; Tsitouras, Ch.

    2013-01-01

    We propose a point-particle model for two-way coupling of water droplets dispersed in turbulent flow of a carrier gas consisting of air and water vapor. An incompressible flow formulation is applied for direct numerical simulation (DNS) of turbulent channel flow with a warm and a cold wall. Compared

  6. A Potential Approach for Low Flow Selection in Water Resource Supply and Management

    Science.gov (United States)

    Ying Ouyang

    2012-01-01

    Low flow selections are essential to water resource management, water supply planning, and watershed ecosystem restoration. In this study, a new approach, namely the frequent-low (FL) approach (or frequent-low index), was developed based on the minimum frequent-low flow or level used in minimum flows and/or levels program in northeast Florida, USA. This FL approach was...

  7. Air-water flow in a vertical pipe with sudden changes of superficial water velocity

    International Nuclear Information System (INIS)

    Horst-Michael Prasser; Eckhard Krepper; Thomas Frank

    2005-01-01

    Full text of publication follows: For further model development and the validation of CFD codes for two-phase flow applications experiments were carried out with a sudden change of the superficial velocity of water. The tests were performed in a vertical pipe of 51.2 mm diameter. The gas was injected through 19 capillaries of 0.8 mm inner diameter equally distributed over the cross section of the pipe. Measurements were taken by two wire-mesh sensors (24 x 24 points, 2500 Hz) mounted in a short distance (16 mm) behind each other. This sensor assembly was placed 3030 mm downstream of the gas injection. The change of the superficial water velocity was produced by a butterfly valve, the flap of which was perforated. In this way, a rapid closure of the valve caused a jump-like reduction of the liquid flow rate. The valve was located upstream of the gas injection. In a second series of tests a jump-like increase of the water flow rate was studied. Time sequences of the gas fraction profile were calculated from the wire-mesh sensor data over sampling periods of 0.2 s per profile. To increase the statistical reliability of the data, the transient was repeated several times and the data superposed (ensemble averaging). Gas velocity distributions were determined by correlation of the signals with the measurements of the second sensor. The tests enable the observation of the restructuring process of bubbly flow between two steady state conditions. The process is subdivided into three main stages: (1) the undisturbed flow before the velocity jump, (2) the passage of the bubbly flow formed under initial conditions, but travelling with the new velocity and (3) the bubbly flow generated under the new boundary conditions. Transient behaviour between these stages is reflected by the measured data. Special attention was paid to stage 2, where the radial gas fraction profiles change shape due to the excitation of the force balance acting on the bubbles. The experimental results for

  8. Groundwater flow cycling between a submarine spring and an inland fresh water spring.

    Science.gov (United States)

    Davis, J Hal; Verdi, Richard

    2014-01-01

    Spring Creek Springs and Wakulla Springs are large first magnitude springs that derive water from the Upper Floridan Aquifer. The submarine Spring Creek Springs are located in a marine estuary and Wakulla Springs are located 18 km inland. Wakulla Springs has had a consistent increase in flow from the 1930s to the present. This increase is probably due to the rising sea level, which puts additional pressure head on the submarine Spring Creek Springs, reducing its fresh water flow and increasing flows in Wakulla Springs. To improve understanding of the complex relations between these springs, flow and salinity data were collected from June 25, 2007 to June 30, 2010. The flow in Spring Creek Springs was most sensitive to rainfall and salt water intrusion, and the flow in Wakulla Springs was most sensitive to rainfall and the flow in Spring Creek Springs. Flows from the springs were found to be connected, and composed of three repeating phases in a karst spring flow cycle: Phase 1 occurred during low rainfall periods and was characterized by salt water backflow into the Spring Creek Springs caves. The higher density salt water blocked fresh water flow and resulted in a higher equivalent fresh water head in Spring Creek Springs than in Wakulla Springs. The blocked fresh water was diverted to Wakulla Springs, approximately doubling its flow. Phase 2 occurred when heavy rainfall resulted in temporarily high creek flows to nearby sinkholes that purged the salt water from the Spring Creek Springs caves. Phase 3 occurred after streams returned to base flow. The Spring Creek Springs caves retained a lower equivalent fresh water head than Wakulla Springs, causing them to flow large amounts of fresh water while Wakulla Springs flow was reduced by about half. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

  9. Effects of alloy composition and flow condition on the flow accelerated corrosion in neutral water condition

    International Nuclear Information System (INIS)

    Satoh, Tomonori; Ugachi, Hirokazu; Tsukada, Takashi; Uchida, Shunsuke

    2008-01-01

    The major mechanism of Flow accelerated corrosion (FAC) is the dissolution of the protective oxide on carbon steel, which is enhanced by mass transfer and erosion under high flow velocity conditions. In this study, the effects of alloy composition and flow velocity on FAC of carbon steel were evaluated by measuring FAC rate of tube type carbon steel specimens in the neutral water condition at 150degC. Obtained results are summarized in follows. 1) High FAC rate was depended upon the v 1.2 in the tube type specimen made of the standard alloy. 2) FAC was mitigated for the carbon steel with more than 0.03% of Cr content. 3) FAC rate decreased as Ni content increased in more than 0.1% of Ni content. 4) The difference in chemical composition of oxide film between Ni added carbon steel and Cr added one was confirmed. The hematite rich oxide was observed for Ni added carbon steel. 5) The effects of Cu on FAC rate was not observed up to 0.1% of Cu content. (author)

  10. Documentation of the Santa Clara Valley regional ground-water/surface-water flow model, Santa Clara Valley, California

    Science.gov (United States)

    Hanson, R.T.; Li, Zhen; Faunt, C.C.

    2004-01-01

    The Santa Clara Valley is a long, narrow trough extending about 35 miles southeast from the southern end of San Francisco Bay where the regional alluvial-aquifer system has been a major source of water. Intensive agricultural and urban development throughout the 20th century and related ground-water development resulted in ground-water-level declines of more than 200 feet and land subsidence of as much as 12.7 feet between the early 1900s and the mid-1960s. Since the 1960s, Santa Clara Valley Water District has imported surface water to meet growing demands and reduce dependence on ground-water supplies. This importation of water has resulted in a sustained recovery of the ground-water flow system. To help support effective management of the ground-water resources, a regional ground-water/surface-water flow model was developed. This model simulates the flow of ground water and surface water, changes in ground-water storage, and related effects such as land subsidence. A numerical ground-water/surface-water flow model of the Santa Clara Valley subbasin of the Santa Clara Valley was developed as part of a cooperative investigation with the Santa Clara Valley Water District. The model better defines the geohydrologic framework of the regional flow system and better delineates the supply and demand components that affect the inflows to and outflows from the regional ground-water flow system. Development of the model includes revisions to the previous ground-water flow model that upgraded the temporal and spatial discretization, added source-specific inflows and outflows, simulated additional flow features such as land subsidence and multi-aquifer wellbore flow, and extended the period of simulation through September 1999. The transient-state model was calibrated to historical surface-water and ground-water data for the period 197099 and to historical subsidence for the period 198399. The regional ground-water flow system consists of multiple aquifers that are grouped

  11. Use of multiple water surface flow constructed wetlands for non-point source water pollution control.

    Science.gov (United States)

    Li, Dan; Zheng, Binghui; Liu, Yan; Chu, Zhaosheng; He, Yan; Huang, Minsheng

    2018-05-02

    Multiple free water surface flow constructed wetlands (multi-FWS CWs) are a variety of conventional water treatment plants for the interception of pollutants. This review encapsulated the characteristics and applications in the field of ecological non-point source water pollution control technology. The roles of in-series design and operation parameters (hydraulic residence time, hydraulic load rate, water depth and aspect ratio, composition of influent, and plant species) for performance intensification were also analyzed, which were crucial to achieve sustainable and effective contaminants removal, especially the retention of nutrient. The mechanism study of design and operation parameters for the removal of nitrogen and phosphorus was also highlighted. Conducive perspectives for further research on optimizing its design/operation parameters and advanced technologies of ecological restoration were illustrated to possibly interpret the functions of multi-FWS CWs.

  12. Modeling Surface Water Flow in the Atchafalaya Basin

    Science.gov (United States)

    Liu, K.; Simard, M.

    2017-12-01

    While most of the Mississippi River Delta is sinking due to insufficient sediment supply and subsidence, the stable wetlands and the prograding delta systems in the Atchafalaya Basin provide a unique opportunity to study the constructive interactions between riverine and marine forcings and their impacts upon coastal morphology. To better understand the hydrodynamics in this region, we developed a numerical modeling system for the water flow through the river channel - deltas - wetlands networks in the Atchafalaya Basin. Determining spatially varying model parameters for a large area composed of such diverse land cover types poses a challenge to developing an accurate numerical model. For example, the bottom friction coefficient can not be measured directly and the available elevation maps for the wetlands in the basin are inaccurate. To overcome these obstacles, we developed the modeling system in three steps. Firstly, we modeled river bathymetry based on in situ sonar transects and developed a simplified 1D model for the Wax Lake Outlet using HEC-RAS. Secondly, we used a Bayesian approach to calibrate the model automatically and infer important unknown parameters such as riverbank elevation and bottom friction coefficient through Markov Chain Monte Carlo (MCMC) simulations. We also estimated the wetland elevation based on the distribution of different vegetation species in the basin. Thirdly, with the lessons learnt from the 1D model, we developed a depth-averaged 2D model for the whole Atchafalaya Basin using Delft3D. After calibrations, the model successfully reproduced the water levels measured at five gauges in the Wax Lake Outlet and the modeled water surface profile along the channel agreed reasonably well with our LIDAR measurements. In addition, the model predicted a one-hour delay in tidal phase from the Wax Lake Delta to the upstream gauge. In summary, this project presents a procedure to initialize hydrology model parameters that integrates field

  13. FEWA: a Finite Element model of Water flow through Aquifers

    International Nuclear Information System (INIS)

    Yeh, G.T.; Huff, D.D.

    1983-11-01

    This report documents the implementation and demonstration of a Finite Element model of Water flow through Aquifers (FEWA). The particular features of FEWA are its versatility and flexibility to deal with as many real-world problems as possible. Point as well as distributed sources/sinks are included to represent recharges/pumpings and rainfall infiltrations. All sources/sinks can be transient or steady state. Prescribed hydraulic head on the Dirichlet boundaries and fluxes on Neumann or Cauchy boundaries can be time-dependent or constant. Source/sink strength over each element and node, hydraulic head at each Dirichlet boundary node, and flux at each boundary segment can vary independently of each other. Either completely confined or completely unconfined aquifers, or partially confined and partially unconfined aquifers can be dealt with effectively. Discretization of a compound region with very irregular curved boundaries is made easy by including both quadrilateral and triangular elements in the formulation. Large-field problems can be solved efficiently by including a pointwise iterative solution strategy as an optional alternative to the direct elimination solution method for the matrix equation approximating the partial differential equation of groundwater flow. FEWA also includes transient flow through confining leaky aquifers lying above and/or below the aquifer of interest. The model is verified against three simple cases to which analytical solutions are available. It is then demonstrated by two examples of how the model can be applied to heterogeneous and anisotropic aquifers with transient boundary conditions, time-dependent sources/sinks, and confining aquitards for a confined aquifer of variable thickness and for a free surface problem in an unconfined aquifer, respectively. 20 references, 25 figures, 8 tables

  14. FEWA: a Finite Element model of Water flow through Aquifers

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, G.T.; Huff, D.D.

    1983-11-01

    This report documents the implementation and demonstration of a Finite Element model of Water flow through Aquifers (FEWA). The particular features of FEWA are its versatility and flexibility to deal with as many real-world problems as possible. Point as well as distributed sources/sinks are included to represent recharges/pumpings and rainfall infiltrations. All sources/sinks can be transient or steady state. Prescribed hydraulic head on the Dirichlet boundaries and fluxes on Neumann or Cauchy boundaries can be time-dependent or constant. Source/sink strength over each element and node, hydraulic head at each Dirichlet boundary node, and flux at each boundary segment can vary independently of each other. Either completely confined or completely unconfined aquifers, or partially confined and partially unconfined aquifers can be dealt with effectively. Discretization of a compound region with very irregular curved boundaries is made easy by including both quadrilateral and triangular elements in the formulation. Large-field problems can be solved efficiently by including a pointwise iterative solution strategy as an optional alternative to the direct elimination solution method for the matrix equation approximating the partial differential equation of groundwater flow. FEWA also includes transient flow through confining leaky aquifers lying above and/or below the aquifer of interest. The model is verified against three simple cases to which analytical solutions are available. It is then demonstrated by two examples of how the model can be applied to heterogeneous and anisotropic aquifers with transient boundary conditions, time-dependent sources/sinks, and confining aquitards for a confined aquifer of variable thickness and for a free surface problem in an unconfined aquifer, respectively. 20 references, 25 figures, 8 tables.

  15. Flow loop studies with AMAX coal-water mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Wildman, D.J.; Ekmann, J.M.

    1984-03-01

    The coal-water mixtures (CWM) with a stabilizer and the CWM without stabilizers were successfully transported through a flow loop facility under a variety of conditions. The handling characteristics of both CWM were reasonable. The mix tank mixer was not needed during nontesting hours to prevent settling of either material. After several days of transporting the nonstabilized material in the loop facility, the viscosity-reducing agent became ineffective. It was necessary to increase the concentration of the viscosity-reducing agent. The material with stabilizer could not be transported through the loop facility at mass flow rates greater than 209 lb/min until overnight shearing of the CWM in the tank. The CWM without a stabilizer appeared to be slightly shear-thickening, whereas the stabilized CWM initially exhibited shear-thinning behavior. The pressure losses measured for the nonstabilized material were similar to the pressure losses measured for CWM prepared at PETC with three or four percent higher concentration of Pittsburgh seam coal. Tests performed with the stabilized CWM experienced pressure losses similar to CWM prepared at PETC with Pittsburgh seam coal of five to seven percent higher concentration. Tests 1A, 2A, 1B, and 2B were not included in the comparison of in-house-prepared CWM due to differences in pretest handling procedures. 1 figure, 2 tables.

  16. Large-eddy simulations of unidirectional water flow over dunes

    Science.gov (United States)

    Grigoriadis, D. G. E.; Balaras, E.; Dimas, A. A.

    2009-06-01

    The unidirectional, subcritical flow over fixed dunes is studied numerically using large-eddy simulation, while the immersed boundary method is implemented to incorporate the bed geometry. Results are presented for a typical dune shape and two Reynolds numbers, Re = 17,500 and Re = 93,500, on the basis of bulk velocity and water depth. The numerical predictions of velocity statistics at the low Reynolds number are in very good agreement with available experimental data. A primary recirculation region develops downstream of the dune crest at both Reynolds numbers, while a secondary region develops at the toe of the dune crest only for the low Reynolds number. Downstream of the reattachment point, on the dune stoss, the turbulence intensity in the developing boundary layer is weaker than in comparable equilibrium boundary layers. Coherent vortical structures are identified using the fluctuating pressure field and the second invariant of the velocity gradient tensor. Vorticity is primarily generated at the dune crest in the form of spanwise "roller" structures. Roller structures dominate the flow dynamics near the crest, and are responsible for perturbing the boundary layer downstream of the reattachment point, which leads to the formation of "horseshoe" structures. Horseshoe structures dominate the near-wall dynamics after the reattachment point, do not rise to the free surface, and are distorted by the shear layer of the next crest. The occasional interaction between roller and horseshoe structures generates tube-like "kolk" structures, which rise to the free surface and persist for a long time before attenuating.

  17. Microcomputer-controlled flow meter used on a water loop

    International Nuclear Information System (INIS)

    Haniger, L.

    1982-01-01

    The report describes a microcomputer-controlled instrument intended for operational measurement on an experimental water loop. On the basis of pressure and temperature input signals the instrument calculates the specific weight, and for ten operator-selectable measuring channels it calculates the mass flow G(kp/s), or the voluminal flow Q(m 3 /h). On pressing the appropriate push-buttons the built-in display indicates the values of pressure (p) and temperature (t), as well as the values of specific weight γ calculated therefrom. For ten individually selectable channels the instrument displays either the values of the pressure differences of the measuring throttling elements (√Δpsub(i)), or the values of Gsub(i) or Qsub(i) as obtained by calculation. In addition, on pressing the Σ-push-button it summarizes the values of Gsub(i) and Qsub(i) for the selected channels. The device is controlled by an 8085 microprocessor, the analog unit MP 6812 being used as the A/D convertor. The instrument algorithm indicates some possible errors which may concern faults of input signals or mistakes in calculation. (author)

  18. 77 FR 74449 - Water Quality Standards for the State of Florida's Lakes and Flowing Waters; Proposed Rule; Stay

    Science.gov (United States)

    2012-12-14

    ... Water Quality Standards for the State of Florida's Lakes and Flowing Waters; Proposed Rule; Stay AGENCY... Protection Agency (EPA) proposes to temporarily stay our regulation the ``Water Quality Standards for the... Information Does this action apply to me? Citizens concerned with water quality in Florida may be interested...

  19. Estimates of the impacts of invasive alien plants on water flows in ...

    African Journals Online (AJOL)

    The adverse impacts of alien plant invasions on water flows have been a prime motivation for South Africa's Working for Water Programme. The approach used in this study builds on a previous national assessment in 1998 by incorporating factors that limit plant water-use, information from recent research and improved flow ...

  20. Two-phase air-water stratified flow measurement using ultrasonic techniques

    International Nuclear Information System (INIS)

    Fan, Shiwei; Yan, Tinghu; Yeung, Hoi

    2014-01-01

    In this paper, a time resolved ultrasound system was developed for investigating two-phase air-water stratified flow. The hardware of the system includes a pulsed wave transducer, a pulser/receiver, and a digital oscilloscope. The time domain cross correlation method is used to calculate the velocity profile along ultrasonic beam. The system is able to provide velocities with spatial resolution of around 1mm and the temporal resolution of 200μs. Experiments were carried out on single phase water flow and two-phase air-water stratified flow. For single phase water flow, the flow rates from ultrasound system were compared with those from electromagnetic flow (EM) meter, which showed good agreement. Then, the experiments were conducted on two-phase air-water stratified flow and the results were given. Compared with liquid height measurement from conductance probe, it indicated that the measured velocities were explainable

  1. Compartment in vertical flow reactor for ferruginous mine water

    Science.gov (United States)

    Hur, Won; Cheong, Young-Wook; Yim, Gil-Jae; Ji, Sang-Woo; Hong, Ji-Hye

    2014-05-01

    Mine effluents contain varying concentrations of ferrous ion along with other metal ions. Fe(II) that quickly oxidizes to form precipitates in the presence of oxygen under net alkaline or neutral conditions. Thus, passive treatment methods are designed for the mine water to reside in an open containment area so as to allow simultaneous oxidation and precipitation of Fe(II), such as in a lagoon or an oxidation pond. A vertical flow reactor (VFR) was also suggested to remediate ferruginous mine drainage passing down through an accreting bed of ochre. However, VFR has a limited operation time until the system begins to overflow. It was also demonstrated that two-compartment VFR has a longer operation time than single compartment VFR of same size. In this study, a mathematical model was developed as a part of efforts to explore the operation of VFR, showing dynamic changes in head differences, ochre depth and Fe(II)/Fe(III) concentration in the effluent flow. The analysis shows that Fe(II) oxidation and ochre formation should be balanced with permeability of ochre bed to maximize VFR operation time and minimize residual Fe(II) in the effluent. The model demonstrates that two compartment VFR can have a longer operation time than a single-compartment VFR and that an optimum compartment ratio exists that maximize VFR operation time. Accelerated Fe(II) oxidation significantly affects the optimum ratio of compartment area and reduced residual Fe(II) in the effluent. VFR operation time can be significantly prolonged by increasing the rate of ochre formation not by accelerated Fe(II) oxidation. Taken together, ochre forms largely in the first compartment while overflowed mine water with reduced iron contents is efficiently filtered in the second compartment. These results provide us a better understanding of VFR operation and optimum design criteria for maximum operation time in a two-compartment VFR. Rapid ochre accretion in the first compartment maintains constant hydraulic

  2. Assessment of interstate virtual water flows embedded in agriculture to mitigate water scarcity in India (1996-2014)

    Science.gov (United States)

    Katyaini, Suparana; Barua, Anamika

    2017-08-01

    India is the largest global freshwater user despite being highly water scarce. Agriculture is largest consumer of water and is most affected by water scarcity. Water scarcity is a persistent challenge in India, due to a gap in science and policy spheres. Virtual Water (VW) flows concept to mitigate water scarcity is at the science-policy interface. The paper aims to address the gap in VW research in India by first analyzing the interstate VW-flows embedded in food grains, and then linking these VW-flows with the water scarcity situation in the states, and elements of state and national water policies for the postreforms, and recovery periods of India's agriculture. There were net water savings (WS) of 207.5 PL during 1996-2014, indicating sustainable flows at the national level. WS increased from 11.2 TL/yr (1996-2005) to 25931.7 TL/yr (2005-2014), with the increase in interstate movement of food grains, and yield. However, unsustainable flows are seen at subnational scale, as VW-flows are from highly water-scarce states in North to highly water-scarce states in West and South. These flows are causing a concentration of water scarcity in water-scarce zones/states. Net VW imports were found to be driven by larger population and net VW exports by arable land. Further, the absence of state water policy cripples water management. Therefore, the paper argues that there is a need to rethink policy decisions on agriculture at the national and state level by internalizing water as a factor of production, through VW research.

  3. Effects of virtual water flow on regional water resources stress: A case study of grain in China.

    Science.gov (United States)

    Sun, Shikun; Wang, Yubao; Engel, Bernie A; Wu, Pute

    2016-04-15

    Scarcity of water resources is one of the major challenges in the world, particularly for the main water consumer, agriculture. Virtual water flow (VWF) promotes water redistribution geographically and provides a new solution for resolving regional water shortage and improving water use efficiency in the world. Virtual water transfer among regions will have a significant influence on the water systems in both grain export and import regions. In order to assess the impacts of VWF related grain transfer on regional water resources conditions, the study takes mainland China as study area for a comprehensive evaluation of virtual water flow on regional water resources stress. Results show that Northeast China and Huang-Huai-Hai region are the major grain production regions as well as the major virtual water export regions. National water savings related to grain VWF was about 58Gm(3), with 48Gm(3) blue water and 10Gm(3) green water. VWF changes the original water distribution and has a significant effect on water resources in both virtual water import and export regions. Grain VWF significantly increased water stress in grain export regions and alleviated water stress in grain import regions. Water stress index (WSI) of Heilongjiang and Inner Mongolia has been increased by 138% and 129% due to grain export. Stress from water shortages is generally severe in export regions, and issues with the sustainability of grain production and VWF pattern are worthy of further exploration. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Research on the flow field of undershot cross-flow water turbines using experiments and numerical analysis

    International Nuclear Information System (INIS)

    Nishi, Y; Inagaki, T; Li, Y; Omiya, R; Hatano, K

    2014-01-01

    The purpose of this research is to develop a water turbine appropriate for low-head open channels in order to effectively utilize the unused hydropower energy of rivers and agricultural waterways. The application of the cross-flow runner to open channels as an undershot water turbine has come under consideration and, to this end, a significant simplification was attained by removing the casings. However, the flow field of undershot cross-flow water turbines possesses free surfaces. This means that with the variation in the rotational speed, the water depth around the runner will change and flow field itself is significantly altered. Thus it is necessary to clearly understand the flow fields with free surfaces in order to improve the performance of this turbine. In this research, the performance of this turbine and the flow field were studied through experiments and numerical analysis. The experimental results on the performance of this turbine and the flow field were consistent with the numerical analysis. In addition, the inlet and outlet regions at the first and second stages of this water turbine were clarified

  5. Analytical Model of Water Flow in Coal with Active Matrix

    Science.gov (United States)

    Siemek, Jakub; Stopa, Jerzy

    2014-12-01

    This paper presents new analytical model of gas-water flow in coal seams in one dimension with emphasis on interactions between water flowing in cleats and coal matrix. Coal as a flowing system, can be viewed as a solid organic material consisting of two flow subsystems: a microporous matrix and a system of interconnected macropores and fractures. Most of gas is accumulated in the microporous matrix, where the primary flow mechanism is diffusion. Fractures and cleats existing in coal play an important role as a transportation system for macro scale flow of water and gas governed by Darcy's law. The coal matrix can imbibe water under capillary forces leading to exchange of mass between fractures and coal matrix. In this paper new partial differential equation for water saturation in fractures has been formulated, respecting mass exchange between coal matrix and fractures. Exact analytical solution has been obtained using the method of characteristics. The final solution has very simple form that may be useful for practical engineering calculations. It was observed that the rate of exchange of mass between the fractures and the coal matrix is governed by an expression which is analogous to the Newton cooling law known from theory of heat exchange, but in present case the mass transfer coefficient depends not only on coal and fluid properties but also on time and position. The constant term of mass transfer coefficient depends on relation between micro porosity and macro porosity of coal, capillary forces, and microporous structure of coal matrix. This term can be expressed theoretically or obtained experimentally. W artykule zaprezentowano nowy model matematyczny przepływu wody i gazu w jednowymiarowej warstwie węglowej z uwzględnieniem wymiany masy między systemem szczelin i matrycą węglową. Węgiel jako system przepływowy traktowany jest jako układ o podwójnej porowatości i przepuszczalności, składający się z mikroporowatej matrycy węglowej oraz z

  6. Water temperature in irrigation return flow from the Upper Snake Rock watershed

    Science.gov (United States)

    Water returning to a river from an irrigated watershed could increase the water temperature in the river. The objective of this study was to compare the temperature of irrigation return flow water with the temperature of the diverted irrigation water. Water temperature was measured weekly in the mai...

  7. A test section design to simulate horizontal two-phase air-water flow

    International Nuclear Information System (INIS)

    Faccini, Jose Luiz H.; Cesar, Silvia B.G.; Coutinho, Jorge A.; Freitas, Sergio Carlos; Addor, Pedro N.

    2002-01-01

    In this work an air-water two-phase flow horizontal test section assembling at Nuclear Engineering Institute (IEN) is presented. The test section was designed to allow four-phase flow patterns to be simulated: bubble flow, stratified flow, wave flow and slug flow. These flow patterns will be identified by non-conventional ultrasonic techniques which have been developed to meet this particular application. Based on the separated flow and drift-flux models the test section design steps are shown. A description of the test section and its instrumentation and data acquisition system is also provided. (author)

  8. Patterns of a slow air-water flow in a semispherical container

    DEFF Research Database (Denmark)

    Balci, Adnan; Brøns, Morten; Herrada, Miguel A.

    2016-01-01

    This numerical study analyzes the development of eddies in a slow steady axisymmetric air-water flow in a sealed semispherical container, driven by a rotating top disk. As the water height, Hw, increases, new flow cells emerge in both water and air. First, an eddy emerges near the axis-bottom int......This numerical study analyzes the development of eddies in a slow steady axisymmetric air-water flow in a sealed semispherical container, driven by a rotating top disk. As the water height, Hw, increases, new flow cells emerge in both water and air. First, an eddy emerges near the axis...... on the air flow. In contrast to flows in cylindrical and conical containers, there is no interaction with Moffatt corner vortices here....

  9. Pitot tube and drag body measurements in transient steam--water flows

    International Nuclear Information System (INIS)

    Fincke, J.R.; Deason, V.A.; Dacus, M.W.

    1979-01-01

    The use of full-flow drag devices and rakes of water-cooled Pitot tubes to measure the transient two-phase mass flow during loss-of-coolant experiments in pressurized water reactor (PWR) environments has been developed. Mass flow rate measurements have been obtained in high temperature and pressure environments, similar to PWRs, under transient conditions. Comparisons of the measured time integrated value of mass flow to the known system mass before depressurization are made

  10. Qualitative screening of undesirable compounds from feeds to fish by liquid chromatography coupled to mass spectrometry.

    Science.gov (United States)

    Nácher-Mestre, Jaime; Ibáñez, María; Serrano, Roque; Pérez-Sánchez, Jaume; Hernández, Félix

    2013-03-06

    This paper describes the development, validation, and application of a rapid screening method for the detection and identification of undesirable organic compounds in aquaculture products. A generic sample treatment was applied without any purification or preconcentration step. After extraction of the samples with acetonitrile/water 80:20 (0.1% formic acid), the extracts were centrifuged and directly injected in the LC-HRMS system, consisting of ultra-high performance liquid chromatography coupled to hybrid quadrupole time-of-flight mass spectrometry (UHPLC-QTOF MS). A qualitative validation was carried out for over 70 representative compounds, including antibiotics, pesticides, and mycotoxins, in fish feed and fish fillets spiked at 20 and 100 μg/kg. At the highest level, the great majority of compounds were detected (using the most abundant ion, typically the protonated molecule) and unequivocally identified (on the basis of the presence of two accurate-mass measured ions). At the 20 μg/kg level, many contaminants could already be detected, although identification using two ions was not fully reached for some of them, mainly in fish feed due to the complexity of this matrix. Subsequent application of this screening methodology to aquaculture samples made it possible to find several compounds from the target list, such as the antibiotic ciprofloxacin, the insecticide pirimiphos-methyl, and the mycotoxins fumonisin B2 and zearalenone. A retrospective analysis of accurate-mass full-spectrum acquisition data provided by QTOF MS was also made, without either reprocessing or injecting the samples. This allowed the detection and tentative identification of other organic undesirables different from those included in the validated list.

  11. Simulation of the Regional Ground-Water-Flow System and Ground-Water/Surface-Water Interaction in the Rock River Basin, Wisconsin

    Science.gov (United States)

    Juckem, Paul F.

    2009-01-01

    A regional, two-dimensional, areal ground-water-flow model was developed to simulate the ground-water-flow system and ground-water/surface-water interaction in the Rock River Basin. The model was developed by the U.S. Geological Survey (USGS), in cooperation with the Rock River Coalition. The objectives of the regional model were to improve understanding of the ground-water-flow system and to develop a tool suitable for evaluating the effects of potential regional water-management programs. The computer code GFLOW was used because of the ease with which the model can simulate ground-water/surface-water interactions, provide a framework for simulating regional ground-water-flow systems, and be refined in a stepwise fashion to incorporate new data and simulate ground-water-flow patterns at multiple scales. The ground-water-flow model described in this report simulates the major hydrogeologic features of the modeled area, including bedrock and surficial aquifers, ground-water/surface-water interactions, and ground-water withdrawals from high-capacity wells. The steady-state model treats the ground-water-flow system as a single layer with hydraulic conductivity and base elevation zones that reflect the distribution of lithologic groups above the Precambrian bedrock and a regionally significant confining unit, the Maquoketa Formation. In the eastern part of the Basin where the shale-rich Maquoketa Formation is present, deep ground-water flow in the sandstone aquifer below the Maquoketa Formation was not simulated directly, but flow into this aquifer was incorporated into the GFLOW model from previous work in southeastern Wisconsin. Recharge was constrained primarily by stream base-flow estimates and was applied uniformly within zones guided by regional infiltration estimates for soils. The model includes average ground-water withdrawals from 1997 to 2006 for municipal wells and from 1997 to 2005 for high-capacity irrigation, industrial, and commercial wells. In addition

  12. Surface Water Connectivity, Flow Pathways and Water Level Fluctuation in a Cold Region Deltaic Ecosystem

    Science.gov (United States)

    Peters, D. L.; Niemann, O.; Skelly, R.; Monk, W. A.; Baird, D. J.

    2017-12-01

    The Peace-Athabasca Delta (PAD) is a 6000 km2 deltaic floodplain ecosystem of international importance (Wood Buffalo National Park, Ramsar Convention, UNESCO World Heritage, and SWOT satellite water level calibration/validation site). The low-relief floodplain formed at the confluence of the Peace, Athabasca and Birch rivers with Lake Athabasca. More than 1000 wetland and lake basins have varying degrees of connectivity to the main flow system. Hydroperiod and water storage is influenced by ice-jam and open-water inundations and prevailing semi-arid climate that control water drawdown. Prior studies have identified pathways of river-to-wetland floodwater connection and historical water level fluctuation/trends as a key knowledge gaps, limiting our knowledge of deltaic ecosystem status and potential hydroecological responses to climate change and upstream water alterations to flow contributions. To address this knowledge gap, surface elevation mapping of the PAD has been conducted since 2012 using aerial remote sensing Light Detection and Ranging (LiDAR), plus thousands of ground based surface and bathymetric survey points tied to Global Positioning System (GPS) were obtained. The elevation information was used to develop a high resolution digital terrain model to simulate and investigate surface water connectivity. Importantly, the surveyed areas contain a set of wetland monitoring sites where ground-based surface water connectivity, water level/depth, water quality, and aquatic ecology (eg, vegetation, macroinvertebrate and muskrat) have been examined. The goal of this presentation is to present an assessment of: i) surface water fluctuation and connectivity for PAD wetland sites; ii) 40+ year inter-annual hydroperiod reconstruction for a perched basin using a combination of field measurements, remote sensing estimates, and historical documents; and iii) outline an approach to integrate newly available hydro-bio-geophysical information into a novel, multi

  13. Water flow and solute transport using environmental isotopes and modeling

    International Nuclear Information System (INIS)

    Hussein, M.F.

    2001-01-01

    The deep unsaturated zone may be a useful hydrological archive in desert environments characterized by scant or sporadic rainfall and slow percolation of rainwater over decades or even centuries. This moisture archive provides a useful way to distinguish the net downward flow of recharge water, whereas the isotopic composition and concentration of the conservative solutes of the preserved moisture could be used to reconstruct the history of recharge under the prevailing deficient water balance. The major advantage of such coupled approach is to obtain independent estimates of groundwater recharge rates which are normally difficult to evaluate using the hydrological methods applied in the temperate zones. The study was conducted in the Shiekh-Zoweid/Raffa area in the northeastern coastal strip of Sinai Peninsula. Bore-holes were dry-drilled in a line perpendicular to the sea shoreline (using an 8-inch diameter hand-operated rotary rig) for the unsaturated sediment collection from successive 0.5m thick layers down to a depth of 20m. Samples were investigated for the moisture contents and the chemical and isotope composition of this moisture was determined. Physical parameters were also assessed including porosity and volumetric moisture content. Chloride mass-balance was used to calculate recharge rates through the unsaturated zone by predicting the position of the 1963-Tritium peak in the unsaturated column. Analysis of moisture, chloride and deuterium profiles showed three principle peaks (along with minor ones) in Karafin site indicating few major recharge events that have taken place during the last few decades. Adjustment of these episodes has also been attempted using two historical major rainfall events (known from nearby meteorological stations). Application of the methodology in water resources management in arid regions is discussed. (author)

  14. A sea water barrier to coral gene flow.

    Science.gov (United States)

    Lessios, H A

    2012-11-01

    Land is not the only barrier to dispersal encountered by marine organisms. For sedentary shallow water species, there is an additional, marine barrier, 5000 km of uninterrupted deep-water stretch between the central and the eastern Pacific. This expanse of water, known as the ‘Eastern Pacific Barrier’, has been separating faunas of the two oceanic regions since the beginning of the Cenozoic. Species with larvae that cannot stay in the plankton for the time it takes to cross between the two sides have been evolving independently. That the eastern Pacific does not share species with the rest of the Pacific was obvious to naturalists two centuries ago (Darwin 1860). Yet, this rule has exceptions. A small minority of species are known to straddle the Eastern Pacific Barrier. One such exception is the scleractinian coral Porites lobata (Fig. 1). This species is spread widely throughout the Indo-Pacific, where it is one of the major reef-builders, but it is also encountered in the eastern Pacific. Are eastern and central Pacific populations of this coral connected by gene flow? In this issue of Molecular Ecology, Baums et al. (2012) use microsatellite data to answer this question. They show that P. lobata populations in the eastern Pacific are cut off from genetic influx from the rest of the Pacific. Populations within each of the two oceanic regions are genetically connected (though those in the Hawaiian islands are also isolated). Significantly, the population in the Clipperton Atoll, the westernmost island in the eastern Pacific, genetically groups with populations from the central Pacific, suggesting that crossing the Eastern Pacific Barrier by P. lobata propagules does occasionally occur.

  15. A study of water hammer phenomena in a one-component two-phase bubbly flow

    International Nuclear Information System (INIS)

    Fujii, Terushige; Akagawa, Koji

    2000-01-01

    Water hammer phenomena caused by a rapid valve closure, that is, shock phenomena in two-phase flows, are an important problem for the safety assessment of a hypothetical LOCA. This paper presents the results of experimental and analytical studies of the water hammer phenomena in a one-component tow-phase bubbly flow. In order to clarify the characteristics of water hammer phenomena, experiments for a one-component two-phase flow of Freon R-113 were conducted and a numerical simulation of pressure transients was developed. An overall picture of the water hammer phenomena in a one-component two-phase flow is presented an discussed. (author)

  16. 33 CFR 2.34 - Waters subject to tidal influence; waters subject to the ebb and flow of the tide; mean high water.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Waters subject to tidal influence; waters subject to the ebb and flow of the tide; mean high water. 2.34 Section 2.34 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY GENERAL JURISDICTION Jurisdictional Terms § 2...

  17. Undesired Behaviors Faced in Classroom by Physics Teachers in High Schools

    Science.gov (United States)

    Bayar, Adem; Kerns, James H.

    2015-01-01

    The aim of this study is to define undesired behaviors in the classroom, to better understand the reasons of these undesired behaviors, and to offer strategies to overcome these behaviors. The researchers have used a qualitative research approach in this study. For this aim, the researchers have purposefully selected 12 physics teachers who work…

  18. Simulation of water flows in multiple columns with small outlets

    International Nuclear Information System (INIS)

    Suh, Yong Kweon; Li, Zi Lu; Jeong, Jong Hyun; Lee, Jun Hee

    2006-01-01

    High-pressure die casting such as thixocasting and rheocasting is an effective process in the manufacturing automotive parts. Following the recent trend in the automotive manufacturing technologies, the product design subject to the die casting becomes more and more complex. Simultaneously the injection speed is also designed to be very high to establish a short cycle-time. Thus, the requirement of the die design becomes more demanding than ever before. In some cases the product's shape can have multiple slender manifolds. In such cases, design of the inlet and outlet parts of the die is very important in the whole manufacturing process. The main issues required for the qualified products are to attain gentle and uniform flow of the molten liquid within the passages of the die. To satisfy such issues, the inlet cylinder ('bed cylinder' in this paper) must be as large as possible and simultaneously the outlet opening at the end of each passage must be as small as possible. However these in turn obviously bring additional manufacturing costs caused by re-melting of the bed cylinder and increased power due to the small outlet-openings. The purpose of this paper is to develop effective simulation methods of calculation for fluid flows in multiple columns, which mimic the actual complex design, and to get some useful information which can give some contributions to the die-casting industry. We have used a commercial code CFX in the numerical simulation. The primary parameter involved is the size of the bed cylinder. We will show how the very small opening of the outlet can be treated with the aid of the porous model provided in the code. To check the validity of the numerical results we have also conducted a simple experiment by using water

  19. Multivariate recurrence network analysis for characterizing horizontal oil-water two-phase flow.

    Science.gov (United States)

    Gao, Zhong-Ke; Zhang, Xin-Wang; Jin, Ning-De; Marwan, Norbert; Kurths, Jürgen

    2013-09-01

    Characterizing complex patterns arising from horizontal oil-water two-phase flows is a contemporary and challenging problem of paramount importance. We design a new multisector conductance sensor and systematically carry out horizontal oil-water two-phase flow experiments for measuring multivariate signals of different flow patterns. We then infer multivariate recurrence networks from these experimental data and investigate local cross-network properties for each constructed network. Our results demonstrate that a cross-clustering coefficient from a multivariate recurrence network is very sensitive to transitions among different flow patterns and recovers quantitative insights into the flow behavior underlying horizontal oil-water flows. These properties render multivariate recurrence networks particularly powerful for investigating a horizontal oil-water two-phase flow system and its complex interacting components from a network perspective.

  20. Experimental study on effects of double pumps switching on water supply flow rate

    International Nuclear Information System (INIS)

    Wang Xin; Han Weishi

    2012-01-01

    Flow characteristics in the process of switching one centrifugal pump to the other was investigated experimentally using a closed loop with two centrifugal pumps and two check valves. Characteristics of the check valves responding and the flow rate changing during the process of switching was studied by experimental data analysis. The results show that in the switching process with high and low original flow rate, the restoring time is 26 s and 21 s respectively; the lowest flow rates are 59.4% and 87.2% out of that in normal water supply, and the average deficit of feed water is 20.8% and 7.5% respectively. Compared to double-pump switching with low flow rate, a longer transition time. more intense flow fluctuations and increased water loss are observed with high flow rate, which has significantly effects on the stability of water supply. (authors)

  1. Gas and water flow in the Callovo-Oxfordian argillite

    International Nuclear Information System (INIS)

    Harrington, J.F.; Noy, D.J.; Talandier, J.

    2010-01-01

    Document available in extended abstract form only. Understanding the impact and fate of this gas phase is of significant importance within performance assessment and for the accurate long-term prediction of repository evolution. This paper describes the initial results from an ongoing experimental study to measure the two-phase flow behaviour of the Callovo-Oxfordian argillite from the Bure underground research laboratory (URL) in France, using the custom-designed BGS permeameter. The primary objectives of the study are to measure: (i) the hydraulic conductivity and intrinsic permeability; (ii) the capillary displacement pressure; (iii) the effective gas permeability and relative permeability to gas for a range of conditions; and (iv) the post-test gas saturation. During testing, the specimen, a cylinder of 54 mm thickness, cut perpendicular to bedding, is subject to an isotropic confining stress, with fluids injected through the base of the specimen. A novel feature of the apparatus is the use of porous annular guard-ring filters around the inflow and outflow filters. The pressures in these two 'guard-rings' can be independently monitored to provide data on the distribution of pressure and anisotropy of the sample. Initial measurements, performed on a specimen orientation perpendicular to the bedding plane, have been divided into three components: re-saturation and consolidation; hydraulic properties; gas behaviour. During the initial period of equilibration, re-saturation of the sample were noted. Net volume change due to re-saturation closely agreed with pre-test geotechnical measurements of water saturation, suggesting the bulk of the gas phase was resident in non-dilatant pores and that the specimen was fully saturated at the onset of testing. A two step consolidation test was then performed with confining pressure raised to 11 MPa for 5 days and then to 12.5 MPa for a further 8 days. Values for drained bulk modulus based on the total volume of fluid

  2. Construction of estimated flow- and load-duration curves for Kentucky using the Water Availability Tool for Environmental Resources (WATER)

    Science.gov (United States)

    Unthank, Michael D.; Newson, Jeremy K.; Williamson, Tanja N.; Nelson, Hugh L.

    2012-01-01

    Flow- and load-duration curves were constructed from the model outputs of the U.S. Geological Survey's Water Availability Tool for Environmental Resources (WATER) application for streams in Kentucky. The WATER application was designed to access multiple geospatial datasets to generate more than 60 years of statistically based streamflow data for Kentucky. The WATER application enables a user to graphically select a site on a stream and generate an estimated hydrograph and flow-duration curve for the watershed upstream of that point. The flow-duration curves are constructed by calculating the exceedance probability of the modeled daily streamflows. User-defined water-quality criteria and (or) sampling results can be loaded into the WATER application to construct load-duration curves that are based on the modeled streamflow results. Estimates of flow and streamflow statistics were derived from TOPographically Based Hydrological MODEL (TOPMODEL) simulations in the WATER application. A modified TOPMODEL code, SDP-TOPMODEL (Sinkhole Drainage Process-TOPMODEL) was used to simulate daily mean discharges over the period of record for 5 karst and 5 non-karst watersheds in Kentucky in order to verify the calibrated model. A statistical evaluation of the model's verification simulations show that calibration criteria, established by previous WATER application reports, were met thus insuring the model's ability to provide acceptably accurate estimates of discharge at gaged and ungaged sites throughout Kentucky. Flow-duration curves are constructed in the WATER application by calculating the exceedence probability of the modeled daily flow values. The flow-duration intervals are expressed as a percentage, with zero corresponding to the highest stream discharge in the streamflow record. Load-duration curves are constructed by applying the loading equation (Load = Flow*Water-quality criterion) at each flow interval.

  3. A multiphase flow meter for the on-line determination of the flow rates of oil, water and gas

    International Nuclear Information System (INIS)

    Roach, G.J.; Watt, J.S.

    1997-01-01

    Multiphase mixtures of crude oil, formation water and gas are carried in pipelines from oil wells to production facilities. Multiphase flow meters (MFMs) are being developed to determine the flow rates of each component of the heterogeneous mixture in the pipeline. CSIRO Minerals has developed and field tested a gamma-ray MFM for the on-line determination of the flow rates of heterogeneous mixtures of oil, water and gas in pipelines. It consists of two specialised gamma-ray transmission gauges, and pressure and temperature sensors, mounted on the pipeline carrying the full flow of the production stream. The MFM separately measures liquids and gas flow rates, and the volume ratio of water and liquids (water cut). The MFM has been trialled at three offshore production facilities in Australia. In each, the MFM was mounted on the pipeline between the test manifold and the test separator. The multiphase streams from the various wells feeding to the platform were sequentially routed past the MFM. The MFM and test separator outputs were compared using regression analysis. The flow rates of oil, water and gas were each determined to relative errors in the range of 5-10% . The MFM has been in routine use on the West Kingfish platform in the Bass Strait since November 1994. The MFM was recently tested over a wide range of flow conditions at a Texaco flow facility near Houston. Water cut, based on pre-trial calibration, was determined to 2% rms over the range 0-100% water cut. The liquids and gas flow results were interpreted based on slip correlations obtained from comparison of the MFM and Texaco flows. Using these, the relative errors were respectively 6.6% for liquid flow, 6.2% for gas, 8% for oil and 8% for water. The MFM is licensed to Kvaerner FSSL of Aberdeen. Kvaerner will supply the gamma-ray MFM for both platform and subsea use. Technology transfer commenced in December 1996, and Kvaerner completed the manufacture of the first MFM in August 1997

  4. Effect of Water Cut on Pressure Drop of Oil (D130) -Water Flow in 4″Horizontal Pipe

    Science.gov (United States)

    Basha, Mehaboob; Shaahid, S. M.; Al-Hems, Luai M.

    2018-03-01

    The oil-water flow in pipes is a challenging subject that is rich in physics and practical applications. It is often encountered in many oil and chemical industries. The pressure gradient of two phase flow is still subject of immense research. The present study reports pressure measurements of oil (D130)-water flow in a horizontal 4″ diameter stainless steel pipe at different flow conditions. Experiments were carried out for different water cuts (WC); 0-100%. Inlet oil-water flow rates were varied from 4000 to 8000 barrels-per-day in steps of 2000. It has been found that the frictional pressure drop decreases for WC = 0 - 40 %. With further increase in WC, friction pressure drop increases, this could be due to phase inversion.

  5. Managing Water Sustainability: Virtual Water Flows and Economic Water Productivity Assessment of the Wine Trade between Italy and the Balkans

    Directory of Open Access Journals (Sweden)

    Pier Paolo Miglietta

    2018-02-01

    Full Text Available The management of natural resources in economic activities has become a fundamental issue when considering the perspective of sustainable development. It is necessary to rethink every process in order to reach efficiency from different points of view, not only environmentally but also economically. Water scarcity is growing because of economic and population growth, climate change, and the increasing water demand. Currently, agri-food represents the most water consumptive sector, and the increasing importance of international trade in this industry puts freshwater issues in a global context that should be analyzed and regulated by sustainable policies. This analysis is focused on virtual water flows and economic water productivity related to the wine trade, and aims to evaluate water loss/savings achieved through bilateral trade relations. The choice fell on Italy, the first wine producer in the world, and the Balkan countries. The latter are new markets for wine production/consumption, in which Italian wines are strongly positioned for different reasons. The results show that, from a national point of view and considering wine trade, Italy exports water in virtual form to the Balkan countries, more than it imports, so that in effect it partially uses its own water resources for the wine supply of the Balkans. The latter, on the other hand, being a net importer of wine, partially depends on Italian water resources and exerts less pressure on their own water basins in the supporting wine supply. We also observed that the wine trade between Italy and the Balkans implies global water savings.

  6. Formation of undesired by-products in deNO{sub x} catalysis by hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Radtke, Frank; Koeppel, Rene A; Baiker, Alfons [Department of Chemical Engineering and Industrial Chemistry, Swiss Federal Institute of Technology, ETH-Zentrum, Zuerich (Switzerland)

    1995-11-20

    The catalytic performance of Cu/ZSM-5 and {gamma}-alumina in the selective catalytic reduction of nitrogen oxides by alkenes in excess oxygen and the formation of potentially harmful by-products such as hydrogen cyanide, cyanic acid, ammonia, nitrous oxide and carbon monoxide have been studied by means of FT-IR-gas phase analysis. Over Cu/ZSM-5 the reduction activity was strongly influenced by the type of hydrocarbon, while there was no significant difference when starting from NO or NO{sub 2}. In contrast, with {gamma}-alumina NO{sub 2} was reduced more efficiently than NO with both reductants. Water addition strongly suppressed the catalytic activity of {gamma}-alumina. Regarding the formation of undesired by-products, substantial amounts of carbon monoxide were observed in all experiments, independently of the feed composition. The type of catalyst, the use of either NO or NO{sub 2}, the alkene used as a reductant and water strongly influenced the formation of other by-products. With alumina ethene showed a lower tendency to form HCN as compared to propene and water addition further suppressed by-product formation. This contrasts the findings with Cu/ZSM-5, where HCN production was not significantly altered by the presence of water. On this catalyst HNCO was found additionally for dry feeds, whereas ammonia appeared in the presence of water in the same temperature range. Under special feed gas compositions further by-products, formaldehyde and hydrocarbons, were found over Cu/ZSM-5, whereas none of these compounds were observed over {gamma}-alumina

  7. Assessing microbiological water quality in drinking water distribution systems with disinfectant residual using flow cytometry.

    Science.gov (United States)

    Gillespie, Simon; Lipphaus, Patrick; Green, James; Parsons, Simon; Weir, Paul; Juskowiak, Kes; Jefferson, Bruce; Jarvis, Peter; Nocker, Andreas

    2014-11-15

    Flow cytometry (FCM) as a diagnostic tool for enumeration and characterization of microorganisms is rapidly gaining popularity and is increasingly applied in the water industry. In this study we applied the method to obtain a better understanding of total and intact cell concentrations in three different drinking water distribution systems (one using chlorine and two using chloramines as secondary disinfectants). Chloramine tended to result in lower proportions of intact cells than chlorine over a wider residual range, in agreement with existing knowledge that chloramine suppresses regrowth more efficiently. For chlorinated systems, free chlorine concentrations above 0.5 mg L(-1) were found to be associated with relatively low proportions of intact cells, whereas lower disinfectant levels could result in substantially higher percentages of intact cells. The threshold for chlorinated systems is in good agreement with guidelines from the World Health Organization. The fact that the vast majority of samples failing the regulatory coliform standard also showed elevated proportions of intact cells suggests that this parameter might be useful for evaluating risk of failure. Another interesting parameter for judging the microbiological status of water, the biological regrowth potential, greatly varied among different finished waters providing potential help for investment decisions. For its measurement, a simple method was introduced that can easily be performed by water utilities with FCM capability. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Study of gas-water flow in horizontal rectangular channels

    Science.gov (United States)

    Chinnov, E. A.; Ron'shin, F. V.; Kabov, O. A.

    2015-09-01

    The two-phase flow in the narrow short horizontal rectangular channels 1 millimeter in height was studied experimentally. The features of formation of the two-phase flow were studied in detail. It is shown that with an increase in the channel width, the region of the churn and bubble regimes increases, compressing the area of the jet flow. The areas of the annular and stratified flow patterns vary insignificantly.

  9. Virtual water flows related to land use in an intensive agriculture in the Fergana Valley, Uzbekistan

    Science.gov (United States)

    Klipstein, A.; Schneider, K.; Breuer, L.; Frede, H. G.

    2009-04-01

    Due to low annual precipitation, agricultural production in Uzbekistan is depending on irrigation from the Syrdarya and Amudarya rivers to a great deal. One of the most important cash crops of the country is cotton. Current irrigation management leads to elevated groundwater levels, salinization of soils and to a degradation of soil and water resources. Through export of cotton and other crops, the problems related to water consumption and water management are transported beyond the producing country. The amount of water transported through production and export is referred to as virtual water. To distinguish between productive and unproductive partitioning of water flows, the terms green and blue water have been introduced. Information on virtual water flows due to crop production usually only exist on country level. To reduce uncertainties related to generalization, the effect of land management and environmental factors on the partitioning of water flows needs to be studied on smaller scales. The presented study analyzes water fluxes in an intensively used agricultural area in the Fergana Valley, Uzbekistan. The study aims to a) quantify crop specific water consumption in agricultural production under current management and b) analyze water use efficiency as subject to land use and irrigation management. Based on crop production, irrigation management and environmental conditions in the study area, virtual water flows will be calculated on the level of agricultural collectives (Water Users Associations). In a further step, the partitioning of green and blue water fluxes will be quantified. Alternative scenarios for improved water management will be analyzed in a model study.

  10. FlowIDS

    OpenAIRE

    Sabolčák, Peter

    2006-01-01

    FlowIDS is system which can detect some of the undesirable traffi c in computer networks (undesirable traffic could be also ie. virus activity or overloading of network) and mostly doing counteraction which are set by administrator. Information about data ows are provided by hardware of network infrastructure, eliminitaion of undesirable activity is done through changes in network hardware settings. Regarding the quantity of solution which are provided on market, I decided to focus on Cisco n...

  11. Estimating drain flow from measured water table depth in layered soils under free and controlled drainage

    Science.gov (United States)

    Saadat, Samaneh; Bowling, Laura; Frankenberger, Jane; Kladivko, Eileen

    2018-01-01

    Long records of continuous drain flow are important for quantifying annual and seasonal changes in the subsurface drainage flow from drained agricultural land. Missing data due to equipment malfunction and other challenges have limited conclusions that can be made about annual flow and thus nutrient loads from field studies, including assessments of the effect of controlled drainage. Water table depth data may be available during gaps in flow data, providing a basis for filling missing drain flow data; therefore, the overall goal of this study was to examine the potential to estimate drain flow using water table observations. The objectives were to evaluate how the shape of the relationship between drain flow and water table height above drain varies depending on the soil hydraulic conductivity profile, to quantify how well the Hooghoudt equation represented the water table-drain flow relationship in five years of measured data at the Davis Purdue Agricultural Center (DPAC), and to determine the impact of controlled drainage on drain flow using the filled dataset. The shape of the drain flow-water table height relationship was found to depend on the selected hydraulic conductivity profile. Estimated drain flow using the Hooghoudt equation with measured water table height for both free draining and controlled periods compared well to observed flow with Nash-Sutcliffe Efficiency values above 0.7 and 0.8 for calibration and validation periods, respectively. Using this method, together with linear regression for the remaining gaps, a long-term drain flow record for a controlled drainage experiment at the DPAC was used to evaluate the impacts of controlled drainage on drain flow. In the controlled drainage sites, annual flow was 14-49% lower than free drainage.

  12. Past, current and future water footprints, water scarcity and virtual water flows in China

    NARCIS (Netherlands)

    Zhuo, L.

    2016-01-01

    The increasing water consumption as a result of population growth and economic development, especially in fast growing developing countries, puts an increasing strain on the sustainable use of the globe’s finite freshwater resources and poses a key challenge for the future. The objective of the

  13. Modification of light utilization for skeletal growth by water flow in the scleractinian coral Galaxea fascicularis

    NARCIS (Netherlands)

    Schutter, M.; Kranenbarg, S.; Wijffels, R.H.; Verreth, J.A.J.; Osinga, R.

    2011-01-01

    In this study, we tested the hypothesis that the importance of water flow for skeletal growth (rate) becomes higher with increasing irradiance levels (i.e. a synergistic effect) and that such effect is mediated by a water flow modulated effect on net photosynthesis. Four series of nine nubbins of G.

  14. Griswold Tempered Water Flow Regulator Valves Used as Anti-Siphon Valves

    International Nuclear Information System (INIS)

    MISKA, C.

    2000-01-01

    FCV-1*22 and 1*23 are Griswold constant flow regulators used as anti-siphon valves in the tempered water system, they fail closed but valve cartridge orifice allows minimum flow to prevent loss of water from the MCO/CASK annulus

  15. within plant resistance to water flow in tomato and sweet melons

    African Journals Online (AJOL)

    Administrator

    high pressure flow meter (HPFM) and evaporative flux (EF) methods. In the evaporative flux method, measure- ments of transpiration flux and leaf water potential were used to calculate the total resistance to water flow using. Ohm's law analogy. Measurements of tranpiration flux (Q) relationship, plant resistance calculated ...

  16. Basal interstitial water pressure in laboratory debris flows over a rigid bed in an open channel

    Directory of Open Access Journals (Sweden)

    N. Hotta

    2012-08-01

    Full Text Available Measuring the interstitial water pressure of debris flows under various conditions gives essential information on the flow stress structure. This study measured the basal interstitial water pressure during debris flow routing experiments in a laboratory flume. Because a sensitive pressure gauge is required to measure the interstitial water pressure in shallow laboratory debris flows, a differential gas pressure gauge with an attached diaphragm was used. Although this system required calibration before and after each experiment, it showed a linear behavior and a sufficiently high temporal resolution for measuring the interstitial water pressure of debris flows. The values of the interstitial water pressure were low. However, an excess of pressure beyond the hydrostatic pressure was observed with increasing sediment particle size. The measured excess pressure corresponded to the theoretical excess interstitial water pressure, derived as a Reynolds stress in the interstitial water of boulder debris flows. Turbulence was thought to induce a strong shear in the interstitial space of sediment particles. The interstitial water pressure in boulder debris flows should be affected by the fine sediment concentration and the phase transition from laminar to turbulent debris flow; this should be the subject of future studies.

  17. ENVIRONMENTAL RESEARCH BRIEF : ANALYTIC ELEMENT MODELING OF GROUND-WATER FLOW AND HIGH PERFORMANCE COMPUTING

    Science.gov (United States)

    Several advances in the analytic element method have been made to enhance its performance and facilitate three-dimensional ground-water flow modeling in a regional aquifer setting. First, a new public domain modular code (ModAEM) has been developed for modeling ground-water flow ...

  18. Recurrence network analysis of experimental signals from bubbly oil-in-water flows

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Zhong-Ke; Zhang, Xin-Wang; Du, Meng [School of Electrical Engineering and Automation, Tianjin University, Tianjin 300072 (China); Jin, Ning-De, E-mail: ndjin@tju.edu.cn [School of Electrical Engineering and Automation, Tianjin University, Tianjin 300072 (China)

    2013-02-04

    Based on the signals from oil–water two-phase flow experiment, we construct and analyze recurrence networks to characterize the dynamic behavior of different flow patterns. We first take a chaotic time series as an example to demonstrate that the local property of recurrence network allows characterizing chaotic dynamics. Then we construct recurrence networks for different oil-in-water flow patterns and investigate the local property of each constructed network, respectively. The results indicate that the local topological statistic of recurrence network is very sensitive to the transitions of flow patterns and allows uncovering the dynamic flow behavior associated with chaotic unstable periodic orbits.

  19. Recurrence network analysis of experimental signals from bubbly oil-in-water flows

    International Nuclear Information System (INIS)

    Gao, Zhong-Ke; Zhang, Xin-Wang; Du, Meng; Jin, Ning-De

    2013-01-01

    Based on the signals from oil–water two-phase flow experiment, we construct and analyze recurrence networks to characterize the dynamic behavior of different flow patterns. We first take a chaotic time series as an example to demonstrate that the local property of recurrence network allows characterizing chaotic dynamics. Then we construct recurrence networks for different oil-in-water flow patterns and investigate the local property of each constructed network, respectively. The results indicate that the local topological statistic of recurrence network is very sensitive to the transitions of flow patterns and allows uncovering the dynamic flow behavior associated with chaotic unstable periodic orbits.

  20. Air-water two-phase flow through a pipe junction

    International Nuclear Information System (INIS)

    Suu, Tetsuo

    1991-01-01

    The distribution of the local void fraction across the section of the conduit was studied experimentally in air-water two-phase flow flowing through a pipe junction with the branching angle of 90deg and the area ratio of unity. As in the previous report, the main conduit of the junction was set up vertically and upward air-water bubbly and slug flows were arranged in the main upstream section. If the flow regime, the quality and the ratio of lateral mass flow discharge of water to total mass flow discharge of water are the same, the larger the Reynolds number is, the more violent the variety of the local void fraction distribution adjacent to the branching part in the lateral conduit is. However, the variety in the main downstream section is scarcely influenced by the Reynolds number. (author)

  1. Investigation results on water quality and volume of flowing-in water to the Yotsugi slag heap site. 2

    International Nuclear Information System (INIS)

    Naganuma, Masaki; Taki, Tomihiro; Takimoto, Sadao; Makita, A.

    2000-05-01

    Mining water flowing into the Yotsugi slag heap site at the Ningyo-toge Environment Technical Center is exhausted to a common river after carrying out the treatment of uranium and radium in the mining water at the previously settled mining water treatment facility and confirming it to be less than management target value on the river water within the site boundary regulated by the agreement on environmental conservation with Okayama prefecture and Kami-saihara mura. In order to elucidate some required treatment on every water system flowing-in the heap site as a part of reduction of flowing volume on taking action of the heap site, an investigation on its water quality and volume was carried out. As a result, it was confirmed on water quality that uranium values of every river were all less than their target values but radium values of them were all over their target values which necessitated conventional water treatment. And, on water volume, it was confirmed that flowing water volume from the exposed excavation site was reduced about 40% in comparison with same rain-fall before removing from rain water. (G.K.)

  2. Hardware Development of Ultrasonic Tomography for Composition Determination of Water and Oil Flow

    Directory of Open Access Journals (Sweden)

    Ruzairi Abdul Rahim

    2007-01-01

    Full Text Available A monitoring system for water and oil flow using ultrasonic Tomography is implemented. Information such as the type of flow, the composition of the water and oil can be obtained from the system. The composition of the flow is determined based on the propagation time of the ultrasonic waves. The ultrasonic Tomography system includes the sensors fixture design, signal conditioning circuits and image reconstruction software. The image reconstruction algorithm that used is the Linear Back Projection (LBP algorithm.

  3. Scaling-Laws of Flow Entropy with Topological Metrics of Water Distribution Networks

    OpenAIRE

    Giovanni Francesco Santonastaso; Armando Di Nardo; Michele Di Natale; Carlo Giudicianni; Roberto Greco

    2018-01-01

    Robustness of water distribution networks is related to their connectivity and topological structure, which also affect their reliability. Flow entropy, based on Shannon’s informational entropy, has been proposed as a measure of network redundancy and adopted as a proxy of reliability in optimal network design procedures. In this paper, the scaling properties of flow entropy of water distribution networks with their size and other topological metrics are studied. To such aim, flow entropy, ma...

  4. Water cut measurement of oil–water flow in vertical well by combining total flow rate and the response of a conductance probe

    International Nuclear Information System (INIS)

    Chen, Jianjun; Xu, Lijun; Cao, Zhang; Zhang, Wen; Liu, Xingbin; Hu, Jinhai

    2015-01-01

    In this paper, a conductance probe-based well logging instrument was developed and the total flow rate is combined with the response of the conductance probe to estimate the water cut of the oil–water flow in a vertical well. The conductance probe records the time-varying electrical characteristics of the oil–water flow. Linear least squares regression (LSR) and nonlinear support vector regression (SVR) were used to establish models to map the total flow rate and features extracted from the probe response onto the water cut, respectively. Principal component analysis (PCA) and partial least squares analysis (PLSA) techniques were employed to reduce data redundancy within the extracted features. An experiment was carried out in a vertical pipe with an inner diameter of 125 mm and a height of 24 m in an experimental multi-phase flow setup, Daqing Oilfield, China. In the experiment, oil–water flow was used and the total flow rate varied from 10 to 200 m 3 per day and the water cut varied from 0% to 100%. As a direct comparison, the cases were also studied when the total flow rate was not used as an independent input to the models. The results obtained demonstrate that: (1) the addition of the total flow rate as an input to the regression models can greatly improve the accuracy of water cut prediction, (2) the nonlinear SVR model performs much better than the linear LSR model, and (3) for the SVR model with the total flow rate as an input, the adoption of PCA or PLSA not only decreases the dimensions of inputs, but also increases prediction accuracy. The SVR model with five PCA-treated features plus the total flow rate achieves the best performance in water cut prediction, with a coefficient of determination (R 2 ) as high as 0.9970. The corresponding root mean squared error (RMSE) and mean quoted error (MQE) are 0.0312% and 1.99%, respectively. (paper)

  5. Experimental on two sensors combination used in horizontal pipe gas-water two-phase flow

    International Nuclear Information System (INIS)

    Wu, Hao; Dong, Feng

    2014-01-01

    Gas-water two phase flow phenomenon widely exists in production and living and the measurement of it is meaningful. A new type of long-waist cone flow sensor has been designed to measure two-phase mass flow rate. Six rings structure of conductance probe is used to measure volume fraction and axial velocity. The calibration of them have been made. Two sensors have been combined in horizontal pipeline experiment to measure two-phase flow mass flow rate. Several model of gas-water two-phase flow has been discussed. The calculation errors of total mass flow rate measurement is less than 5% based on the revised homogeneous flow model

  6. Flow in water-intake pump bays: A guide for utility engineers. Final report

    International Nuclear Information System (INIS)

    Ettema, R.

    1998-09-01

    This report is intended to serve as a guide for power-plant engineers facing problems with flow conditions in pump bays in water-intake structures, especially those located alongside rivers. The guide briefly introduces the typical prevailing flow field outside of a riverside water intake. That flow field often sets the inflow conditions for pump bays located within the water intake. The monograph then presents and discusses the main flow problems associated with pump bays. The problems usually revolve around the formation of troublesome vortices. A novel feature of this monograph is the use of numerical modeling to reveal diagnostically how the vortices form and their sensitivities to flow conditions, such as uniformity of approach flow entering the bay and water-surface elevation relative to pump-bell submergence. The modeling was carried out using a computer code developed specially for the present project. Pump-bay layouts are discussed next. The discussion begins with a summary of the main variables influencing bay flows. The numerical model is used to determine the sensitivities of the vortices to variations in the geometric parameters. The fixes include the use of flow-control vanes and suction scoops for ensuring satisfactory flow performance in severe flow conditions; notably flows with strong cross flow and shallow flows. The monograph ends with descriptions of modeling techniques. An extensive discussion is provided on the use of numerical model for illuminating bay flows. The model is used to show how fluid viscosity affects bay flow. The effect of fluid viscosity is an important consideration in hydraulic modeling of water intakes

  7. Complex network analysis in inclined oil–water two-phase flow

    International Nuclear Information System (INIS)

    Zhong-Ke, Gao; Ning-De, Jin

    2009-01-01

    Complex networks have established themselves in recent years as being particularly suitable and flexible for representing and modelling many complex natural and artificial systems. Oil–water two-phase flow is one of the most complex systems. In this paper, we use complex networks to study the inclined oil–water two-phase flow. Two different complex network construction methods are proposed to build two types of networks, i.e. the flow pattern complex network (FPCN) and fluid dynamic complex network (FDCN). Through detecting the community structure of FPCN by the community-detection algorithm based on K-means clustering, useful and interesting results are found which can be used for identifying three inclined oil–water flow patterns. To investigate the dynamic characteristics of the inclined oil–water two-phase flow, we construct 48 FDCNs under different flow conditions, and find that the power-law exponent and the network information entropy, which are sensitive to the flow pattern transition, can both characterize the nonlinear dynamics of the inclined oil–water two-phase flow. In this paper, from a new perspective, we not only introduce a complex network theory into the study of the oil–water two-phase flow but also indicate that the complex network may be a powerful tool for exploring nonlinear time series in practice. (general)

  8. Characteristics of soil under variations in clay, water saturation, and water flow rates, and the implications upon soil remediation

    International Nuclear Information System (INIS)

    Aikman, M.; Mirotchnik, K.; Kantzas, A.

    1997-01-01

    A potential remediation method for hydrocarbon contaminated soils was discussed. The new method was based on the use of proven and economic petroleum reservoir engineering methods for soil remediation. The methods that were applied included water and gas displacement methods together with horizontal boreholes as the flow inlet and outlets. This system could be used in the case of spills that seep beneath a plant or other immovable infrastructure which requires in-situ treatment schemes to decontaminate the soil. A study was conducted to characterize native soils and water samples from industrial plants in central Alberta and Sarnia, Ontario and to determine the variables that impact upon the flow conditions of synthetic test materials. The methods used to characterize the soils included X-Ray computed tomographic analysis, grain size and density measurements, and X-Ray diffraction. Clay content, initial water saturation, and water and gas flow rate were the variables that impacted on the flow conditions

  9. Water Management for Competing Uses: Environmental Flows in the Transboundary Rio Grande/Rio Bravo

    Science.gov (United States)

    Sandoval Solis, S.; McKinney, D. C.

    2011-12-01

    Introduction Due to high water demand, the scarcity of water, and the complexity of water allocation, environmental flows have not been considered as an integral part of the water management in the Rio Grande/Rio Bravo transboundary basin. The Big Bend reach is located between the cities of Presidio/Ojinaga to Amistad international reservoir, along the main stream (Fig. 1). Important environmental habitats such as the Big Bend National and State Park in the U.S., the Maderas del Carmen, Cañon de Santa Elena and Ocampo natural reserved areas in Mexico are ecologically threatened because of the lack of environmental water management policies. Several efforts have been undertaken by scientists, government agencies and NGOs to determine the environmental flows for this reach and water management policies that can provide these flows. Objective The objective of this research is to describe a water management policy that can conciliate environmental and human water uses in the Big Bend region. In other words, define a policy that can provide environmental flows without harming water supply for stakeholders or increasing flood risk, within legal and physical constraints of the system. Methodology First, the system was characterized identifying water users, hydraulic infrastructure, and water allocation according to state, federal and international regulations. Second, a hydrograph for environmental flows was proposed that mimics the hydrologic characteristics of the prior dam alteration. Third, a water planning model was constructed to evaluate alternative policies. Fourth, the water management is proposed to provide environmental restoration flows from Luis L. Leon reservoir. This policy considers mechanisms that reduce flooding and drought risks, while meting national and international water regulations. Results Three types of natural flow regimes are considered: (1) median flows aimed to provide the base flow in the region, (2) high flows to provide transversal

  10. Diverting the flow : gender equity and water in South Asia

    NARCIS (Netherlands)

    Zwarteveen, M.Z.; Ahmed, S.; Gautam, S.R.

    2012-01-01

    Across the South Asian region, water determines livelihoods and in some cases even survival. However, water also creates exclusions. Access to water, and its social organization, are intimately tied up with power relations. This book provides an overview of gender, equity and water issues relevant

  11. Early Regimes of Water Capillary Flow in Slit Silica Nanochannels

    DEFF Research Database (Denmark)

    Oyarzua, Elton; Walther, Jens Honore; Mejia, Andres

    2015-01-01

    on the dynamics of capillaryfilling. The results indicate that the nanoscale imbibition process is divided into three main flow regimes:an initial regime where the capillary force is balanced only by the inertial drag and characterized by aconstant velocity and a plug flow profile. In this regime, the meniscus...... velocity profiles identify the passage froman inviscid flow to a developing Poiseuille flow. Gas density profiles ahead of the capillary front indicatea transient accumulation of air on the advancing meniscus. Furthermore, slower capillary filling ratescomputed for higher air pressures reveal a significant...... retarding effect of the gas displaced by the advancing meniscus....

  12. Measurement of water flow rate in unsaturated soil by thermistor type sensor

    International Nuclear Information System (INIS)

    Takebe, Shinichi; Yamamoto, Tadatoshi; Wadachi, Yoshiki

    1981-09-01

    As a part of radiological safety studies for ground disposal of radioactive wastes, a measuring apparatus of water flow rate with thermistor type sensor was made as preliminary one and the measurement of water flow rate in the soil was carried out, in order to evalute by comparison of the migration rate of water with that of radionuclide in an unsaturated soil. The water flow rate can be determined by measuring the change of the thermal conductivity (temperature) of soil around the several thermistor type sensors set in a soil. Particularly at the region of low water content in the soil, the water flow rate was able to measure successfully by this apparatus. (author)

  13. Visual study of air--water mixtures flowing inside serpentine tubes

    International Nuclear Information System (INIS)

    Farukhi, M.N.; Parker, J.D.

    1974-01-01

    Hydrodynamic behavior of air-water mixtures flowing inside serpentine tubes, with bends in the vertical plane, was investigated. Flow visualization was accomplished by injecting dye into the liquid phase and recording the events on color slides and color movies. For certain combinations of gas and liquid flow rates, in the annular type flow regime, ''film inversion'' was observed in the bend as well as in the straight section immediately downstream of the bend. A new flow regime map particularly applicable to two phase flow inside serpentine tubes is presented. (U.S.)

  14. Magnetic Heat Pump Containing Flow Diverters

    Science.gov (United States)

    Howard, Frank S.

    1995-01-01

    Proposed magnetic heat pump contains flow diverters for suppression of undesired flows. If left unchecked, undesired flows mix substantial amounts of partially heated and partially cooled portions of working fluid, effectively causing leakage of heat from heated side to cooled side. By reducing leakage of heat, flow diverters increase energy efficiency of magnetic heat pump, potentially offering efficiency greater than compressor-driven refrigerator.

  15. A simple high efficiency solar water purification system

    Energy Technology Data Exchange (ETDEWEB)

    Duff, W.S.; Hodgson, D.A. [Colorado State University, Fort Collins, CO (United States). Dept. of Mechanical Engineering

    2005-07-01

    A new passive solar water pasteurization system based on density difference flow principles has been designed, built and tested. The system contains no valves and regulates flow based on the density difference between two columns of water. The new system eliminates boiling problems encountered in previous designs. Boiling is undesirable because it may contaminate treated water. The system with a total absorber area of 0.45 m2 has achieved a peak flow rate of 19.3 kg/h of treated water. Experiments with the prototype systems presented in this paper show that density driven systems are an attractive option to existing solar water pasteurization approaches. (author)

  16. Change regularity of water quality parameters in leakage flow conditions and their relationship with iron release.

    Science.gov (United States)

    Liu, Jingqing; Shentu, Huabin; Chen, Huanyu; Ye, Ping; Xu, Bing; Zhang, Yifu; Bastani, Hamid; Peng, Hongxi; Chen, Lei; Zhang, Tuqiao

    2017-11-01

    The long-term stagnation in metal water supply pipes, usually caused by intermittent consumption patterns, will cause significant iron release and water quality deterioration, especially at the terminus of pipelines. Another common phenomenon at the terminus of pipelines is leakage, which is considered helpful by allowing seepage of low-quality drinking water resulting from long-term stagnation. In this study, the effect of laminar flow on alleviating water quality deterioration under different leakage conditions was investigated, and the potential thresholds of the flow rate, which can affect the iron release process, were discussed. Based on a galvanized pipe and ductile cast iron pipe pilot platform, which was established at the terminus of pipelines, this research was carried out by setting a series of leakage rate gradients to analyze the influence of different leakage flow rates on iron release, as well as the relationship with chemical and biological parameters. The results showed that the water quality parameters were obviously influenced by the change in flow velocity. Water quality was gradually improved with an increase in flow velocity, but its change regularity reflected a diversity under different flow rates (p water distribution system, when the bulk water was at the critical laminar flow velocity, the concentration of total iron, the quantity and rate of total iron release remain relatively in an ideal and safe situation. Copyright © 2017. Published by Elsevier Ltd.

  17. Improved oxygen-activation method for determining water flow behind casing

    International Nuclear Information System (INIS)

    McKeon, D.C.; Scott, H.D.; Olesen, J.R.; Patton, G.L.; Mitchell, R.J.

    1991-01-01

    This paper reports on impulse activation which is a new oxygen-activation technique developed to detect vertical water flow and to provide a quantitative measure of water flow velocity and flow rate. Flow-loop measurements made over a wide range of water velocities are in good agreement with theoretical predictions. Measurements of up- and downward channel flow were made at the U.S. Environmental Protection Agency (EPA) leak test well in Ada, OK, to demonstrate the technique in a controlled environment and to confirm that EPA requirements have been met. A major advantage of this method over previous procedures is that a measurement is a known zero-flow zone is not required. The impulse-activation technique has improved sensitivity to both low and high flow rates. In the EPA leak test well, the technique successfully discriminated between 0- and 1.4 ft/min flow conditions. The lowest quantified velocity was 1.8 ft/min or 10 BWPD, significantly below the EPA requirement of 3 ft/min. The upper limit of detection has not been determined by exceeds 137 ft/min. The water flow log (WFL SM ) measurement uses the impulse-activation technique and a Dual-Bust SM , thermal-decay-time (TDT SM ) tool to detect water flow behind casing. An important application of this measurement is testing for fluid migration in the wellbore as part of the mechanical integrity testing process for Class I and II disposal wells. The new oxygen-activation measurement was used in numerous production wells to identify the presence of water flow behind casing. Additional applications include the identification of open fractures in horizontal wells and the quantification of water flow in the tubing/casing annulus in injection and production wells

  18. Malignant human cell transformation of Marcellus shale gas drilling flow back water

    OpenAIRE

    Yao, Yixin; Chen, Tingting; Shen, Steven S.; Niu, Yingmei; DesMarais, Thomas L; Linn, Reka; Saunders, Eric; Fan, Zhihua; Lioy, Paul; Kluz, Thomas; Chen, Lung-Chi; Wu, Zhuangchun; Costa, Max

    2015-01-01

    The rapid development of high-volume horizontal hydraulic fracturing for mining natural gas from shale has posed potential impacts on human health and biodiversity. The produced flow back waters after hydraulic stimulation is known to carry high levels of saline and total dissolved solids. To understand the toxicity and potential carcinogenic effects of these waste waters, flow back water from five Marcellus hydraulic fracturing oil and gas wells were analyzed. The physicochemical nature of t...

  19. Importance of vegetation, topography and flow paths for water transit times of base flow in alpine headwater catchments

    Directory of Open Access Journals (Sweden)

    M. H. Mueller

    2013-04-01

    Full Text Available The mean transit time (MTT of water in a catchment gives information about storage, flow paths, sources of water and thus also about retention and release of solutes in a catchment. To our knowledge there are only a few catchment studies on the influence of vegetation cover changes on base flow MTTs. The main changes in vegetation cover in the Swiss Alps are massive shrub encroachment and forest expansion into formerly open habitats. Four small and relatively steep headwater catchments in the Swiss Alps (Ursern Valley were investigated to relate different vegetation cover to water transit times. Time series of water stable isotopes were used to calculate MTTs. The high temporal variation of the stable isotope signals in precipitation was strongly dampened in stream base flow samples. MTTs of the four catchments were 70 to 102 weeks. The strong dampening of the stable isotope input signal as well as stream water geochemistry points to deeper flow paths and mixing of waters of different ages at the catchments' outlets. MTTs were neither related to topographic indices nor vegetation cover. The major part of the quickly infiltrating precipitation likely percolates through fractured and partially karstified deeper rock zones, which increases the control of bedrock flow paths on MTT. Snow accumulation and the timing of its melt play an important role for stable isotope dynamics during spring and early summer. We conclude that, in mountainous headwater catchments with relatively shallow soil layers, the hydrogeological and geochemical patterns (i.e. geochemistry, porosity and hydraulic conductivity of rocks and snow dynamics influence storage, mixing and release of water in a stronger way than vegetation cover or topography do.

  20. Estimation of preferred water flow parameters for four species of ...

    African Journals Online (AJOL)

    Blackfly larvae typically occur in fast-flowing riffle sections of rivers, with different blackfly species showing preferences for different hydraulic conditions. Very little quantitative data exist on hydraulic conditions linked to the blackfly species occurring in South African streams. Stones-in-current biotopes (i.e. fast riffle flows over ...

  1. Ground-water flow in low permeability environments

    Science.gov (United States)

    Neuzil, Christopher E.

    1986-01-01

    Certain geologic media are known to have small permeability; subsurface environments composed of these media and lacking well developed secondary permeability have groundwater flow sytems with many distinctive characteristics. Moreover, groundwater flow in these environments appears to influence the evolution of certain hydrologic, geologic, and geochemical systems, may affect the accumulation of pertroleum and ores, and probably has a role in the structural evolution of parts of the crust. Such environments are also important in the context of waste disposal. This review attempts to synthesize the diverse contributions of various disciplines to the problem of flow in low-permeability environments. Problems hindering analysis are enumerated together with suggested approaches to overcoming them. A common thread running through the discussion is the significance of size- and time-scale limitations of the ability to directly observe flow behavior and make measurements of parameters. These limitations have resulted in rather distinct small- and large-scale approaches to the problem. The first part of the review considers experimental investigations of low-permeability flow, including in situ testing; these are generally conducted on temporal and spatial scales which are relatively small compared with those of interest. Results from this work have provided increasingly detailed information about many aspects of the flow but leave certain questions unanswered. Recent advances in laboratory and in situ testing techniques have permitted measurements of permeability and storage properties in progressively “tighter” media and investigation of transient flow under these conditions. However, very large hydraulic gradients are still required for the tests; an observational gap exists for typical in situ gradients. The applicability of Darcy's law in this range is therefore untested, although claims of observed non-Darcian behavior appear flawed. Two important nonhydraulic

  2. Investigation Of Cross-Flow Model Water Turbine

    International Nuclear Information System (INIS)

    Obretenov, V.S.

    1998-01-01

    The research is made with the basic objective of constructing effective stream section of cross-flow turbine. In the research project are presented the results from experimental testing of the cross-flow turbine with various runner. nozzles and draft tubes. The rotational and universal characteristics of the turbine are presented. The experimental results have been analyzed.The results from the research give the possibility to make clear some important aspects of the working process with the cross-flow turbines. The characteristics derived from these tests prove that the stream section of the tested cross-flow turbine can be used as a model in the construction of cross-flow turbines for power electric stations with small capacity

  3. Numerical study of the air-flow in an oscillating water column wave energy converter

    Energy Technology Data Exchange (ETDEWEB)

    Paixao Conde, J.M. [Department of Mechanical and Industrial Engineering, Faculty of Sciences and Technology, New University of Lisbon, Monte de Caparica, 2829-516 Caparica (Portugal); IDMEC, Instituto Superior Tecnico, Technical University of Lisbon, 1049-001 Lisboa (Portugal); Gato, L.M.C. [IDMEC, Instituto Superior Tecnico, Technical University of Lisbon, 1049-001 Lisboa (Portugal)

    2008-12-15

    The paper presents a numerical study of the air-flow in a typical pneumatic chamber geometry of an oscillating water column (OWC)-type wave energy converter (WEC), equipped with two vertical-axis air turbines, asymmetrically placed on the top of the chamber. Outwards and inwards, steady and periodic, air-flow calculations were performed to investigate the flow distribution at the turbines' inlet sections, as well as the properties of the air-jet impinging on the water free-surface. The original design of the OWC chamber is likely to be harmful for the operation of the turbines due to the possible air-jet-produced water-spray at the water free-surface subsequently ingested by the turbine. A geometry modification of the air chamber, using a horizontal baffle-plate to deflect the air from the turbines, is proposed and proved to be very effective in reducing the risk of water-spray production from the inwards flow. The flow distribution at the turbines' inlet sections for the outwards flow was found to be fairly uniform for the geometries considered, providing good inlet flow conditions for the turbines. Steady flow was found to be an acceptable model to study the air-flow inside the pneumatic chamber of an OWC-WEC. (author)

  4. Magnitude and sign correlations in conductance fluctuations of horizontal oil water two-phase flow

    International Nuclear Information System (INIS)

    Zhu, L; Jin, N D; Gao, Z K; Zong, Y B; Zhai, L S; Wang, Z Y

    2012-01-01

    In experiment we firstly define five typical horizontal oil-water flow patterns. Then we introduce an approach for analyzing signals by decomposing the original signals increment into magnitude and sign series and exploring their scaling properties. We characterize the nonlinear and linear properties of horizontal oil-water two-phase flow, which relate to magnitude and sign series respectively. We find that the joint distribution of different scaling exponents can effectively identify flow patterns, and the detrended fluctuation analysis (DFA) on magnitude and sign series can represent typical horizontal oil-water two-phase flow dynamics characteristics. The results indicate that the magnitude and sign decomposition method can be a helpful tool for characterizing complex dynamics of horizontal oil-water two-phase flow.

  5. Influence of cold-water immersion on limb blood flow after resistance exercise.

    Science.gov (United States)

    Mawhinney, Chris; Jones, Helen; Low, David A; Green, Daniel J; Howatson, Glyn; Gregson, Warren

    2017-06-01

    This study determined the influence of cold (8°C) and cool (22°C) water immersion on lower limb and cutaneous blood flow following resistance exercise. Twelve males completed 4 sets of 10-repetition maximum squat exercise and were then immersed, semi-reclined, into 8°C or 22°C water for 10-min, or rested in a seated position (control) in a randomized order on different days. Rectal and thigh skin temperature, muscle temperature, thigh and calf skin blood flow and superficial femoral artery blood flow were measured before and after immersion. Indices of vascular conductance were calculated (flux and blood flow/mean arterial pressure). The colder water reduced thigh skin temperature and deep muscle temperature to the greatest extent (P lower (55%) than the control post-immersion (P water similarly reduce femoral artery and cutaneous blood flow responses but not muscle temperature following resistance exercise.

  6. Quantifying water flow and retention in an unsaturated fracture-facial domain

    Science.gov (United States)

    Nimmo, John R.; Malek-Mohammadi, Siamak

    2015-01-01

    Hydrologically significant flow and storage of water occur in macropores and fractures that are only partially filled. To accommodate such processes in flow models, we propose a three-domain framework. Two of the domains correspond to water flow and water storage in a fracture-facial region, in addition to the third domain of matrix water. The fracture-facial region, typically within a fraction of a millimeter of the fracture wall, includes a flowing phase whose fullness is determined by the availability and flux of preferentially flowing water, and a static storage portion whose fullness is determined by the local matric potential. The flow domain can be modeled with the source-responsive preferential flow model, and the roughness-storage domain can be modeled with capillary relations applied on the fracture-facial area. The matrix domain is treated using traditional unsaturated flow theory. We tested the model with application to the hydrology of the Chalk formation in southern England, coherently linking hydrologic information including recharge estimates, streamflow, water table fluctuation, imaging by electron microscopy, and surface roughness. The quantitative consistency of the three-domain matrix-microcavity-film model with this body of diverse data supports the hypothesized distinctions and active mechanisms of the three domains and establishes the usefulness of this framework.

  7. Effect of water chemistry improvement on flow accelerated corrosion in light-water nuclear reactor

    International Nuclear Information System (INIS)

    Sugino, Wataru; Ohira, Taku; Nagata, Nobuaki; Abe, Ayumi; Takiguchi, Hideki

    2009-01-01

    Flow Accelerated Corrosion (FAC) of Carbon Steel (CS) piping has been one of main issues in Light-Water Nuclear Reactor (LWRs). Wall thinning of CS piping due to FAC increases potential risk of pipe rupture and cost for inspection and replacement of damaged pipes. In particular, corrosion products generated by FAC of CS piping brought steam generator (SG) tube corrosion and degradation of thermal performance, when it intruded and accumulated in secondary side of PWR. To preserve SG integrity by suppressing the corrosion of CS, High-AVT chemistry (Feedwater pH9.8±0.2) has been adopted to Tsuruga-2 (1160 MWe PWR, commercial operation in 1987) in July 2005 instead of conventional Low-AVT chemistry (Feedwater pH 9.3). By the High-AVT adoption, the accumulation rate of iron in SG was reduced to one-quarter of that under conventional Low-AVT. As a result, a tendency to degradation of the SG thermal efficiency was improved. On the other hand, it was clarified that High-AVT is ineffective against Flow Accelerated Corrosion (FAC) at the region where the flow turbulence is much larger. By contrast, wall thinning of CS feed water pipes due to FAC has been successfully controlled by oxygen treatment (OT) for long time in BWRs. Because Magnetite film formed on CS surface under AVT chemistry has higher solubility and porosity in comparison with Hematite film, which is formed under OT. In this paper, behavior of the FAC under various pH and dissolved oxygen concentration are discussed based on the actual wall thinning rate of BWR and PWR plant and experimental results by FAC test-loop. And, it is clarified that the FAC is suppressed even under extremely low DO concentration such as 2ppb under AVT condition in PWR. Based on this result, we propose the oxygenated water chemistry (OWC) for PWR secondary system which can mitigate the FAC of CS piping without any adverse effect for the SG integrity. Furthermore, the applicability and effectiveness of this concept developed for FAC

  8. Characterising Dynamic Instability in High Water-Cut Oil-Water Flows Using High-Resolution Microwave Sensor Signals

    Science.gov (United States)

    Liu, Weixin; Jin, Ningde; Han, Yunfeng; Ma, Jing

    2018-06-01

    In the present study, multi-scale entropy algorithm was used to characterise the complex flow phenomena of turbulent droplets in high water-cut oil-water two-phase flow. First, we compared multi-scale weighted permutation entropy (MWPE), multi-scale approximate entropy (MAE), multi-scale sample entropy (MSE) and multi-scale complexity measure (MCM) for typical nonlinear systems. The results show that MWPE presents satisfied variability with scale and anti-noise ability. Accordingly, we conducted an experiment of vertical upward oil-water two-phase flow with high water-cut and collected the signals of a high-resolution microwave resonant sensor, based on which two indexes, the entropy rate and mean value of MWPE, were extracted. Besides, the effects of total flow rate and water-cut on these two indexes were analysed. Our researches show that MWPE is an effective method to uncover the dynamic instability of oil-water two-phase flow with high water-cut.

  9. High performance in low-flow solar domestic hot water systems

    Energy Technology Data Exchange (ETDEWEB)

    Dayan, M.

    1997-12-31

    Low-flow solar hot water heating systems employ flow rates on the order of 1/5 to 1/10 of the conventional flow. Low-flow systems are of interest because the reduced flow rate allows smaller diameter tubing, which is less costly to install. Further, low-flow systems result in increased tank stratification. Lower collector inlet temperatures are achieved through stratification and the useful energy produced by the collector is increased. The disadvantage of low-flow systems is the collector heat removal factor decreases with decreasing flow rate. Many solar domestic hot water systems require an auxiliary electric source to operate a pump in order to circulate fluid through the solar collector. A photovoltaic driven pump can be used to replace the standard electrical pump. PV driven pumps provide an ideal means of controlling the flow rate, as pumps will only circulate fluid when there is sufficient radiation. Peak performance was always found to occur when the heat exchanger tank-side flow rate was approximately equal to the average load flow rate. For low collector-side flow rates, a small deviation from the optimum flow rate will dramatically effect system performance.

  10. Water-Level Data Analysis for the Saturated Zone Site-Scale Flow and Transport Model

    International Nuclear Information System (INIS)

    Tucci, P.

    2001-01-01

    This Analysis/Model Report (AMR) documents an updated analysis of water-level data performed to provide the saturated-zone, site-scale flow and transport model (CRWMS M and O 2000) with the configuration of the potentiometric surface, target water-level data, and hydraulic gradients for model calibration. The previous analysis was presented in ANL-NBS-HS-000034, Rev 00 ICN 01, Water-Level Data Analysis for the Saturated Zone Site-Scale Flow and Transport Model (USGS 2001). This analysis is designed to use updated water-level data as the basis for estimating water-level altitudes and the potentiometric surface in the SZ site-scale flow and transport model domain. The objectives of this revision are to develop computer files containing (1) water-level data within the model area (DTN: GS010908312332.002), (2) a table of known vertical head differences (DTN: GS0109083 12332.003), and (3) a potentiometric-surface map (DTN: GS010608312332.001) using an alternate concept from that presented in ANL-NBS-HS-000034, Rev 00 ICN 01 for the area north of Yucca Mountain. The updated water-level data include data obtained from the Nye County Early Warning Drilling Program (EWDP) and data from borehole USW WT-24. In addition to being utilized by the SZ site-scale flow and transport model, the water-level data and potentiometric-surface map contained within this report will be available to other government agencies and water users for ground-water management purposes. The potentiometric surface defines an upper boundary of the site-scale flow model, as well as provides information useful to estimation of the magnitude and direction of lateral ground-water flow within the flow system. Therefore, the analysis documented in this revision is important to SZ flow and transport calculations in support of total system performance assessment

  11. Examples of detection of water flow by oxygen activation on pulsed neutron logs

    International Nuclear Information System (INIS)

    de Rosset, W.H.M.

    1986-01-01

    Upward flow of water in cased wellbores may be detected with pulsed neutron capture (PNC) and gamma ray (GR) tools. Water entering tubing, casing and flowing behind pipe may similarly be evaluated qualitatively. Gamma ray background anomalies in PNC data and elevation of GR tool response occur when water is flowing above threshold velocities and volumes. The technique requires logging the well under static and flow conditions or logging at different tools speeds in a flowing well. Oxygen activation results in increased gamma ray count rates at each detector. PNC far detector and GR well log curves from each log run (flowing well, static well) are overlain. The increases for each curve are offset from the point of water entry by a distance similar to tool source-detector spacing. These offsets in gamma increase are 15-20 ft. higher for the GR than for the PNC far detector and distinguish oxygen activation due to flowing water from common hot spots. The amount of gamma ray increase is controlled by the velocity of upward flow of water past the tool, the amount of water flowing, and the distance of the flow from the tool. Prior planning is important to gain usable information in flowing wells. The upward relative velocity imposes maximal and minimal tool speeds to produce significant gamma increases, and tool speed must be adjusted to optimize gamma changes. Use of the technique to answer actual production problems is illustrated with examples. Insight was gained which led to the correction of the problem in each case

  12. Water Pipeline Network Analysis Using Simultaneous Loop Flow ...

    African Journals Online (AJOL)

    2013-03-01

    Mar 1, 2013 ... *Department of Mechanical Engineering, Michael Okpara University of Agriculture, Umudike, Nigeria ... significant fluid acceleration, the behavior of a network can be ... world water day centers on water and food security as.

  13. Experimental study of flow monitoring instruments in air-water, two-phase downflow

    International Nuclear Information System (INIS)

    Sheppard, J.D.; Hayes, P.H.; Wynn, M.C.

    1976-01-01

    The performance of a turbine meter, target flow meter (drag disk), and a gamma densitometer was studied in air-water, two-phase vertical downflow. Air and water were metered into an 0.0889-m-ID (3.5-in.) piping system; air flows ranged from 0.007 to 0.3 m 3 /sec (16 to 500 scfm) and water flows ranged from 0.0006 to 0.03 m 3 /sec (10 to 500 gpm). The study included effects of flow rate, quality, flow regime, and flow dispersion on the mean and fluctuating components of the instrument signals. Wire screen flow dispersers located at the inlet to the test section had a significant effect on the readings of the drag disk and gamma densitometer, but had little effect on the turbine. Further, when flow dispersers were used, mass flow rates determined from the three instrument readings and a two-velocity, slip flow model showed good agreement with actual mass flow rate over a three-fold range in quality; mass flows determined with the drag disk and densitometer readings assuming homogeneous flow were nearly as accurate. However, when mass flows were calculated using the turbine and densitometer or turbine and drag disk readings assuming homogeneous flow, results were scattered and relatively inaccurate compared to the actual mass flows. Turbine meter data were used with a two-velocity turbine model and continuity relationships for each phase to determine the void fraction and mean phase velocities in the test section. The void fraction was compared with single beam gamma densitometer results and fluid momentum calculated from a two-velocity model was compared with drag disk readings

  14. Science of Water Leaks: Validated Theory for Moisture Flow in Microchannels and Nanochannels.

    Science.gov (United States)

    Lei, Wenwen; Fong, Nicole; Yin, Yongbai; Svehla, Martin; McKenzie, David R

    2015-10-27

    Water is ubiquitous; the science of its transport in micro- and nanochannels has applications in electronics, medicine, filtration, packaging, and earth and planetary science. Validated theory for water vapor and two-phase water flows is a "missing link"; completing it enables us to define and quantify flow in a set of four standard leak configurations with dimensions from the nanoscale to the microscale. Here we report the first measurements of water vapor flow rates through four silica microchannels as a function of humidity, including under conditions when air is present as a background gas. An important finding is that the tangential momentum accommodation coefficient (TMAC) is strongly modified by surface layers of adsorbed water molecules, in agreement with previous work on the TMAC for nitrogen molecules impacting a silica surface in the presence of moisture. We measure enhanced flow rates for two-phase flows in silica microchannels driven by capillary filling. For the measurement of flows in nanochannels we use heavy water mass spectrometry. We construct the theory for the flow rates of the dominant modes of water transport through each of the four standard configurations and benchmark it against our new measurements in silica and against previously reported measurements for nanochannels in carbon nanotubes, carbon nanopipes, and porous alumina. The findings show that all behavior can be described by the four standard leak configurations and that measurements of leak behavior made using other molecules, such as helium, are not reliable. Single-phase water vapor flow is overestimated by a helium measurement, while two-phase flows are greatly underestimated for channels larger than 100 nm or for all channels when boundary slip applies, to an extent that depends on the slip length for the liquid-phase flows.

  15. Assessment of regional trade and virtual water flows in China

    OpenAIRE

    Dabo, G.; Hubacek, K.

    2007-01-01

    The success of Chinas economic development has left deep marks on resource availability and quality. Some regions in China are relatively poor with regards to water resources. This problem is exacerbated by economic growth. Flourishing trade activities on both domestic and international levels have resulted in significant amounts of water withdrawal and water pollution. Hence the goal of this paper is to evaluate the current inter-regional trade structure and its effects on water consumption ...

  16. The role of scarcity in global virtual water flows

    OpenAIRE

    Lenzen, Manfred; Bhaduri, Anik; Moran, Daniel; Kanemoto, Keiichiro; Bekchanov, Maksud

    2012-01-01

    Recent analyses of the evolution and structure of trade in virtual water revealed that the number of trade connections and volume of virtual water trade have more than doubled over the past two decades, and that developed countries increasingly draw on the rest of the world to alleviate the pressure on their domestic water resources. Our work builds on these studies, but fills three important gaps in the research on global virtual water trade. First, we note that in previous studies virtual w...

  17. Water-powder mixtures at the onset of flowing

    NARCIS (Netherlands)

    Hunger, M.; Brouwers, H.J.H.; Al-Mattarneh, H.; Mustapha, K.N.; Nuruddin, M.F.

    2008-01-01

    The knowledge of water demands of the manifold concrete ingredients is of vital interest for the design of concrete mixes. Physical properties like workability or strength and durability in hardened state are controlled by the total water content. Water demand is defined as the volumetric ratio of

  18. Modelling of flow and settling in storm water sedimentation tanks

    NARCIS (Netherlands)

    Kluck, J.

    1994-01-01

    In the near future in the Netherlands many reservoirs will have to be built to abate the pollution of the surface water by overflowing storm water from combined sewer systems [Kluck, 1992-a]. These reservoirs, called storm water sedimentation tanks, reduce the pollution in two ways. The most

  19. Human well-being values of environmental flows enhancing social equity in integrated water resources management

    NARCIS (Netherlands)

    Meijer, K.S.

    2007-01-01

    This dissertation discusses how the importance of river flow-sustained ecosystems for local communities can be quantified for the purpose of balancing water supply and demand in Integrated Water Resources Management. Due to the development of water resources, for example through the construction of

  20. Implications of Upstream Flow Availability for Watershed Surface Water Supply Across the Conterminous United States

    Science.gov (United States)

    Kai Duan; Ge Sun; Peter V. Caldwell; Steven G. McNulty; Yang Zhang

    2018-01-01

    Although it is well established that the availability of upstream flow (AUF) affects downstream water supply, its significance has not been rigorously categorized and quantified at fine resolutions. This study aims to fill this gap by providing a nationwide inventory of AUF and local water resource, and assessing their roles in securing water supply across the 2,099 8-...

  1. A flow balance approach to scenarios for water reclamation by Ania ...

    African Journals Online (AJOL)

    drinie

    ISSN 0378-4738 = Water SA Vol. 27 No. 1 January 2001 115. Available on website http://www.wrc.org.za. Comments on: A flow balance approach to scenarios for water reclamation by Ania MW Grobicki and B Cohen. I would like to offer a brief comment on the above paper, which appeared in Water SA 25 (4), October ...

  2. Core Flow Distribution from Coupled Supercritical Water Reactor Analysis

    Directory of Open Access Journals (Sweden)

    Po Hu

    2014-01-01

    Full Text Available This paper introduces an extended code package PARCS/RELAP5 to analyze steady state of SCWR US reference design. An 8 × 8 quarter core model in PARCS and a reactor core model in RELAP5 are used to study the core flow distribution under various steady state conditions. The possibility of moderator flow reversal is found in some hot moderator channels. Different moderator flow orifice strategies, both uniform across the core and nonuniform based on the power distribution, are explored with the goal of preventing the reversal.

  3. VOF modelling of gas–liquid flow in PEM water electrolysis cell micro-channels

    DEFF Research Database (Denmark)

    Lafmejani, Saeed Sadeghi; Olesen, Anders Christian; Kær, Søren Knudsen

    2017-01-01

    In this study, the gaseliquid flow through an interdigitated anode flow field of a PEM water electrolysis cell (PEMEC) is analysed using a three-dimensional, transient, computational fluid dynamics (CFD) model. To account for two-phase flow, the volume of fluid (VOF) method in ANSYS Fluent 17...... of the channel. The model is capable of revealing effect of different bubble shapes/lengths in the outgoing channel. Shape and the sequence of the bubbles affect the water flow distribution in the ATL. The model presented in this work is the first step in the development of a comprehensive CFD model...

  4. Fire flow water consumption in sprinklered and unsprinklered buildings an assessment of community impacts

    CERN Document Server

    Code Consultants, Inc.

    2012-01-01

    Fire Flow Water Consumption in Sprinklered and Unsprinklered Buildings offers a detailed analysis for calculating the fire water demand required in buildings with existing and non-existant sprinkler systems. The installation of automatic sprinkler systems can significantly reduce the amount of water needed during a fire, but it requires water for commissioning, inspection, testing, and maintenance (CITM). This book provides an estimate of fire water used under both fire conditions, including CITM, to allow communities to develop fire water fees for both sprinklered and unsprinklered buildings that are proportional to the anticipated fire water usage. The types of buildings analyzed include residential (family dwellings as well as those up to four stories in height), business, assembly, institutional, mercantile, and storage facilities. Water volume was studied using guidelines from the International Code Council, the National Fire Protection Association, and the Insurance Services Office. Fire Flow Water Cons...

  5. Fluid-elastic instability in tube arrays subjected to air-water and steam-water cross-flow

    Science.gov (United States)

    Mitra, D.; Dhir, V. K.; Catton, I.

    2009-10-01

    Flow induced vibrations in heat exchanger tubes have led to numerous accidents and economic losses in the past. Efforts have been made to systematically study the cause of these vibrations and develop remedial design criteria for their avoidance. In this research, experiments were systematically carried out with air-water and steam-water cross-flow over horizontal tubes. A normal square tube array of pitch-to-diameter ratio of 1.4 was used in the experiments. The tubes were suspended from piano wires and strain gauges were used to measure the vibrations. Tubes made of aluminum; stainless steel and brass were systematically tested by maintaining approximately the same stiffness in the tube-wire systems. Instability was clearly seen in single phase and two-phase flow and the critical flow velocity was found to be proportional to tube mass. The present study shows that fully flexible arrays become unstable at a lower flow velocity when compared to a single flexible tube surrounded by rigid tubes. It is also found that tubes are more stable in steam-water flow as compared to air-water flow. Nucleate boiling on the tube surface is also found to have a stabilizing effect on fluid-elastic instability.

  6. Miniaturized Water Flow and Level Monitoring System for Flood Disaster Early Warning

    Science.gov (United States)

    Ifedapo Abdullahi, Salami; Hadi Habaebi, Mohamed; Surya Gunawan, Teddy; Rafiqul Islam, MD

    2017-11-01

    This study presents the performance of a prototype miniaturised water flow and water level monitoring sensor designed towards supporting flood disaster early warning systems. The design involved selection of sensors, coding to control the system mechanism, and automatic data logging and storage. During the design phase, the apparatus was constructed where all the components were assembled using locally sourced items. Subsequently, under controlled laboratory environment, the system was tested by running water through the inlet during which the flow rate and rising water levels are automatically recorded and stored in a database via Microsoft Excel using Coolterm software. The system is simulated such that the water level readings measured in centimeters is output in meters using a multiplicative of 10. A total number of 80 readings were analyzed to evaluate the performance of the system. The result shows that the system is sensitive to water level rise and yielded accurate measurement of water level. But, the flow rate fluctuates due to the manual water supply that produced inconsistent flow. It was also observed that the flow sensor has a duty cycle of 50% of operating time under normal condition which implies that the performance of the flow sensor is optimal.

  7. Flow cytometry total cell counts : A field study assessing microbiological water quality and growth in unchlorinated drinking water distribution systems

    NARCIS (Netherlands)

    Liu, G.; Van der Mark, E.J.; Verberk, J.Q.; Van Dijk, J.C.

    2013-01-01

    e objective of this study was to evaluate the application of flow cytometry total cell counts (TCCs) as a parameter to assess microbial growth in drinking water distribution systems and to determine the relationships between different parameters describing the biostability of treated water. A

  8. Pattern transitions of oil-water two-phase flow with low water content in rectangular horizontal pipes probed by terahertz spectrum.

    Science.gov (United States)

    Feng, Xin; Wu, Shi-Xiang; Zhao, Kun; Wang, Wei; Zhan, Hong-Lei; Jiang, Chen; Xiao, Li-Zhi; Chen, Shao-Hua

    2015-11-30

    The flow-pattern transition has been a challenging problem in two-phase flow system. We propose the terahertz time-domain spectroscopy (THz-TDS) to investigate the behavior underlying oil-water flow in rectangular horizontal pipes. The low water content (0.03-2.3%) in oil-water flow can be measured accurately and reliably from the relationship between THz peak amplitude and water volume fraction. In addition, we obtain the flow pattern transition boundaries in terms of flow rates. The critical flow rate Qc of the flow pattern transitions decreases from 0.32 m3 h to 0.18 m3 h when the corresponding water content increases from 0.03% to 2.3%. These properties render THz-TDS particularly powerful technology for investigating a horizontal oil-water two-phase flow system.

  9. Computational Flow Dynamic Simulation of Micro Flow Field Characteristics Drainage Device Used in the Process of Oil-Water Separation

    Directory of Open Access Journals (Sweden)

    Guangya Jin

    2017-01-01

    Full Text Available Aqueous crude oil often contains large amounts of produced water and heavy sediment, which seriously threats the safety of crude oil storage and transportation. Therefore, the proper design of crude oil tank drainage device is prerequisite for efficient purification of aqueous crude oil. In this work, the composition and physicochemical properties of crude oil samples were tested under the actual conditions encountered. Based on these data, an appropriate crude oil tank drainage device was developed using the principle of floating ball and multiphase flow. In addition, the flow field characteristics in the device were simulated and the contours and streamtraces of velocity magnitude at different nine moments were obtained. Meanwhile, the improvement of flow field characteristics after the addition of grids in crude oil tank drainage device was validated. These findings provide insights into the development of effective selection methods and serve as important references for oil-water separation process.

  10. Isotope Compositions Of Mekong River Flow Water In The South Of Vietnam

    International Nuclear Information System (INIS)

    Nguyen Kien Chinh; Huynh Long; Le Danh Chuan; Nguyen Van Nhien; Tran Thi Bich Lien

    2008-01-01

    As a part of the Research Contract No. VIE/12569, isotope composition of Mekong river flow water in the South of Vietnam has been monitored to provide information on water origin and residence times, surface-groundwater exchange in the monitoring area. According to the primary results obtained, a seasonal variation as well as the dependence on local precipitation and on the river water level of isotopic composition of two distributaries of Mekong river water have been observed. At the same time a slight change on season of tritium in rivers water and the difference between tritium content in local rainy water and river water has been recorded. (author)

  11. Scaling-Laws of Flow Entropy with Topological Metrics of Water Distribution Networks

    Directory of Open Access Journals (Sweden)

    Giovanni Francesco Santonastaso

    2018-01-01

    Full Text Available Robustness of water distribution networks is related to their connectivity and topological structure, which also affect their reliability. Flow entropy, based on Shannon’s informational entropy, has been proposed as a measure of network redundancy and adopted as a proxy of reliability in optimal network design procedures. In this paper, the scaling properties of flow entropy of water distribution networks with their size and other topological metrics are studied. To such aim, flow entropy, maximum flow entropy, link density and average path length have been evaluated for a set of 22 networks, both real and synthetic, with different size and topology. The obtained results led to identify suitable scaling laws of flow entropy and maximum flow entropy with water distribution network size, in the form of power–laws. The obtained relationships allow comparing the flow entropy of water distribution networks with different size, and provide an easy tool to define the maximum achievable entropy of a specific water distribution network. An example of application of the obtained relationships to the design of a water distribution network is provided, showing how, with a constrained multi-objective optimization procedure, a tradeoff between network cost and robustness is easily identified.

  12. Strong Flows of Bottom Water in Abyssal Channels of the Atlantic

    Science.gov (United States)

    Morozov, E. G.

    Analysis of bottom water transport through the abyssal channels of the Atlantic Ocean is presented. The study is based on recent observations in the Russian expeditions and historical data. A strong flow of Antarctic Bottom Water from the Argentine Basin to the Brazil Basin through the Vema Channel is observed on the basis of lowered profilers and anchored buoys with current meters. The further flow of bottom water in the Brazil Basin splits in the northern part of the basin. Part of the bottom water flows to the East Atlantic through the Romanche and Chain fracture zones. The other part follows the bottom topography and flows to the northwester into the North American Basin. Part of the northwesterly flow propagates through the Vema Fracture Zone into the Northeastern Atlantic. This flow generally fills the bottom layer in the Northeastern Atlantic basins. The flows of bottom waters through the Romanche and Chain fracture zones do not spread to the Northeast Atlantic due to strong mixing in the equatorial zone and enhanced transformation of bottom water properties.

  13. Structure of two-phase air-water flows. Study of average void fraction and flow patterns

    International Nuclear Information System (INIS)

    Roumy, R.

    1969-01-01

    This report deals with experimental work on a two phase air-water mixture in vertical tubes of different diameters. The average void fraction was measured in a 2 metre long test section by means of quick-closing valves. Using resistive probes and photographic techniques, we have determined the flow patterns and developed diagrams to indicate the boundaries between the various patterns: independent bubbles, agglomerated bubbles, slugs, semi-annular, annular. In the case of bubble flow and slug flow, it is shown that the relationship between the average void fraction and the superficial velocities of the phases is given by: V sg = f( ) * g(V sl ). The function g(V sl ) for the case of independent bubbles has been found to be: g(V sl ) = V sl + 20. For semi-annular and annular flow conditions; it appears that the average void fraction depends, to a first approximation only on the ratio V sg /V sl . (author) [fr

  14. Simulation of Ground-Water Flow and Effects of Ground-Water Irrigation on Base Flow in the Elkhorn and Loup River Basins, Nebraska

    Science.gov (United States)

    Peterson, Steven M.; Stanton, Jennifer S.; Saunders, Amanda T.; Bradley, Jesse R.

    2008-01-01

    Irrigated agriculture is vital to the livelihood of communities in the Elkhorn and Loup River Basins in Nebraska, and ground water is used to irrigate most of the cropland. Concerns about the sustainability of ground-water and surface-water resources have prompted State and regional agencies to evaluate the cumulative effects of ground-water irrigation in this area. To facilitate understanding of the effects of ground-water irrigation, a numerical computer model was developed to simulate ground-water flow and assess the effects of ground-water irrigation (including ground-water withdrawals, hereinafter referred to as pumpage, and enhanced recharge) on stream base flow. The study area covers approximately 30,800 square miles, and includes the Elkhorn River Basin upstream from Norfolk, Nebraska, and the Loup River Basin upstream from Columbus, Nebraska. The water-table aquifer consists of Quaternary-age sands and gravels and Tertiary-age silts, sands, and gravels. The simulation was constructed using one layer with 2-mile by 2-mile cell size. Simulations were constructed to represent the ground-water system before 1940 and from 1940 through 2005, and to simulate hypothetical conditions from 2006 through 2045 or 2055. The first simulation represents steady-state conditions of the system before anthropogenic effects, and then simulates the effects of early surface-water development activities and recharge of water leaking from canals during 1895 to 1940. The first simulation ends at 1940 because before that time, very little pumpage for irrigation occurred, but after that time it became increasingly commonplace. The pre-1940 simulation was calibrated against measured water levels and estimated long-term base flow, and the 1940 through 2005 simulation was calibrated against measured water-level changes and estimated long-term base flow. The calibrated 1940 through 2005 simulation was used as the basis for analyzing hypothetical scenarios to evaluate the effects of

  15. Understanding virtual water flows: A multiregion input-output case study of Victoria

    Science.gov (United States)

    Lenzen, Manfred

    2009-09-01

    This article explains and interprets virtual water flows from the well-established perspective of input-output analysis. Using a case study of the Australian state of Victoria, it demonstrates that input-output analysis can enumerate virtual water flows without systematic and unknown truncation errors, an issue which has been largely absent from the virtual water literature. Whereas a simplified flow analysis from a producer perspective would portray Victoria as a net virtual water importer, enumerating the water embodiments across the full supply chain using input-output analysis shows Victoria as a significant net virtual water exporter. This study has succeeded in informing government policy in Australia, which is an encouraging sign that input-output analysis will be able to contribute much value to other national and international applications.

  16. Computer modelling of a linear turbine for extracting energy from slow-flowing waters

    International Nuclear Information System (INIS)

    Raykov, Plamen

    2014-01-01

    The aim of the paper is to describe the main relationships in the process of designing linear chain turbines with blades and their accompanying devices for obtaining energy from slow flowing waters. Based on the shortcomings of previous types of linear turbines a new concept for arrangement of the blades angles with respect to the flowing water was developed. The dependencies of the geometrical parameters of designed new type linear water turbine and the force applied by the flowing water to the blades are obtained. The optimal relationship between velocity of stream water and extracted power is calculated. The ratio between power characteristics of the extracted energy for different speeds of blades and inclination angle are presented. On the basis of the theoretical results a new linear turbine prototype with inclined blades was designed. Key words: water power system, blade-chain devices, linear turbines

  17. Entropy Production in Pipeline Flow of Dispersions of Water in Oil

    Directory of Open Access Journals (Sweden)

    Rajinder Pal

    2014-08-01

    Full Text Available Entropy production in pipeline adiabatic flow of water-in-oil emulsions is investigated experimentally in three different diameter pipes. The dispersed-phase (water droplets concentration of emulsion is varied from 0 to 41% vol. The entropy production rates in emulsion flow are compared with the values expected in single-phase flow of Newtonian fluids with the same properties (viscosity and density. While in the laminar regime the entropy production rates in emulsion flow can be described adequately by the single-phase Newtonian equations, a significant deviation from single-phase flow behavior is observed in the turbulent regime. In the turbulent regime, the entropy production rates in emulsion flow are found to be substantially smaller than those expected on the basis of single-phase equations. For example, the entropy production rate in water-in-oil emulsion flow at a dispersed-phase volume fraction of 0.41 is only 38.4% of that observed in flow of a single-phase Newtonian fluid with the same viscosity and density, when comparison is made at a Reynolds number of 4000. Thus emulsion flow in pipelines is more efficient thermodynamically than single-phase Newtonian flow.

  18. Linking Flow Regime and Water Quality in Rivers: a Challenge to Adaptive Catchment Management

    Directory of Open Access Journals (Sweden)

    Christer Nilsson

    2008-12-01

    Full Text Available Water quality describes the physicochemical characteristics of the water body. These vary naturally with the weather and with the spatiotemporal variation of the water flow, i.e., the flow regime. Worldwide, biota have adapted to the variation in these variables. River channels and their riparian zones contain a rich selection of adapted species and have been able to offer goods and services for sustaining human civilizations. Many human impacts on natural riverine environments have been destructive and present opportunities for rehabilitation. It is a big challenge to satisfy the needs of both humans and nature, without sacrificing one or the other. New ways of thinking, new policies, and institutional commitment are needed to make improvements, both in the ways water flow is modified in rivers by dam operations and direct extractions, and in the ways runoff from adjacent land is affected by land-use practices. Originally, prescribed flows were relatively static, but precepts have been developed to encompass variation, specifically on how water could be shared over the year to become most useful to ecosystems and humans. A key aspect is how allocations of water interact with physicochemical variation of water. An important applied question is how waste releases and discharge can be managed to reduce ecological and sanitary problems that might arise from inappropriate combinations of flow variation and physicochemical characteristics of water. We review knowledge in this field, provide examples on how the flow regime and the water quality can impact ecosystem processes, and conclude that most problems are associated with low-flow conditions. Given that reduced flows represent an escalating problem in an increasing number of rivers worldwide, managers are facing enormous challenges.

  19. Velocity measurements and identification of the flow pattern of vertical air-water flows with light-beam detectors

    International Nuclear Information System (INIS)

    Luebbesmeyer, D.; Leoni, B.

    1980-07-01

    A new detector for measuring fluid velocities in two-phase flows by means of Noise-Analysis (especially Transient-Cross-Correlation-technique) has been developed. The detector utilizes a light-beam which is modulated by changes in the transparency of the two-phase flow. The results of nine measurements for different flow-regimes of vertical air/water-flows are shown. A main topic of these investigations was to answer the question if it is possible to identify the flow-pattern by looking at the shape of different 'Noise-Analytical-functions' (like APSD, CPSD, CCF etc.). The results prove that light-beam sensors are good detectors for fluid-velocity measurements in different flow regimes and in a wide range of fluid velocities starting with values of about 0.08 m/s up to values of 40 m/s. With respect to flow-pattern identification only the time-signals and the shape of the cross-power-density-function (CPSD) seem to be useful. (Auth.)

  20. Topology and stability of a water-soybean-oil swirling flow

    Science.gov (United States)

    Carrión, Luis; Herrada, Miguel A.; Shtern, Vladimir N.

    2017-02-01

    This paper reveals and explains the flow topology and instability hidden in an experimental study by Tsai et al. [Tsai et al., Phys. Rev. E 92, 031002(R) (2015)], 10.1103/PhysRevE.92.031002. Water and soybean oil fill a sealed vertical cylindrical container. The rotating top disk induces the meridional circulation and swirl of both fluids. The experiment shows a flattop interface shape and vortex breakdown in the oil flow developing as the rotation strength R eo increases. Our numerical study shows that vortex breakdown occurs in the water flow at R eo=300 and in the oil flow at R eo=941 . As R eo increases, the vortex breakdown cell occupies most of the water domain and approaches the interface at R eo around 600. The rest of the (countercirculating) water separates from the axis as the vortex breakdown cells in the oil and water meet at the interface-axis intersection. This topological transformation of water flow significantly contributes to the development of the flattop shape. It is also shown that the steady axisymmetric flow suffers from shear-layer instability, which emerges in the water domain at R eo=810 .

  1. Experimental And Numerical Investigation Of The Flow Analysis Of The Water-Saving Safety Valve

    Directory of Open Access Journals (Sweden)

    Muhammed Safa Kamer

    2015-08-01

    Full Text Available Abstract In this study an auto-mechanical safety valve was designed and manufactured in order to prevent possible wastage of water and water raid after instantaneous water cuts during water usage in places where water use is widespread. Safety valve is activated and it switches off the line when water is cut off when mains pressure is equal to atmospheric pressure and as it does not allow water to pass when it comes back it saves water and prevents the formation of raids. An experiment set was conducted in order to measure the pressure drop between the inlet and outlet of the safety valve and it was found that with the increased flow rate the pressure drop increases. The three-dimensional flow analysis of the safety valve was carried out with Ansys-Fluent software package and the results obtained were compared with experimental data and a good harmony was achieved.

  2. Water Flow in Karst Aquifer Considering Dynamically Variable Saturation Conduit

    Science.gov (United States)

    Tan, Chaoqun; Hu, Bill X.

    2017-04-01

    The karst system is generally conceptualized as dual-porosity system, which is characterized by low conductivity and high storage continuum matrix and high conductivity and quick flow conduit networks. And so far, a common numerical model for simulating flow in karst aquifer is MODFLOW2005-CFP, which is released by USGS in 2008. However, the steady-state approach for conduit flow in CFP is physically impractical when simulating very dynamic hydraulics with variable saturation conduit. So, we adopt the method proposed by Reimann et al. (2011) to improve current model, in which Saint-Venant equations are used to model the flow in conduit. Considering the actual background that the conduit is very big and varies along flow path and the Dirichlet boundary varies with rainfall in our study area in Southwest China, we further investigate the influence of conduit diameter and outflow boundary on numerical model. And we also analyze the hydraulic process in multi-precipitation events. We find that the numerical model here corresponds well with CFP for saturated conduit, and it could depict the interaction between matrix and conduit during very dynamic hydraulics pretty well compare with CFP.

  3. Water flow measurements with the pulsed neutron activation method

    International Nuclear Information System (INIS)

    Linden, P.

    1997-05-01

    The objective of this work was to develop and study the feasibility of a flow-meter, based on the pulsed neutron activation method. It is a non-invasive method with good potential regarding accuracy. However, the ultimate accuracy has not been fully investigated before. Two series of flow rate measurements have been performed and analysed. The first series was done under moderately accurate flow calibration conditions to get sufficient confidence in the method and to get indication of the obtainable accuracy. The results were encouraging and further measurements with high accuracy flow calibration were planned. A dedicated loop was designed and built, and it was used with satisfactory performance. Two models have been used for analysis of recorded data; time weighting method and a fit to Taylor diffusion theory. The results show that the accuracy in mean flow velocity obtained from the used analysis models is in the range of 2-4% for Reynolds numbers greater than 10,000. Data recorded from high calibration measurements will also be used for validation of future calculations. 19 refs, 4 figs

  4. Computer programs for the numerical modelling of water flow in rock masses

    International Nuclear Information System (INIS)

    Croney, P.; Richards, L.R.

    1985-08-01

    Water flow in rock joints provides a very important possible route for the migration of radio-nuclides from radio-active waste within a repository back to the biosphere. Two computer programs DAPHNE and FPM have been developed to model two dimensional fluid flow in jointed rock masses. They have been developed to run on microcomputer systems suitable for field locations. The fluid flows in a number of jointed rock systems have been examined and certain controlling functions identified. A methodology has been developed for assessing the anisotropic permeability of jointed rock. A number of examples of unconfined flow into surface and underground openings have been analysed and ground water lowering, pore water pressures and flow quantities predicted. (author)

  5. QUANTIFICATION OF INSTREAM FLOW NEEDS OF A WILD AND SCENIC RIVER FOR WATER RIGHTS LITIGATION.

    Science.gov (United States)

    Garn, Herbert S.

    1986-01-01

    The lower 4 miles of the Red River, a tributary of the Rio Grande in northern New Mexico, was designated as one of the 'instant' components of the National Wild and Scenic River System in 1968. Instream flow requirements were determined by several methods to quantify the claims made by the United States for a federal reserved water right under the Wild and Scenic Rivers Act. The scenic (aesthetic), recreational, and fish and wildlife values are the purposes for which instream flow requirements were claimed. Since water quality is related to these values, instream flows for waste transport and protection of water quality were also included in the claim. The U. S. Fish and Wildlife Service's Instream Flow Incremental Methodology was used to quantify the relationship between various flow regimes and fish habitat. Study results are discussed.

  6. Macropore-mesopore model of water flow through aggregated porous media

    International Nuclear Information System (INIS)

    Fong, L.; Appelbaum, H.R.

    1980-12-01

    A combined, one-dimensional, macropore-mesopore, hydrologic model was developed for simulating water flow through soils for analysis of data related to water and chemical flow in soils. Flows within the macroporous system as well as interactive flows between macroporous and mesoporous systems were modeled. Computer subroutines were written and incorporated into the existing one-dimensional Terrestrial Ecosystem Hydrologic Model (TEHM) developed at ORNL. Simulation showed that macropore flow effects are important during heavy precipitation and are more significant in soils of comparatively low hydraulic conductivity (5 to 10 cm/d). Increased drainage and decreased lateral flow result from the addition of the macropore model. The effect was more pronounced in soils of large macroporosity. Preliminary results indicate that the model is insensitive to geometrical properties of macropores

  7. A criterion for the onset of slugging in horizontal stratified air-water countercurrent flow

    International Nuclear Information System (INIS)

    Chun, Moon-Hyun; Lee, Byung-Ryung; Kim, Yang-Seok

    1995-01-01

    This paper presents an experimental and theoretical investigation of wave height and transition criterion from wavy to slug flow in horizontal air-water countercurrent stratified flow conditions. A theoretical formula for the wave height in a stratified wavy flow regime has been developed using the concept of total energy balance over a wave crest to consider the shear stress acting on the interface of two fluids. From the limiting condition of the formula for the wave height, a necessary criterion for transition from a stratified wavy flow to a slug flow has been derived. A series of experiments have been conducted changing the non-dimensional water depth and the flow rates of air in a horizontal pipe and a duct. Comparisons between the measured data and the predictions of the present theory show that the agreement is within ±8%

  8. A criterion for the onset of slugging in horizontal stratified air-water countercurrent flow

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Moon-Hyun; Lee, Byung-Ryung; Kim, Yang-Seok [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)] [and others

    1995-09-01

    This paper presents an experimental and theoretical investigation of wave height and transition criterion from wavy to slug flow in horizontal air-water countercurrent stratified flow conditions. A theoretical formula for the wave height in a stratified wavy flow regime has been developed using the concept of total energy balance over a wave crest to consider the shear stress acting on the interface of two fluids. From the limiting condition of the formula for the wave height, a necessary criterion for transition from a stratified wavy flow to a slug flow has been derived. A series of experiments have been conducted changing the non-dimensional water depth and the flow rates of air in a horizontal pipe and a duct. Comparisons between the measured data and the predictions of the present theory show that the agreement is within {plus_minus}8%.

  9. Water flow and solute transport through fractured rock

    International Nuclear Information System (INIS)

    Bolt, J.E.; Bourke, P.J.; Pascoe, D.M.; Watkins, V.M.B.; Kingdon, R.D.

    1990-09-01

    In densely fractured slate at the Nirex research site in Cornwall, the positions, orientations and hydraulic conductivities of the 380 fractures intersecting a drill hole between 9 and 50 m depth have been individually measured. These data have been used: to determine the dimensions of statistically representative volumes of the network of fractures and to predict, using discrete flow path modelling and the NAPSAC code, the total flows into the fractures when large numbers are simultaneously pressurised along various lengths of the hole. Corresponding measurements, which validated the NAPSAC code to factor of two accuracy for the Cornish site, are reported. Possibilities accounting for this factor are noted for experimental investigation, and continuing, more extensive, inter hole flow and transport measurements are outlined. The application of this experimental and theoretical approach for calculating radionuclide transport in less densely fractured rock suitable for waste disposal is discussed. (Author)

  10. Raman scattering temperature measurements for water vapor in nonequilibrium dispersed two-phase flow

    International Nuclear Information System (INIS)

    Anastasia, C.M.; Neti, S.; Smith, W.R.; Chen, J.C.

    1982-09-01

    The objective of this investigation was to determine the feasibility of using Raman scattering as a nonintrusive technique to measure vapor temperatures in dispersed two-phase flow. The Raman system developed for this investigation is described, including alignment of optics and optimization of the photodetector for photon pulse counting. Experimentally obtained Raman spectra are presented for the following single- and two-phase samples: liquid water, atmospheric nitrogen, superheated steam, nitrogen and water droplets in a high void fraction air/water mist, and superheated water vapor in nonequilibrium dispersed flow

  11. A completely passive continuous flow solar water purification system

    Energy Technology Data Exchange (ETDEWEB)

    Duff, William S.; Hodgson, David A. [Dept. of Mechanical Enginnering, Colorado State Univ., Fort Collins, CO (United States)

    2008-07-01

    Water-borne pathogens in developing countries cause several billion cases of disease and up to 10 million deaths each year, at least half of which are children. Solar water pasteurization is a potentially cost-effective, robust and reliable solution to these problems. A completely passively controlled solar water pasteurization system with a total collector area of 0.45 m{sup 2} has been constructed. The system most recently tested produced 337 litres per m{sup 2} of collector area of treated water on a sunny day. We developed our completely passive density-driven solar water pasteurization system over a five year span so that it now achieves reliable control for all possible variations in solar conditions. We have also substantially increased its daily pure water production efficiency over the same period. We will discuss the performance of our water purification system and provide an analyses that demonstrates that the system insures safe purified water production at all times. (orig.)

  12. Malignant human cell transformation of Marcellus Shale gas drilling flow back water

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Yixin [Department of Epidemiology, Shanghai Jiaotong University School of Public Health (China); Department of Environmental Medicine, New York University School of Medicine, Tuxedo, NY 10987 (United States); Chen, Tingting [School of Material Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Shen, Steven S. [Biochemistry and Molecular Pharmaceutical, New York University School of Medicine (United States); Niu, Yingmei; DesMarais, Thomas L.; Linn, Reka; Saunders, Eric; Fan, Zhihua [Department of Environmental Medicine, New York University School of Medicine, Tuxedo, NY 10987 (United States); Lioy, Paul [Robert Wood Johnson Medical School Rutgers, The State University of New Jersey, Piscataway, NJ 08854 (United States); Kluz, Thomas; Chen, Lung-Chi [Department of Environmental Medicine, New York University School of Medicine, Tuxedo, NY 10987 (United States); Wu, Zhuangchun, E-mail: wuzhuangchun@mail.njust.edu.cn [College of Science, Donghua University, Shanghai 201620 (China); Costa, Max, E-mail: max.costa@nyumc.org [Department of Environmental Medicine, New York University School of Medicine, Tuxedo, NY 10987 (United States)

    2015-10-01

    The rapid development of high-volume horizontal hydraulic fracturing for mining natural gas from shale has posed potential impacts on human health and biodiversity. The produced flow back waters after hydraulic stimulation are known to carry high levels of saline and total dissolved solids. To understand the toxicity and potential carcinogenic effects of these wastewaters, flow back waters from five Marcellus hydraulic fracturing oil and gas wells were analyzed. The physicochemical nature of these samples was analyzed by inductively coupled plasma mass spectrometry and scanning electron microscopy/energy dispersive X-ray spectroscopy. A cytotoxicity study using colony formation as the endpoint was carried out to define the LC{sub 50} values of test samples using human bronchial epithelial cells (BEAS-2B). The BEAS-2B cell transformation assay was employed to assess the carcinogenic potential of the samples. Barium and strontium were among the most abundant metals in these samples and the same metals were found to be elevated in BEAS-2B cells after long-term treatment. BEAS-2B cells treated for 6 weeks with flow back waters produced colony formation in soft agar that was concentration dependent. In addition, flow back water-transformed BEAS-2B cells show better migration capability when compared to control cells. This study provides information needed to assess the potential health impact of post-hydraulic fracturing flow back waters from Marcellus Shale natural gas mining. - Highlights: • This is the first report of potential cytotoxicity and transforming activity of Marcellus shale gas mining flow back to mammalian cells. • Barium and Strontium were elevated in flow back water exposed cells. • Flow back water malignantly transformed cells and formed tumor in athymic nude mice. • Flow back transformed cells exhibited altered transcriptome with dysregulated cell migration pathway and adherent junction pathway.

  13. Malignant human cell transformation of Marcellus Shale gas drilling flow back water

    International Nuclear Information System (INIS)

    Yao, Yixin; Chen, Tingting; Shen, Steven S.; Niu, Yingmei; DesMarais, Thomas L.; Linn, Reka; Saunders, Eric; Fan, Zhihua; Lioy, Paul; Kluz, Thomas; Chen, Lung-Chi; Wu, Zhuangchun; Costa, Max

    2015-01-01

    The rapid development of high-volume horizontal hydraulic fracturing for mining natural gas from shale has posed potential impacts on human health and biodiversity. The produced flow back waters after hydraulic stimulation are known to carry high levels of saline and total dissolved solids. To understand the toxicity and potential carcinogenic effects of these wastewaters, flow back waters from five Marcellus hydraulic fracturing oil and gas wells were analyzed. The physicochemical nature of these samples was analyzed by inductively coupled plasma mass spectrometry and scanning electron microscopy/energy dispersive X-ray spectroscopy. A cytotoxicity study using colony formation as the endpoint was carried out to define the LC 50 values of test samples using human bronchial epithelial cells (BEAS-2B). The BEAS-2B cell transformation assay was employed to assess the carcinogenic potential of the samples. Barium and strontium were among the most abundant metals in these samples and the same metals were found to be elevated in BEAS-2B cells after long-term treatment. BEAS-2B cells treated for 6 weeks with flow back waters produced colony formation in soft agar that was concentration dependent. In addition, flow back water-transformed BEAS-2B cells show better migration capability when compared to control cells. This study provides information needed to assess the potential health impact of post-hydraulic fracturing flow back waters from Marcellus Shale natural gas mining. - Highlights: • This is the first report of potential cytotoxicity and transforming activity of Marcellus shale gas mining flow back to mammalian cells. • Barium and Strontium were elevated in flow back water exposed cells. • Flow back water malignantly transformed cells and formed tumor in athymic nude mice. • Flow back transformed cells exhibited altered transcriptome with dysregulated cell migration pathway and adherent junction pathway.

  14. Three-dimensional flow measurement of a water flow in a sphere-packed pipe by digital holographic PTV

    Energy Technology Data Exchange (ETDEWEB)

    Satake, Shin-ichi, E-mail: satake@te.noda.tus.ac.jp [Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585 (Japan); Aoyagi, Yusuke [Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585 (Japan); Unno, Noriyuki [Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585 (Japan); Japan Society for the Promotion of Science, 5-3-1 Kojimachi, Chiyoda-ku, Tokyo 102-0083 (Japan); Yuki, Kazuhisa [Department of Mechanical Engineering, Tokyo University of Science, Yamaguchi, Daigaku-dori 1-1-1, Sanyo-Onoda, Yamaguchi 756-0884 (Japan); Seki, Yohji; Enoeda, Mikio [Japan Atomic Energy Agency, Blanket Technology Group, 801-1 Mukoyama, Naka-shi, Ibaraki-ken 311-0193 (Japan)

    2015-10-15

    A water cooled ceramic breeder for ITER and DEMO of a nuclear fusion reactor plays a significant role in the design of a blanket module. Pebbles of a ceramic tritium breeder are packed in a container of the blanket. Investigation of the flow behavior is necessary in an actual environment of a facility where pressure drop takes place under a complex flow such as in case of the container for the pebble bed. For the development of a facility, it is necessary to be able to monitor fluid motion of a basic flow such as a sphere-packed pipe (SPP). In the present study, to discern the complex flow structures in SPP, digital holographic PTV visualization is carried out by a refractive index-matching method using a water employed as a working fluid. The water is chosen to be able to adjust its refractive index to match to that of the MEXFLON pebble with an index of 1.33. Hologram fringe images of particles behind the spheres can be observed, and the particles’ positions can be reconstructed by a digital hologram. Consequently, 3-D velocity-fields around the spheres are obtained by the reconstructed particles’ positions. The velocity between pebbles is found to be convergence and divergence regions in the SPP.

  15. Air-water upward flow in prismatic channel of rectangular base

    International Nuclear Information System (INIS)

    Carvalho Tofani, P. de.

    1984-01-01

    Experiments had carried out to investigate the two-phase upward air-water flow structure, in a rectangular test section, by using independent measuring techniques, which comprise direct viewing and photography, electrical probes and gamma-ray attenuation. Flow pattern maps and correlations for flow pattern transitions, void fraction profiles, liquid film thickness and superficial average void fraction are proposed and compared to available data. (Author) [pt

  16. A method and programme (BREACH) for predicting the flow distribution in water cooled reactor cores

    International Nuclear Information System (INIS)

    Randles, J.; Roberts, H.A.

    1961-03-01

    The method presented here of evaluating the flow rate in individual reactor channels may be applied to any type of water cooled reactor in which boiling occurs The flow distribution is calculated with the aid of a MERCURY autocode programme, BREACH, which is described in detail. This programme computes the steady state longitudinal void distribution and pressure drop in a single channel on the basis of the homogeneous model of two phase flow. (author)

  17. A method and programme (BREACH) for predicting the flow distribution in water cooled reactor cores

    Energy Technology Data Exchange (ETDEWEB)

    Randles, J; Roberts, H A [Technical Assessments and Services Division, Atomic Energy Establishment, Winfrith, Dorchester, Dorset (United Kingdom)

    1961-03-15

    The method presented here of evaluating the flow rate in individual reactor channels may be applied to any type of water cooled reactor in which boiling occurs The flow distribution is calculated with the aid of a MERCURY autocode programme, BREACH, which is described in detail. This programme computes the steady state longitudinal void distribution and pressure drop in a single channel on the basis of the homogeneous model of two phase flow. (author)

  18. Heat flow and subsurface temperature as evidence for basin-scale ground-water flow, North Slope of Alaska

    Science.gov (United States)

    Deming, D.; Sass, J.H.; Lachenbruch, A.H.; De Rito, R. F.

    1992-01-01

    Several high-resolution temperature logs were made in each of 21 drillholes and a total of 601 thermal conductivity measurements were made on drill cuttings and cores. Near-surface heat flow (??20%) is inversely correlated with elevation and ranges from a low of 27 mW/m2 in the foothills of the Brooks Range in the south, to a high of 90 mW/m2 near the north coast. Subsurface temperatures and thermal gradients estimated from corrected BHTs are similarly much higher on the coastal plain than in the foothills province to the south. Significant east-west variation in heat flow and subsurface temperature is also observed; higher heat flow and temperature coincide with higher basement topography. The observed thermal pattern is consistent with forced convection by a topographically driven ground-water flow system. Average ground-water (Darcy) velocity in the postulated flow system is estimated to be of the order of 0.1 m/yr; the effective basin-scale permeability is estimated to be of the order of 10-14 m2. -from Authors

  19. Coupled heat and water flow dynamics in dry soils : application to a multilayer waste cover

    OpenAIRE

    Gran Esforzado, Meritxell

    2015-01-01

    Unsaturated flow plays an important role in numerous environmental phenomena. It is complex in arid regions, where liquid water fluxes are small and vapor fluxes become relevant, so that heat, water and solute mass transport are needed to understand evaporation. This thesis aims at gaining insight evaporation and vapor flow mechanisms and the relevance of matric potential, temperature and osmotic gradients. These issues are especially relevant for soil salinization, whose mechanisms are po...

  20. Measurement of thickness of thin water film in two-phase flow by capacitance method

    International Nuclear Information System (INIS)

    Sun, R.K.; Kolbe, W.F.; Leskovar, B.; Turko, B.

    1981-09-01

    A technique has been developed for measuring water film thickness in a two-phase annular flow system by the capacitance method. An experimental model of the flow system with two types of electrodes mounted on the inner wall of a cylindrical tube has been constructed and evaluated. The apparatus and its ability to observe fluctuations and wave motions of the water film passing over the electrodes is described in some detail

  1. Hydrogeologic setting and ground water flow beneath a section of Indian River Bay, Delaware

    Science.gov (United States)

    Krantz, David E.; Manheim, Frank T.; Bratton, John F.; Phelan, Daniel J.

    2004-01-01

    The small bays along the Atlantic coast of the Delmarva Peninsula (Delaware, Maryland, and Virginia) are a valuable natural resource, and an asset for commerce and recreation. These coastal bays also are vulnerable to eutrophication from the input of excess nutrients derived from agriculture and other human activities in the watersheds. Ground water discharge may be an appreciable source of fresh water and a transport pathway for nutrients entering the bays. This paper presents results from an investigation of the physical properties of the surficial aquifer and the processes associated with ground water flow beneath Indian River Bay, Delaware. A key aspect of the project was the deployment of a new technology, streaming horizontal resistivity, to map the subsurface distribution of fresh and saline ground water beneath the bay. The resistivity profiles showed complex patterns of ground water flow, modes of mixing, and submarine ground water discharge. Cores, gamma and electromagnetic-induction logs, and in situ ground water samples collected during a coring operation in Indian River Bay verified the interpretation of the resistivity profiles. The shore-parallel resistivity lines show subsurface zones of fresh ground water alternating with zones dominated by the flow of salt water from the estuary down into the aquifer. Advective flow produces plumes of fresh ground water 400 to 600 m wide and 20 m thick that may extend more than 1 km beneath the estuary. Zones of dispersive mixing between fresh and saline ground water develop on the upper, lower, and lateral boundaries of the the plume. the plumes generally underlie small incised valleys that can be traced landward to stream draining the upland. The incised valleys are filled with 1 to 2 m of silt and peat that act as a semiconfining layer to restrict the downward flow of salt water from the estuary. Active circulation of both the fresh and saline ground water masses beneath the bay is inferred from the geophysical

  2. Modeling water droplet condensation and evaporation in DNS of turbulent channel flow

    NARCIS (Netherlands)

    Russo, E.; Kuerten, J.G.M.; Geld, van der C.W.M.; Geurts, B.J.

    2011-01-01

    In this paper a point particle model for two-way coupling in water droplet-laden incompressible turbulent flow of air is proposed. The model is based on conservation laws and semi-empirical correlations. It has been implemented and tested in a DNS code based for turbulent channel flow with an

  3. Modeling water droplet condensation and evaporation in DNS of turbulent channel flow

    NARCIS (Netherlands)

    Russo, E; Kuerten, Johannes G.M.; van der Geld, C.W.M.; Geurts, Bernardus J.

    In this paper a point particle model for two-way coupling in water droplet-laden incompressible turbulent flow of air is proposed. The model is based on conservation laws and semi-empirical correlations. It has been implemented and tested in a DNS code based for turbulent channel flow with an

  4. A double parameters measurement of steam-water two-phase flow with single orifice

    International Nuclear Information System (INIS)

    Zhong Shuoping; Tong Yunxian; Yu Meiying

    1992-08-01

    A double parameters measurement of steam-water two-phase flow with single orifice is described. An on-line measurement device based on micro-computer has been developed. The measured r.m.s error of steam quality is less than 6.5% and the measured relative r.m.s. error of mass flow rate is less than 9%

  5. Energy efficiency of selected OECD countries: A slacks based model with undesirable outputs

    International Nuclear Information System (INIS)

    Apergis, Nicholas; Aye, Goodness C.; Barros, Carlos Pestana; Gupta, Rangan; Wanke, Peter

    2015-01-01

    This paper presents an efficiency assessment of selected OECD countries using a Slacks Based Model with undesirable or bad outputs (SBM-Undesirable). In this research, SBM-Undesirable is used first in a two-stage approach to assess the relative efficiency of OECD countries using the most frequent indicators adopted by the literature on energy efficiency. Besides, in the second stage, GLMM–MCMC methods are combined with SBM-Undesirable results as part of an attempt to produce a model for energy performance with effective predictive ability. The results reveal different impacts of contextual variables, such as economic blocks and capital–labor ratio, on energy efficiency levels. - Highlights: • We analyze the energy efficiency of selected OECD countries. • SBM-Undesirable and MCMC–GLMM are combined for this purpose. • Find that efficiency levels are high but declining over time. • Analysis with contextual variables shows varying efficiency levels across groups. • Capital-intensive countries are more energy efficient than labor-intensive countries.

  6. Slug flow transitions in horizontal gas/liquid two-phase flows. Dependence on channel height and system pressure for air/water and steam/water two-phase flows

    International Nuclear Information System (INIS)

    Nakamura, Hideo

    1996-05-01

    The slug flow transitions and related phenomena for horizontal two-phase flows were studied for a better prediction of two-phase flows that typically appear during the reactor loss-of-coolant accidents (LOCAs). For better representation of the flow conditions experimentally, two large-scaled facility: TPTF for high-pressure steam/water two-phase flows and large duct test facility for air/water two-phase flows, were used. The visual observation of the flow using a video-probe was performed in the TPTF experiments for good understanding of the phenomena. The currently-used models and correlations based mostly on the small-scale low-pressure experiments were reviewed and improved based on these experimental results. The modified Taitel-Dukler model for prediction of transition into slug flow from wavy flow and the modified Steen-Wallis correlation for prediction of onset of liquid entrainment from the interfacial waves were obtained. An empirical correlation for the gas-liquid interfacial friction factor was obtained further for prediction of liquid levels at wavy flow. The region of slug flow regime that is generally under influences of the channel height and system pressure was predicted well when these models and correlations were applied together. (author). 90 refs

  7. Design configurations affecting flow pattern and solids accumulation in horizontal free water and subsurface flow constructed wetlands.

    Science.gov (United States)

    Pedescoll, A; Sidrach-Cardona, R; Sánchez, J C; Carretero, J; Garfi, M; Bécares, E

    2013-03-01

    The aim of this study was to evaluate the effect of different horizontal constructed wetland (CW) design parameters on solids distribution, loss of hydraulic conductivity over time and hydraulic behaviour, in order to assess clogging processes in wetlands. For this purpose, an experimental plant with eight CWs was built at mesocosm scale. Each CW presented a different design characteristic, and the most common CW configurations were all represented: free water surface flow (FWS) with different effluent pipe locations, FWS with floating macrophytes and subsurface flow (SSF), and the presence of plants and specific species (Typha angustifolia and Phragmites australis) was also considered. The loss of the hydraulic conductivity of gravel was greatly influenced by the presence of plants and organic load (representing a loss of 20% and c.a. 10% in planted wetlands and an overloaded system, respectively). Cattail seems to have a greater effect on the development of clogging since its below-ground biomass weighed twice as much as that of common reed. Hydraulic behaviour was greatly influenced by the presence of a gravel matrix and the outlet pipe position. In strict SSF CW, the water was forced to cross the gravel and tended to flow diagonally from the top inlet to the bottom outlet (where the inlet and outlet pipes were located). However, when FWS was considered, water preferentially flowed above the gravel, thus losing half the effective volume of the system. Only the presence of plants seemed to help the water flow partially within the gravel matrix. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Climate influences on Vaal River flow | Jury | Water SA

    African Journals Online (AJOL)

    A study of climatic influences on Vaal River discharge, near Johannesburg, South Africa, finds that peak summer flows in the period 1979–2014 coincide with ocean–atmosphere interaction in the east Atlantic. The analysis has three parts: interannual influences by correlation of summer discharge with climate fields, ...

  9. Mechanical effects of water flow on fish eggs and larvae

    International Nuclear Information System (INIS)

    Ulanowicz, R.E.

    1975-01-01

    The impact of mechanical stresses on ichthyoplankton entrained in power plant cooling systems has long been considered negligible. Arguments and evidence exist, however, to show that such a supposition is not universally true, especially in nuclear power plants. The mechanisms of mechanical damage can be detailed in terms of pressure change, acceleration, and shear stress within the fluid flow field. (U.S.)

  10. Heterogeneity of water flow in grassland soil during irrigation experiment

    Czech Academy of Sciences Publication Activity Database

    Lichner, Ľ.; Dušek, J.; Tesař, Miroslav; Czachor, H.; Mészároš, I.

    2014-01-01

    Roč. 69, č. 11 (2014), s. 1555-1561 ISSN 0006-3088 R&D Projects: GA TA ČR(CZ) TA0201451 Grant - others:ERDF ITMS26240120004 Institutional support: RVO:67985874 Keywords : degree of preferential flow * effective cross section * infiltration experiment * radioactive tracer technique * sandy soil Subject RIV: DA - Hydrology ; Limnology Impact factor: 0.827, year: 2014

  11. two - dimensional mathematical model of water flow in open

    African Journals Online (AJOL)

    ES Obe

    1996-09-01

    Sep 1, 1996 ... ... one or more navigation locks or of a hydro electric plant. In a case like this it is often necessary to consider how, for instance, the handling of the weir gates influences the flow upstream of the hydropower plant or, on the contrary, what effect the operation of the wajerwork would have on the distribution of.

  12. Low-Flow Water Study for the Missouri River.

    Science.gov (United States)

    2008-08-01

    The (MoDOT) retained TranSystems to identify and review low-flow industry : trends, equipment and strategies used in inland navigation settings throughout the United States and worldwide which : may be transferable to the Missouri River and which cou...

  13. Ground-water flow and ground- and surface-water interaction at the Weldon Spring quarry, St. Charles County, Missouri

    International Nuclear Information System (INIS)

    Imes, J.L.; Kleeschulte, M.J.

    1997-01-01

    Ground-water-level measurements to support remedial actions were made in 37 piezometers and 19 monitoring wells during a 19-month period to assess the potential for ground-water flow from an abandoned quarry to the nearby St. Charles County well field, which withdraws water from the base of the alluvial aquifer. From 1957 to 1966, low-level radioactive waste products from the Weldon Spring chemical plant were placed in the quarry a few hundred feet north of the Missouri River alluvial plain. Uranium-based contaminants subsequently were detected in alluvial ground water south of the quarry. During all but flood conditions, lateral ground-water flow in the bedrock from the quarry, as interpreted from water-table maps, generally is southwest toward Little Femme Osage Creek or south into the alluvial aquifer. After entering the alluvial aquifer, the ground water flows southeast to east toward a ground-water depression presumably produced by pumping at the St. Charles County well field. The depression position varies depending on the Missouri River stage and probably the number and location of active wells in the St. Charles County well field

  14. Hydrogeology, simulated ground-water flow, and ground-water quality, Wright-Patterson Air Force Base, Ohio

    Science.gov (United States)

    Dumouchelle, D.H.; Schalk, C.W.; Rowe, G.L.; De Roche, J.T.

    1993-01-01

    Ground water is the primary source of water in the Wright-Patterson Air Force Base area. The aquifer consists of glacial sands and gravels that fill a buried bedrock-valley system. Consolidated rocks in the area consist of poorly permeable Ordovician shale of the Richmondian stage, in the upland areas, the Brassfield Limestone of Silurian age. The valleys are filled with glacial sediments of Wisconsinan age consisting of clay-rich tills and coarse-grained outwash deposits. Estimates of hydraulic conductivity of the shales based on results of displacement/recovery tests range from 0.0016 to 12 feet per day; estimates for the glacial sediments range from less than 1 foot per day to more than 1,000 feet per day. Ground water flow from the uplands towards the valleys and the major rivers in the region, the Great Miami and the Mad Rivers. Hydraulic-head data indicate that ground water flows between the bedrock and unconsolidated deposits. Data from a gain/loss study of the Mad River System and hydrographs from nearby wells reveal that the reach of the river next to Wright-Patterson Air Force Base is a ground-water discharge area. A steady-state, three-dimensional ground-water-flow model was developed to simulate ground-water flow in the region. The model contains three layers and encompasses about 100 square miles centered on Wright-Patterson Air Force Base. Ground water enters the modeled area primarily by river leakage and underflow at the model boundary. Ground water exits the modeled area primarily by flow through the valleys at the model boundaries and through production wells. A model sensitivity analysis involving systematic changes in values of hydrologic parameters in the model indicates that the model is most sensitive to decreases in riverbed conductance and vertical conductance between the upper two layers. The analysis also indicates that the contribution of water to the buried-valley aquifer from the bedrock that forms the valley walls is about 2 to 4

  15. [Stem sap flow and water consumption of Tamarix ramosissima in hinterland of Taklimakan Desert].

    Science.gov (United States)

    Xu, Hao; Zhang, Xi-Ming; Yan, Hai-Long; Yao, Shi-Jun

    2007-04-01

    From April to November 2005, the stem sap flow and water consumption of Tamarix ramosissima in the hinterland of Taklimakan Desert was measured by Flow-32 System. The results showed that, in the extremely arid hinterland of Taklimakan Desert and under enough water supply, the average daily water consumption of T. ramosissima with a stem diameter of 3.5 cm and 2.0 cm was 6.322 kg and 1.179 kg, respectively in one growth season. The stem sap flow of T. ramosissima presented a single-peaked curve, with an obvious day and night variation rhythm and fluctuated with environment factors. Under enough water supply, the environmenal factors such as total radiation, wind speed and air temperature were the main factors affecting the stem sap flow, and the dynamics of stem sap flow could be predicted by the liner regression model based on total radiation and wind speed. Because of the extremely arid environment and enough water supply, T. ramosissima had a relatively higher stem sap flow rate and a great water consumption.

  16. Effect of interfacial layer on water flow in nanochannels: Lattice Boltzmann simulations

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Yakang [State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Qingdao, Shandong 266580 (China); College of Science, China University of Petroleum, Qingdao 266580, Shandong (China); Liu, Xuefeng, E-mail: liuxf@upc.edu.cn [College of Science, China University of Petroleum, Qingdao 266580, Shandong (China); Liu, Zilong [College of Science, China University of Petroleum, Qingdao 266580, Shandong (China); Lu, Shuangfang [Institute of Unconventional Oil & Gas and New Energy, China University of Petroleum, Qingdao 266580, Shandong (China); Xue, Qingzhong, E-mail: xueqingzhong@tsinghua.org.cn [State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Qingdao, Shandong 266580 (China); College of Science, China University of Petroleum, Qingdao 266580, Shandong (China); National Production Equipment Research Center, Dongying 257064, Shandong (China)

    2016-04-15

    A novel interfacial model was proposed to understand water flow mechanism in nanochannels. Based on our pore-throat nanochannel model, the effect of interfacial layer on water flow in nanochannels was quantitatively studied using Lattice Boltzmann method (LBM). It is found that both the permeability of nanochannel and water velocity in the nanochannel dramatically decrease with increasing the thickness of interfacial layer. The permeability of nanochannel with pore radius of 10 nm decreases by about three orders of magnitude when the thickness of interfacial layer is changed from 0 nm to 3 nm gradually. Furthermore, it has been demonstrated that the cross-section shape has a great effect on the water flow inside nanochannel and the effect of interfacial layer on the permeability of nanochannel has a close relationship with cross-section shape when the pore size is smaller than 12 nm. Besides, both pore-throat ratio and throat length can greatly affect water flow in nanochannels, and the influence of interfacial layer on water flow in nanochannels becomes more evident with increasing pore-throat ratio and throat length. Our theoretical results provide a simple and effective method to study the flow phenomena in nano-porous media, particularly to quantitatively study the interfacial layer effect in nano-porous media.

  17. Water-Level Data Analysis for the Saturated Zone Site-Scale Flow and Transport Model

    International Nuclear Information System (INIS)

    K. Rehfeldt

    2004-01-01

    This report is an updated analysis of water-level data performed to provide the ''Saturated Zone Site-Scale Flow Model'' (BSC 2004 [DIRS 170037]) (referred to as the saturated zone (SZ) site-scale flow model or site-scale SZ flow model in this report) with the configuration of the potentiometric surface, target water-level data, and hydraulic gradients for calibration of groundwater flow models. This report also contains an expanded discussion of uncertainty in the potentiometric-surface map. The analysis of the potentiometric data presented in Revision 00 of this report (USGS 2001 [DIRS 154625]) provides the configuration of the potentiometric surface, target heads, and hydraulic gradients for the calibration of the SZ site-scale flow model (BSC 2004 [DIRS 170037]). Revision 01 of this report (USGS 2004 [DIRS 168473]) used updated water-level data for selected wells through the year 2000 as the basis for estimating water-level altitudes and the potentiometric surface in the SZ site-scale flow and transport model domain based on an alternative interpretation of perched water conditions. That revision developed computer files containing: Water-level data within the model area (DTN: GS010908312332.002); A table of known vertical head differences (DTN: GS010908312332.003); and A potentiometric-surface map (DTN: GS010608312332.001) using an alternative concept from that presented by USGS (2001 [DIRS 154625]) for the area north of Yucca Mountain. The updated water-level data presented in USGS (2004 [DIRS 168473]) include data obtained from the Nye County Early Warning Drilling Program (EWDP) Phases I and II and data from Borehole USW WT-24. This document is based on Revision 01 (USGS 2004 [DIRS 168473]) and expands the discussion of uncertainty in the potentiometric-surface map. This uncertainty assessment includes an analysis of the impact of more recent water-level data and the impact of adding data from the EWDP Phases III and IV wells. In addition to being utilized

  18. Water-Level Data Analysis for the Saturated Zone Site-Scale Flow and Transport Model

    Energy Technology Data Exchange (ETDEWEB)

    K. Rehfeldt

    2004-10-08

    This report is an updated analysis of water-level data performed to provide the ''Saturated Zone Site-Scale Flow Model'' (BSC 2004 [DIRS 170037]) (referred to as the saturated zone (SZ) site-scale flow model or site-scale SZ flow model in this report) with the configuration of the potentiometric surface, target water-level data, and hydraulic gradients for calibration of groundwater flow models. This report also contains an expanded discussion of uncertainty in the potentiometric-surface map. The analysis of the potentiometric data presented in Revision 00 of this report (USGS 2001 [DIRS 154625]) provides the configuration of the potentiometric surface, target heads, and hydraulic gradients for the calibration of the SZ site-scale flow model (BSC 2004 [DIRS 170037]). Revision 01 of this report (USGS 2004 [DIRS 168473]) used updated water-level data for selected wells through the year 2000 as the basis for estimating water-level altitudes and the potentiometric surface in the SZ site-scale flow and transport model domain based on an alternative interpretation of perched water conditions. That revision developed computer files containing: Water-level data within the model area (DTN: GS010908312332.002); A table of known vertical head differences (DTN: GS010908312332.003); and A potentiometric-surface map (DTN: GS010608312332.001) using an alternative concept from that presented by USGS (2001 [DIRS 154625]) for the area north of Yucca Mountain. The updated water-level data presented in USGS (2004 [DIRS 168473]) include data obtained from the Nye County Early Warning Drilling Program (EWDP) Phases I and II and data from Borehole USW WT-24. This document is based on Revision 01 (USGS 2004 [DIRS 168473]) and expands the discussion of uncertainty in the potentiometric-surface map. This uncertainty assessment includes an analysis of the impact of more recent water-level data and the impact of adding data from the EWDP Phases III and IV wells. In

  19. Investigation on the liquid water droplet instability in a simulated flow channel of PEM fuel cell

    International Nuclear Information System (INIS)

    Ha, Tae Hun; Kim, Bok Yung; Kim, Han Sang; Min, Kyoung Doug

    2008-01-01

    To investigate the characteristics of water droplets on the gas diffusion layer from both top-view and side-view of the flow channel, a rig test apparatus was designed and fabricated with prism attached plate. This experimental device was used to simulate the growth of a single liquid water droplet and its transport process with various air flow velocity and channel height. Not only dry condition but also fully humidified condition was also simulated by using a water absorbing sponge. The detachment height of the water droplet with dry and wet conditions was measured and analyzed. It was found that the droplet tends towards becoming unstable by decreased channel height, increased flow velocity or making a gas diffusion layer (GDL) dryer. Also, peculiar behavior of the water droplet in the channel was presented like attachment to hydrophilic wall or sudden breaking of droplet in case of fully hydrated condition. The simplified force balance model matches with experimental data as well

  20. Prediction of unsaturated flow and water backfill during infiltration in layered soils

    Science.gov (United States)

    Cui, Guotao; Zhu, Jianting

    2018-02-01

    We develop a new analytical infiltration model to determine water flow dynamics around layer interfaces during infiltration process in layered soils. The model mainly involves the analytical solutions to quadratic equations to determine the flux rates around the interfaces. Active water content profile behind the wetting front is developed based on the solution of steady state flow to dynamically update active parameters in sharp wetting front infiltration equations and to predict unsaturated flow in coarse layers before the front reaches an impeding fine layer. The effect of water backfill to saturate the coarse layers after the wetting front encounters the impeding fine layer is analytically expressed based on the active water content profiles. Comparison to the numerical solutions of the Richards equation shows that the new model can well capture water dynamics in relation to the arrangement of soil layers. The steady state active water content profile can be used to predict the saturation state of all layers when the wetting front first passes through these layers during the unsteady infiltration process. Water backfill effect may occur when the unsaturated wetting front encounters a fine layer underlying a coarse layer. Sensitivity analysis shows that saturated hydraulic conductivity is the parameter dictating the occurrence of unsaturated flow and water backfill and can be used to represent the coarseness of soil layers. Water backfill effect occurs in coarse layers between upper and lower fine layers when the lower layer is not significantly coarser than the upper layer.

  1. Novel flow-through bioremediation system for removing nitrate from nursery discharge water.

    Science.gov (United States)

    Chris Wilson, P; Albano, Joseph P

    2013-11-30

    Nitrate losses in surface runoff water from nursery production areas can be significant. This study evaluated the potential use of microbial-based (denitrification), flow-through bioreactors for their nitrate-remediation ability. Duplicate bioreactor systems were constructed at a local foliage plant nursery. Each bioreactor system consisted of four 242 L tanks with connections alternating between bottom and top. Each tank was filled with approximately 113 L of Kaldness media to provide surface area for attachment of native microflora. Molasses was supplied as a carbon source for denitrification and water flow rates through the systems ranged from 5 to 18 L min(-1) during tests. Automatic water samplers were used to collect composite samples every 15 min from both the inflow and the exit flow water. Results indicate consistent removal of 80-100% of the nitrate flowing into the systems. Accumulation of ammoniacal and nitrite nitrogen did not occur, indicating that the nitrate-nitrogen was removed from the water, and not simply transformed into another water-soluble species. Occasions where removal rates were less than 80% were usually traced to faulty delivery of the carbon source. Results indicate that modular microbial-based bioremediation systems may be a useful tool for helping water managers meet stringent nitrogen water quality regulations, especially at nurseries with limited space for expansion of water retention facilities. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Flow characteristics of centrifugal gas-liquid separator. Investigation with air-water two-phase flow experiment

    International Nuclear Information System (INIS)

    Yoneda, Kimitoshi; Inada, Fumio

    2004-01-01

    Air-water two-phase flow experiment was conducted to examine the basic flow characteristics of a centrifugal gas-liquid separator. Vertical transparent test section, which is 4 m in height, was used to imitate the scale of a BWR separator. Flow rate conditions of gas and liquid were fixed at 0.1 m 3 /s and 0.033 m 3 /s, respectively. Radial distributions of two-phase flow characteristics, such as void fraction, gas velocity and bubble chord length, were measured by traversing dual optical void probes in the test section, horizontally. The flow in the standpipe reached to quasi-developed state within the height-to-diameter aspect ratio H/D=10, which in turn can mean the maximum value for an ideal height design of a standpipe. The liquid film in the barrel showed a maximum thickness at 0.5 to 1 m in height from the swirler exit, which was a common result for three different standpipe length conditions, qualitatively and quantitatively. The empirical database obtained in this study would contribute practically to the validation of numerical analyses for an actual separator in a plant, and would also be academically useful for further investigations of two-phase flow in large-diameter pipes. (author)

  3. The effects of viscosity, surface tension, and flow rate on gasoil-water flow pattern in microchannels

    Energy Technology Data Exchange (ETDEWEB)

    Boogar, Rahman Sadeghi; Gheshlaghi, Reza; Mahdavi, Mahmood Akhavan [Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of)

    2013-01-15

    A microchannel was fabricated with glass tubes to investigate the effect of viscosity, surface tension, and flow rate on the liquid-liquid two-phase flow regime. Water and gasoil were selected as aqueous and organic working fluids, respectively. The two fluids were injected into the microchannel and created either slug or parallel profile depending on the applied conditions. The range of Reynolds and capillary numbers was chosen in such a way that neither inertia nor interfacial tension forces were negligible. Xanthan gum was used to increase viscosity and Triton X-100 (TX-100) and Sodium Dodecyl Sulfate (SDS) were used to reduce the interfacial tension. The results demonstrated that higher value of viscosity and flow rate increased interfacial area, but slug flow regime remained unchanged. The two surfactants showed different effects on the flow regime and interfacial area. Addition of TX-100 did not change the slug flow but decreased the interfacial area. In contrast, addition of SDS increased interfacial area by decreasing the slug’s length in the low concentrations and by switching from slug to parallel regime at high concentrations.

  4. Water excretion mechanisms of the kidney studied in the rabbit using tritiated water during the stop-flow assay

    International Nuclear Information System (INIS)

    Morel, F.; Amiel, CI.; Falbriard, A.

    1960-01-01

    The pattern of water turnover in the kidney and the mechanisms of water transfer into the urine have been studied in the rabbit using tritiated water as a tracer and the stop-flow technique. The experiments have given the following results: a) During the interruption of the diuresis, the injected tritiated water is completely exchanged with the water of the renal cortex, but the tracer does not reach the deep regions of the kidney, despite the fact that the blood circulation is maintained in these regions; this suggests that the vascular loops of the vasa recta function as a mechanism of water exchange by countercurrent. b) During the osmotic polyuria following the stop-flow period, the concentration gradient of tritiated water inside the kidney diminishes progressively. The concentration of the tracer in the urine is at all time similar to that existing in the deep medulla and the renal papilla and markedly different from that of the cortex or arterial blood. This fact shows that the molecules of water in the urine excreted do not come from either the glomerular filtrate or the convoluted tubules but from the water contained in the deep regions of the kidney. Also these results indicate that the walls of the collecting ducts have a very high permeability to water diffusion. Reprint of a paper published in Revue francaise d'etudes cliniques et biologiques, Vol. IV, no. 8, p. 773-779, 1959 [fr

  5. Virtual water flows in the international trade of agricultural products of China.

    Science.gov (United States)

    Zhang, Yu; Zhang, Jinhe; Tang, Guorong; Chen, Min; Wang, Lachun

    2016-07-01

    With the rapid development of the economy and population, water scarcity and poor water quality caused by water pollution have become increasingly severe in China. Virtual water trade is a useful tool to alleviate water shortage. This paper focuses on a comprehensive study of China's international virtual water flows from agricultural products trade and completes a diachronic analysis from 2001 to 2013. The results show that China was in trade surplus in relation to the virtual water trade of agricultural products. The exported virtual water amounted to 29.94billionm(3)/yr. while 155.55billionm(3)/yr. was embedded in imported products. The trend that China exported virtual water per year was on the decline while the imported was on a rising trend. Virtual water trade of China was highly concentrated. Not all of the exported products had comparative advantages in virtual water content. Imported products were excessively concentrated on water intensive agricultural products such as soya beans, cotton, and palm oil. The exported virtual water mainly flowed to the Republic of Korea, Hong Kong of China and Japan, while the imported mainly flowed from the United States of America, Brazil and Argentina. From the ethical point of view, the trade partners were classified into four types in terms of "net import" and "water abundance": mutual benefit countries, such as Australia and Canada; unilateral benefit countries, such as Mongolia and Norway; supported countries, such as Egypt and Singapore; and double pressure countries, such as India and Pakistan. Virtual water strategy refers to water resources, agricultural products and human beings. The findings are beneficial for innovating water resources management system, adjusting trade structure, ensuring food security in China, and promoting the construction of national ecological security system. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Water-level changes and directions of ground-water flow in the shallow aquifer, Fallon area, Churchill County, Nevada

    Science.gov (United States)

    Seiler, R.L.; Allander, K.K.

    1993-01-01

    The Truckee-Carson-Pyramid Lake Water Rights Settlement Act of 1990 directed the U.S. Fish and Wildlife Service to acquire water rights for wetland areas in the Carson Desert, Nevada. The public is concerned that htis acquisition of water rights and delivery of the water directly to wildlife areas would result in less recharge to the shallow ground water in the Fallon area and cause domestic wells to go dry. In January 1992, the U.S. Geological Survey, in cooperation with U.S. Fish and Wildlife Service, began a study of the shallow ground-water system in the Fallon area in Churchill County, Nevada. A network of 126 wells in the study area was monitored. Between January and November 1992, water levels in most wells declined, usually less than 2 feet. The maximum measured decline over this period was 2.68 feet in a well near Stillwater Marsh. Between April and July, however, water levels rose in irrigated areas, typically 1 to 2 feet. Newlands Project water deliveries to the study area began soon after the turn of the century. Since then, water levels have risen more than 15 feet across much of the study area. Water lost from unlined irrigtiaon canals caused the stage in Big Soda Lake to rise nearly 60 feet; ground-water levels near the lake have risen 30 to 40 feet. The depth to water in most irrigated areas is now less than 10 feet. The altitude of the water table ranges from 4.025 feet above sea level 11 miles west of Fallon to 3,865 feet in the Stillwater Marsh area. Ground water flows eastward and divides; some flow goes to the northeast toward the Carson Sink and Stillwater areas, and some goes southeastward to Carson Lake.

  7. Fragmented Flows: Water Supply in Los Angeles County

    Science.gov (United States)

    Pincetl, Stephanie; Porse, Erik; Cheng, Deborah

    2016-08-01

    In the Los Angeles metropolitan region, nearly 100 public and private entities are formally involved in the management and distribution of potable water—a legacy rooted in fragmented urban growth in the area and late 19th century convictions about local control of services. Yet, while policy debates focus on new forms of infrastructure, restructured pricing mechanisms, and other technical fixes, the complex institutional architecture of the present system has received little attention. In this paper, we trace the development of this system, describe its interconnections and disjunctures, and demonstrate the invisibility of water infrastructure in LA in multiple ways—through mapping, statistical analysis, and historical texts. Perverse blessings of past water abundance led to a complex, but less than resilient, system with users accustomed to cheap, easily accessible water. We describe the lack of transparency and accountability in the current system, as well as its shortcomings in building needed new infrastructure and instituting new water rate structures. Adapting to increasing water scarcity and likely droughts must include addressing the architecture of water management.

  8. Desirable and undesirable future thoughts call for different scene construction processes.

    Science.gov (United States)

    de Vito, S; Neroni, M A; Gamboz, N; Della Sala, S; Brandimonte, M A

    2015-01-01

    Despite the growing interest in the ability of foreseeing (episodic future thinking), it is still unclear how healthy people construct possible future scenarios. We suggest that different future thoughts require different processes of scene construction. Thirty-five participants were asked to imagine desirable and less desirable future events. Imagining desirable events increased the ease of scene construction, the frequency of life scripts, the number of internal details, and the clarity of sensorial and spatial temporal information. The initial description of general personal knowledge lasted longer in undesirable than in desirable anticipations. Finally, participants were more prone to explicitly indicate autobiographical memory as the main source of their simulations of undesirable episodes, whereas they equally related the simulations of desirable events to autobiographical events or semantic knowledge. These findings show that desirable and undesirable scenarios call for different mechanisms of scene construction. The present study emphasizes that future thinking cannot be considered as a monolithic entity.

  9. Ranking of bank branches with undesirable and fuzzy data: A DEA-based approach

    Directory of Open Access Journals (Sweden)

    Sohrab Kordrostami

    2016-07-01

    Full Text Available Banks are one of the most important financial sectors in order to the economic development of each country. Certainly, efficiency scores and ranks of banks are significant and effective aspects towards future planning. Sometimes the performance of banks must be measured in the presence of undesirable and vague factors. For these reasons in the current paper a procedure based on data envelopment analysis (DEA is introduced for evaluating the efficiency and complete ranking of decision making units (DMUs where undesirable and fuzzy measures exist. To illustrate, in the presence of undesirable and fuzzy measures, DMUs are evaluated by using a fuzzy expected value approach and DMUs with similar efficiency scores are ranked by using constraints and the Maximal Balance Index based on the optimal shadow prices. Afterwards, the efficiency scores of 25 branches of an Iranian commercial bank are evaluated using the proposed method. Also, a complete ranking of bank branches is presented to discriminate branches.

  10. Radar Based Flow and Water Level Forecasting in Sewer Systems:a danisk case study

    OpenAIRE

    Thorndahl, Søren; Rasmussen, Michael R.; Grum, M.; Neve, S. L.

    2009-01-01

    This paper describes the first radar based forecast of flow and/or water level in sewer systems in Denmark. The rainfall is successfully forecasted with a lead time of 1-2 hours, and flow/levels are forecasted an additional ½-1½ hours using models describing the behaviour of the sewer system. Both radar data and flow/water level model are continuously updated using online rain gauges and online in-sewer measurements, in order to make the best possible predictions. The project show very promis...

  11. An analysis direct-contact condensation in horizontal cocurrent stratified flow of steam and cold water

    International Nuclear Information System (INIS)

    Lee, Suk Ho; Kim, Hho Jung

    1992-01-01

    The physical benchmark problem on the direct-contact condensation under the horizontal cocurrent stratified flow was analyzed using the RELAP5/MOD2 and /MOD3 one-dimensional model. Analysis was performed for the Northwestern experiments, which involved condensing steam/water flow in a rectangular channel. The study showed that the RELAP5 interfacial heat transfer model, under the horizontal stratified flow regime, predicted the condensation rate well though the interfacial heat transfer area was underpredicted. However, some discrepancies in water layer thickness and local heat transfer coefficient with experimental results were found especially when there is a wavy interface, and those were satisfied only within the range. (Author)

  12. Pressure drop, steam content and turbulent cross exchange in water/steam flows

    International Nuclear Information System (INIS)

    Teichel, H.

    1978-01-01

    For describing the behaviour of two-phase flows of water and steam with the help of calculating patterns, a number of empirical correlations are required. - In this article, correlations for the friction pressure drop in water/steam flows are compared, as well as for the steam mass and the volumetric steam content with each other and with the test results on simple geometries. As the mutual effect between cooling chanels plays an important part at the longitudinal flow through bar bundles, the appertaining equations are evaluated, in addition. (orig.) 891 HP [de

  13. Water flow through the polypropylene-based geotextiles.

    CSIR Research Space (South Africa)

    Patanaik, A

    2008-06-01

    Full Text Available of incompressible non-Newto- nian fluid through the pores of nonwoven geotextiles can be solved by Navier-Stokes equation15,16 along with Darcy’s law. The Navier-Stokes equation for fluid flow is given by: q @u @t �r h ruþ ruð Þ T � �h i þ q u � Dð Þuþ Dp..., L. Paper Presented in Finite Element Modeling of Textiles and Textile Composites Conference, St-Petersburg, Russia, Septem- ber 26–28, 2007. 15. Gresho, P. M.; Sani, R. L. Incompressible Flow and the Finite Element Method; Wiley: New York, 2000...

  14. Water flow and solute transport through fractured rock

    International Nuclear Information System (INIS)

    Bourke, P.J.; Kingdon, R.D.; Bolt, J.E.; Pascoe, D.M.; Watkins, V.M.B.

    1991-01-01

    In densely fractured slate at the Nirex research site in Cornwall, the positions, orientations and hydraulic conductivities of the 380 fractures intersecting a drill hole between 9 and 50 m depths have been individually measured. These data have been used: - to determine the dimensions of statistically representative volumes of the sheetwork of fractures; - to predict; using discrete flowpath modelling and the NAPSAC code; the total flows into the fractures when large numbers are simultaneously pressurised along various lengths of the hole; Corresponding measurements, which proved the modelling and validated the code to factor of two accuracy, are reported. Possibilities accounting for this factor are noted for experimental investigation, and continuing, more extensive inter-hole flow and transport measurements are outlined. The application of this experimental and theoretical approach for calculating radionuclide transport in less densely fractured rock suitable for waste disposal is discussed. 7 figs., 9 refs

  15. Vibration of helical springs in cross water flow

    International Nuclear Information System (INIS)

    Axisa, F.; Brunet, G.

    1987-05-01

    The purpose of this paper is to present new experimental data on vortex-shedding induced vibration on helical springs subjected to cross-flows. Intense locked-in vibration were observed on the natural modes of axial displacement. A simplified model is tentatively proposed to interpret the experimental data which is based on an analogy with vortex-shedding as observed on straight tube rows

  16. Energy from sea wave thrust and flow of water

    International Nuclear Information System (INIS)

    Sarkar, S.R.

    1996-01-01

    The area adjacent to the tidal rivers, irrigational canal, drain and also the seashore may be energized harnessing the energy from the flow/wave thrust by simply converting it into unidirectional rotating force to drive the generator for power generation. The existing plants are big in size and also fixed in place. A plant which will be a small/portable type is described. 7 refs., figs

  17. A potential approach for low flow selection in water resource supply and management

    Science.gov (United States)

    Ouyang, Ying

    2012-08-01

    SummaryLow flow selections are essential to water resource management, water supply planning, and watershed ecosystem restoration. In this study, a new approach, namely the frequent-low (FL) approach (or frequent-low index), was developed based on the minimum frequent-low flow or level used in minimum flows and/or levels program in northeast Florida, USA. This FL approach was then compared to the conventional 7Q10 approach for low flow selections prior to its applications, using the USGS flow data from the freshwater environment (Big Sunflower River, Mississippi) as well as from the estuarine environment (St. Johns River, Florida). Unlike the FL approach that is associated with the biological and ecological impacts, the 7Q10 approach could lead to the selections of extremely low flows (e.g., near-zero flows) that may hinder its use for establishing criteria to prevent streams from significant harm to biological and ecological communities. Additionally, the 7Q10 approach could not be used when the period of data records is less than 10 years by definition while this may not the case for the FL approach. Results from both approaches showed that the low flows from the Big Sunflower River and the St. Johns River decreased as time elapsed, demonstrating that these two rivers have become drier during the last several decades with a potential of salted water intrusion to the St. Johns River. Results from the FL approach further revealed that the recurrence probability of low flow increased while the recurrence interval of low flow decreased as time elapsed in both rivers, indicating that low flows occurred more frequent in these rivers as time elapsed. This report suggests that the FL approach, developed in this study, is a useful alternative for low flow selections in addition to the 7Q10 approach.

  18. Risk management of undesirable substances in feed following updated risk assessments

    International Nuclear Information System (INIS)

    Verstraete, Frans

    2013-01-01

    Directive 2002/32/EC of 7 May 2002 of the European Parliament and of the Council on undesirable substances in animal feed is the framework for the EU action on undesirable substances in feed. This framework Directive provides: ⁎that products intended for animal feed may enter for use in the Union from third countries, be put into circulation and/or used in the Union only if they are sound, genuine and of merchantable quality and therefore when correctly used do not represent any danger to human health, animal health or to the environment or could adversely affect livestock production. ⁎that in order to protect animal and public health and the environment, maximum levels for specific undesirable substances shall be established where necessary. ⁎for mandatory consultation of a scientific body (EFSA) for all provisions which may have an effect upon public health or animal health or on the environment. ⁎that products intended for animal feed containing levels of an undesirable substance that exceed the established maximum level may not be mixed for dilution purposes with the same, or other, products intended for animal feed and may not be used for the production of compound feed. Based on the provisions and principles laid down in this framework Directive, maximum levels for a whole range of undesirable substances have been established at EU level. During the discussions in view of the adoption of Directive 2002/32/EC, the European Commission made the commitment to review all existing provisions on undesirable substances on the basis of updated scientific risk assessments. Following requests of the European Commission, the Panel on Contaminants in the Food Chain (CONTAM) from the European Food Safety Authority (EFSA) has completed a series of 30 risk assessments undertaken over the last 5 years on undesirable substances in animal feed reviewing the possible risks for animal and human health due to the presence of these substances in animal feed. EU legislation

  19. Risk management of undesirable substances in feed following updated risk assessments

    Energy Technology Data Exchange (ETDEWEB)

    Verstraete, Frans, E-mail: Frans.Verstraete@ec.europa.eu

    2013-08-01

    Directive 2002/32/EC of 7 May 2002 of the European Parliament and of the Council on undesirable substances in animal feed is the framework for the EU action on undesirable substances in feed. This framework Directive provides: ⁎that products intended for animal feed may enter for use in the Union from third countries, be put into circulation and/or used in the Union only if they are sound, genuine and of merchantable quality and therefore when correctly used do not represent any danger to human health, animal health or to the environment or could adversely affect livestock production. ⁎that in order to protect animal and public health and the environment, maximum levels for specific undesirable substances shall be established where necessary. ⁎for mandatory consultation of a scientific body (EFSA) for all provisions which may have an effect upon public health or animal health or on the environment. ⁎that products intended for animal feed containing levels of an undesirable substance that exceed the established maximum level may not be mixed for dilution purposes with the same, or other, products intended for animal feed and may not be used for the production of compound feed. Based on the provisions and principles laid down in this framework Directive, maximum levels for a whole range of undesirable substances have been established at EU level. During the discussions in view of the adoption of Directive 2002/32/EC, the European Commission made the commitment to review all existing provisions on undesirable substances on the basis of updated scientific risk assessments. Following requests of the European Commission, the Panel on Contaminants in the Food Chain (CONTAM) from the European Food Safety Authority (EFSA) has completed a series of 30 risk assessments undertaken over the last 5 years on undesirable substances in animal feed reviewing the possible risks for animal and human health due to the presence of these substances in animal feed. EU legislation

  20. Impacts of impervious cover, water withdrawals, and climate change on river flows in the conterminous US

    Directory of Open Access Journals (Sweden)

    P. V. Caldwell

    2012-08-01

    Full Text Available Rivers are essential to aquatic ecosystem and societal sustainability, but are increasingly impacted by water withdrawals, land-use change, and climate change. The relative and cumulative effects of these stressors on continental river flows are relatively unknown. In this study, we used an integrated water balance and flow routing model to evaluate the impacts of impervious cover and water withdrawal on river flow across the conterminous US at the 8-digit Hydrologic Unit Code (HUC watershed scale. We then estimated the impacts of projected change in withdrawals, impervious cover, and climate under the B1 "Low" and A2 "High" emission scenarios on river flows by 2060. Our results suggest that compared to no impervious cover, 2010 levels of impervious cover increased river flows by 9.9% on average with larger impacts in and downstream of major metropolitan areas. In contrast, compared to no water withdrawals, 2005 withdrawals decreased river flows by 1.4% on average with larger impacts in heavily irrigated arid regions of Western US. By 2060, impacts of climate change were predicted to overwhelm the potential gain in river flow due to future changes in impervious cover and add to the potential reduction in river flows from withdrawals, decreasing mean annual river flows from 2010 levels by 16% on average. However, increases in impervious cover by 2060 may offset the impact of climate change during the growing season in some watersheds. Large water withdrawals will aggravate the predicted impact of climate change on river flows, particularly in the Western US. Predicted ecohydrological impacts of land cover, water withdrawal, and climate change will likely include alteration of the terrestrial water balance, stream channel habitat, riparian and aquatic community structure in snow-dominated basins, and fish and mussel extirpations in heavily impacted watersheds. These changes may also require new infrastructure to support increasing anthropogenic

  1. Ground water flow velocity in the bank of the Columbia River, Hanford, Washington

    International Nuclear Information System (INIS)

    Ballard, S.

    1995-12-01

    To properly characterize the transport of contaminants from the sediments beneath the Hanford Site into the Columbia River, a suite of In Situ Permeable Flow Sensors was deployed to accurately characterize the hydrologic regime in the banks of the river. The three dimensional flow velocity was recorded on an hourly basis from mid May to mid July, 1994 and for one week in September. The first data collection interval coincided with the seasonal high water level in the river while the second interval reflected conditions during relatively low seasonal river stage. Two flow sensors located approximately 50 feet from the river recorded flow directions which correlated very well with river stage, both on seasonal and diurnal time scales. During time intervals characterized by falling river stage, the flow sensors recorded flow toward the river while flow away from the river was recorded during times of rising river stage. The flow sensor near the river in the Hanford Formation recorded a component of flow oriented vertically downward, probably reflecting the details of the hydrostratigraphy in close proximity to the probe. The flow sensor near the river in the Ringold Formation recorded an upward component of flow which dominated the horizontal components most of the time. The upward flow in the Ringold probably reflects regional groundwater flow into the river. The magnitudes of the flow velocities recorded by the flow sensors were lower than expected, probably as a result of drilling induced disturbance of the hydraulic properties of the sediments around the probes. The probes were installed with resonant sonic drilling which may have compacted the sediments immediately surrounding the probes, thereby reducing the hydraulic conductivity adjacent to the probes and diverting the groundwater flow away from the sensors

  2. An experimental investigation of flow instability between two heated parallel channels with supercritical water

    Energy Technology Data Exchange (ETDEWEB)

    Xi, Xi; Xiao, Zejun, E-mail: fabulous_2012@sina.com; Yan, Xiao; Li, Yongliang; Huang, Yanping

    2014-10-15

    Highlights: • Flow instability experiment between two heated channels with supercritical water is carried out. • Two kinds of out of phase flow instability are found and instability boundaries under different working conditions are obtained. • Dynamics characteristics of flow instability are analyzed. - Abstract: Super critical water reactor (SCWR) is the generation IV nuclear reactor in the world. Under normal operation, water enters SCWR from cold leg with a temperature of 280 °C and then leaves the core with a temperature of 500 °C. Due to the sharp change of temperature, there is a huge density change in the core, which could result in potential flow instability and the safety of reactor would be threatened consequently. So it is necessary to carry out relevant investigation in this field. An experimental investigation which concerns with out of phase flow instability between two heated parallel channels with supercritical water has been carried out in this paper. Due to two INCONEL 625 pipes with a thickness of 6.5 mm are adopted, more experimental results are attained. To find out the influence of axial power shape on the onset of flow instability, each heated channel is divided into two sections and the heating power of each section can be controlled separately. Finally the instability boundaries are obtained under different inlet temperatures, axial power shapes, total inlet mass flow rates and system pressures. The dynamics characteristics of out of phase oscillation are also analyzed.

  3. First status report on regional ground-water flow modeling for Vacherie Dome, Louisiana

    International Nuclear Information System (INIS)

    1986-07-01

    Regional ground-water flow within the principal geohydrologic units in the vicinity of Vacherie Dome, Louisiana is evaluated by developing a conceptual model of the flow regime within these units and testing the model using a three-dimensional, finite-difference flow code (SWENT). Semiquantitative sensitivity analyses (a limited parametric study) are conducted to define the system responses to changes in the conceptual model, particularly in regard to the geohydrologic properties. All steps leading to the final results and conclusions are incorporated in this report. The available data utilized in this study are summarized. The conceptual model is defined in terms of the areal and vertical averaging of lithologic units, aquifer properties, and hydrologic boundary conditions. The simulated ground-water flow fields are described with potentiometric surfaces, areas of upward and downward flow across aquitards, tables summarizing the horizontal and vertical volumetric flows through the principal units, ground-water travel times and paths, and Darcy velocities within specified finite-difference blocks. The reported work is the first stage of an ongoing evaluation of Vacherie Dome as a potential repository for high-level radioactive wastes. The results and conclusions should thus be considered preliminary and subject to modification with the collection of additional data. However, the report does provide a useful basis for describing the sensitivity of the conceptualization of ground-water flow to parameterization and, to a lesser extent, the uncertainties in the present conceptualization. 34 refs., 57 figs., 19 tabs

  4. Control-volume-based model of the steam-water injector flow

    Science.gov (United States)

    Kwidziński, Roman

    2010-03-01

    The paper presents equations of a mathematical model to calculate flow parameters in characteristic cross-sections in the steam-water injector. In the model, component parts of the injector (steam nozzle, water nozzle, mixing chamber, condensation wave region, diffuser) are treated as a series of connected control volumes. At first, equations for the steam nozzle and water nozzle are written and solved for known flow parameters at the injector inlet. Next, the flow properties in two-phase flow comprising mixing chamber and condensation wave region are determined from mass, momentum and energy balance equations. Then, water compression in diffuser is taken into account to evaluate the flow parameters at the injector outlet. Irreversible losses due to friction, condensation and shock wave formation are taken into account for the flow in the steam nozzle. In two-phase flow domain, thermal and mechanical nonequilibrium between vapour and liquid is modelled. For diffuser, frictional pressure loss is considered. Comparison of the model predictions with experimental data shows good agreement, with an error not exceeding 15% for discharge (outlet) pressure and 1 K for outlet temperature.

  5. Study on an Undershot Cross-Flow Water Turbine with Straight Blades

    Directory of Open Access Journals (Sweden)

    Yasuyuki Nishi

    2015-01-01

    Full Text Available Small-scale hydroelectric power generation has recently attracted considerable attention. The authors previously proposed an undershot cross-flow water turbine with a very low head suitable for application to open channels. The water turbine was of a cross-flow type and could be used in open channels with the undershot method, remarkably simplifying its design by eliminating guide vanes and the casing. The water turbine was fitted with curved blades (such as the runners of a typical cross-flow water turbine installed in tube channels. However, there was ambiguity as to how the blades’ shape influenced the turbine’s performance and flow field. To resolve this issue, the present study applies straight blades to an undershot cross-flow water turbine and examines the performance and flow field via experiments and numerical analyses. Results reveal that the output power and the turbine efficiency of the Straight Blades runner were greater than those of the Curved Blades runner regardless of the rotational speed. Compared with the Curved Blades runner, the output power and the turbine efficiency of the Straight Blades runner were improved by about 31.7% and about 67.1%, respectively.

  6. Effects of chronic pollution and water flow intermittency on stream biofilms biodegradation capacity.

    Science.gov (United States)

    Rožman, Marko; Acuña, Vicenç; Petrović, Mira

    2018-02-01

    A mesocosm case study was conducted to gain understanding and practical knowledge on biofilm emerging contaminants biodegradation capacity under stressor and multiple stressor conditions. Two real life scenarios: I) biodegradation in a pristine intermittent stream experiencing acute pollution and II) biodegradation in a chronically polluted intermittent stream, were examined via a multifactorial experiment using an artificial stream facility. Stream biofilms were exposed to different water flow conditions i.e. permanent and intermittent water flow. Venlafaxine, a readily biodegradable pharmaceutical was used as a measure of biodegradation capacity while pollution was simulated by a mixture of four emerging contaminants (erythromycin, sulfisoxazole, diclofenac and imidacloprid in addition to venlafaxine) in environmentally relevant concentrations. Biodegradation kinetics monitored via LC-MS/MS was established, statistically evaluated, and used to link biodegradation with stress events. The results suggest that the effects of intermittent flow do not hinder and may even stimulate pristine biofilm biodegradation capacity. Chronic pollution completely reduced biodegradation in permanent water flow experimental treatments while no change in intermittent streams was observed. A combined effect of water flow conditions and emerging contaminants exposure on biodegradation was found. The decrease in biodegradation due to exposure to emerging contaminants is significantly greater in streams with permanent water flow suggesting that the short and medium term biodegradation capacity in intermittent systems may be preserved or even greater than in perennial streams. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Multiregional input-output model for the evaluation of Spanish water flows.

    Science.gov (United States)

    Cazcarro, Ignacio; Duarte, Rosa; Sánchez Chóliz, Julio

    2013-01-01

    We construct a multiregional input-output model for Spain, in order to evaluate the pressures on the water resources, virtual water flows, and water footprints of the regions, and the water impact of trade relationships within Spain and abroad. The study is framed with those interregional input-output models constructed to study water flows and impacts of regions in China, Australia, Mexico, or the UK. To build our database, we reconcile regional IO tables, national and regional accountancy of Spain, trade and water data. Results show an important imbalance between origin of water resources and final destination, with significant water pressures in the South, Mediterranean, and some central regions. The most populated and dynamic regions of Madrid and Barcelona are important drivers of water consumption in Spain. Main virtual water exporters are the South and Central agrarian regions: Andalusia, Castile-La Mancha, Castile-Leon, Aragon, and Extremadura, while the main virtual water importers are the industrialized regions of Madrid, Basque country, and the Mediterranean coast. The paper shows the different location of direct and indirect consumers of water in Spain and how the economic trade and consumption pattern of certain areas has significant impacts on the availability of water resources in other different and often drier regions.

  8. Saturated flow boiling heat transfer in water-heated vertical annulus

    International Nuclear Information System (INIS)

    Sun Licheng; Yan Changqi; Sun Zhonning

    2005-01-01

    This paper describes the saturated flow boiling heat transfer characteristics of water at 1 atm and low velocities in water-heated vertical annuli with equivalent diameters of 10 mm and 6 mm. Test section is consisted of two concentric circular tubes outer of which is made of quartz, so the whole test courses can be visualized. There are three main flow patterns of bubble flow, churn flow and churn-annular flow in the annuli, most important of which is churn flow. Flooding is the mechanism of churn flow and churn can enhance the heat transport between steam and water; Among the three factors of mass flux, inlet subcooling and annulus width, the last one has great effect on heat transport, moderately decreasing the annulus width can enhance the heat transfer; Combined annular flow model with theory of flooding and turbulent Prandtl Number, the numerical value of heat flux is given, the shape of test boiling curve and that of calculated by model is very alike, but there is large discrepancy between test data and calculated results, the most possible reason is that some parameters given by fluid flooding model are based on experimental data of common circular tubes, but not of annuli. Doing more research on flooding in annulus, particularly narrow annulus, is necessary for calculating the saturated boiling in annulus. (authors)

  9. Mode pattern of internal flow in a water droplet on a vibrating hydrophobic surface.

    Science.gov (United States)

    Kim, Hun; Lim, Hee-Chang

    2015-06-04

    The objective of this study is to understand the mode pattern of the internal flow in a water droplet placed on a hydrophobic surface that periodically and vertically vibrates. As a result, a water droplet on a vibrating hydrophobic surface has a typical shape that depends on each resonance mode, and, additionally, we observed a diversified lobe size and internal flows in the water droplet. The size of each lobe at the resonance frequency was relatively greater than that at the neighboring frequencies, and the internal flow of the nth order mode was also observed in the flow visualization. In general, large symmetrical flow streams were generated along the vertical axis in each mode, with a large circulating movement from the bottom to the top, and then to the triple contact line along the droplet surface. In contrast, modes 2 and 4 generated a Y-shaped flow pattern, in which the flow moved to the node point in the lower part of the droplet, but modes 6 and 8 had similar patterns, with only a little difference. In addition, as a result of the PIV measurement, while the flow velocity of mode 4 was faster than that of model 2, those of modes 6 and 8 were almost similar.

  10. Welfare values of sustained urban water flows for recreational and cultural amenities under climate change

    NARCIS (Netherlands)

    Nikouei, A.; Brouwer, R.

    2017-01-01

    The main objective of this study is to estimate the welfare values related to sustained water flows in the Zayandeh-Rud River for recreational and cultural amenities in the urban park of Isfahan City in Iran. As is elsewhere the case in arid regions, the drying up of the river due to growing water

  11. Farm level optimal water management : assistant for irrigation under deficit (FLOW-AID)

    NARCIS (Netherlands)

    Balendonck, J.; Stanghellini, C.; Hemming, J.; Kempkes, F.L.K.; Tuijl, van B.A.J.

    2008-01-01

    FLOW-AID is an on-going 6th Framework European project (2006-2009) with the objective to contribute to sustainable irrigated agriculture by developing an irrigation management system that can be used for crop production in cases with limited water supply and marginal water quality. The project

  12. Farm level optimal water management: Assistant for irrigation under Defecit (FLOW-AID)

    NARCIS (Netherlands)

    Balendonck, J.; Stanghellini, C.; Hemming, J.; Kempkes, F.L.K.; Tuijl, van B.A.J.

    2009-01-01

    Flow-aid is an on-going 6th Framework European project (2006-2009) with the objective to contribute to sustainable irrigated agriculture by developing an irrigation management system that can be used for crop production in cases with limited water supply and marginal water quality. The project

  13. CFD Study of Fluid Flow in an All-glass Evacuated Tube Solar Water Heater

    DEFF Research Database (Denmark)

    Ai, Ning; Fan, Jianhua; Li, Yumin

    2008-01-01

    Abstract: The all-glass evacuated tube solar water heater is one of the most widely used solar thermal technologies. The aim of the paper is to investigate fluid flow in the solar water heater by means of computational fluid dynamics (CFD). The investigation was carried out with a focus on the co...... for future system optimization....

  14. The influence of water flow (reversal) on bond strength development in young masonry

    NARCIS (Netherlands)

    Groot, C.; Larbi, J.

    1999-01-01

    Water loss from the fresh mortar is believed to be related to mortar-brick bond strength development in masonry. Recent research on mortar-brick bond has shown that, particularly, effects of water flow on the composition and the hydration conditions of the mortar-brick interface have to be taken

  15. Within plant resistance to water flow in tomato and sweet melons ...

    African Journals Online (AJOL)

    In the evaporative flux method, measurements of transpiration flux and leaf water potential were used to calculate the total resistance to water flow using Ohm's law analogy. Measurements of tranpiration flux (Q) relationship, plant resistance calculated from the slope of their relationship, ranged from 6.57x10-01 to ...

  16. Numerical modeling of coupled water flow and heat transport in soil and snow

    Science.gov (United States)

    Thijs J. Kelleners; Jeremy Koonce; Rose Shillito; Jelle Dijkema; Markus Berli; Michael H. Young; John M. Frank; William Massman

    2016-01-01

    A one-dimensional vertical numerical model for coupled water flow and heat transport in soil and snow was modified to include all three phases of water: vapor, liquid, and ice. The top boundary condition in the model is driven by incoming precipitation and the surface energy balance. The model was applied to three different terrestrial systems: A warm desert bare...

  17. Experimental study of supercritical water flow and heat transfer in vertical tube

    International Nuclear Information System (INIS)

    Li Hongbo; Yang Jue; Lu Donghua; Gu Hanyang; Zhao Meng

    2012-01-01

    The experiment of flow and heat transfer of supercritical water has been performed on the supercritical water multipurpose test loop co-constructed by China Guangdong Nuclear Power Group and Shanghai Jiao Tong University with a 7.6 mm vertical tube. Heat transfer experimental data is obtained. The results of experimental research of thermal-hydraulic parameters on flow and heat transfer of supercritical water show that: (1) Heat transfer enhancement occurs when the bulk temperature reaches pseudo-critical point with low mass flow velocity; (2) The heat transfer co- efficient and Nusselt number are decreased with the increasing of heat flux; (3) The wall temperature is decreased, but the heat transfer coefficient and Nusselt number are increased with the increasing of mass flow velocity; (4) The wall temperature is increased, but the heat transfer coefficient and Nusselt number are decreased with the increasing of sys- tem pressure. (authors)

  18. Two-phase upward air water flow in a prismatic channel with rectangular base

    International Nuclear Information System (INIS)

    Carvalho Tofani, P. de

    1984-01-01

    Two-phase liquid-gas mixtures provide suitable means to simulate water-water vapor flows, which may occur in nuclear reactor cores. The mastery of physical transport phenomena is of great importance, as far as the analysis of such thermal systems is concerned. Within the framework of thermal-hydraulic programs, experiments have been carried out to investigate the two-phase upward air-water flow structure, in a rectangular test section, by using independent measuring techniques, which comprise direct viewing and photography, electrical probes and gamma-ray attenuation. In this paper, flow pattern maps and correlations for flow pattern transitions, void fraction profiles, liquid film thickness and superficial average void fraction are proposed and compared to available data. (Author) [pt

  19. Bifurcations of a creeping air–water flow in a conical container

    DEFF Research Database (Denmark)

    Balci, Adnan; Brøns, Morten; Herrada, Miguel A.

    2016-01-01

    . They are investigated for (Formula presented.), and (Formula presented.). For small (Formula presented.), the air flow is multi-cellular with clockwise meridional circulation near the disk. The air flow becomes one cellular as (Formula presented.) exceeds a threshold depending on (Formula presented.). For all (Formula...... presented.), the water flow has an unbounded number of eddies whose size and strength diminish as the cone apex is approached. As the water level becomes close to the disk, the outmost water eddy with clockwise meridional circulation expands, reaches the interface, and induces a thin layer...... with anticlockwise circulation in the air. Then this layer expands and occupies the entire air domain. The physical reasons for the flow transformations are provided. The results are of fundamental interest and can be relevant for aerial bioreactors....

  20. Well balancing of the SWE schemes for moving-water steady flows

    Science.gov (United States)

    Caleffi, Valerio; Valiani, Alessandro

    2017-08-01

    In this work, the exact reproduction of a moving-water steady flow via the numerical solution of the one-dimensional shallow water equations is studied. A new scheme based on a modified version of the HLLEM approximate Riemann solver (Dumbser and Balsara (2016) [18]) that exactly preserves the total head and the discharge in the simulation of smooth steady flows and that correctly dissipates mechanical energy in the presence of hydraulic jumps is presented. This model is compared with a selected set of schemes from the literature, including models that exactly preserve quiescent flows and models that exactly preserve moving-water steady flows. The comparison highlights the strengths and weaknesses of the different approaches. In particular, the results show that the increase in accuracy in the steady state reproduction is counterbalanced by a reduced robustness and numerical efficiency of the models. Some solutions to reduce these drawbacks, at the cost of increased algorithm complexity, are presented.

  1. Simulation of the solidification in a channel of a water-cooled glass flow

    Directory of Open Access Journals (Sweden)

    G. E. Ovando Chacon

    2014-12-01

    Full Text Available A computer simulation study of a laminar steady-state glass flow that exits from a channel cooled with water is reported. The simulations are carried out in a two-dimensional, Cartesian channel with a backward-facing step for three different angles of the step and different glass outflow velocities. We studied the interaction of the fluid dynamics, phase change and thermal behavior of the glass flow due to the heat that transfers to the cooling water through the wall of the channel. The temperature, streamline, phase change and pressure fields are obtained and analyzed for the glass flow. Moreover, the temperature increments of the cooling water are characterized. It is shown that, by reducing the glass outflow velocity, the solidification is enhanced; meanwhile, an increase of the step angle also improves the solidification of the glass flow.

  2. Modeling Flow Rate to Estimate Hydraulic Conductivity in a Parabolic Ceramic Water Filter

    Directory of Open Access Journals (Sweden)

    Ileana Wald

    2012-01-01

    Full Text Available In this project we model volumetric flow rate through a parabolic ceramic water filter (CWF to determine how quickly it can process water while still improving its quality. The volumetric flow rate is dependent upon the pore size of the filter, the surface area, and the height of water in the filter (hydraulic head. We derive differential equations governing this flow from the conservation of mass principle and Darcy's Law and find the flow rate with respect to time. We then use methods of calculus to find optimal specifications for the filter. This work is related to the research conducted in Dr. James R. Mihelcic's Civil and Environmental Engineering Lab at USF.

  3. The study on three-dimensional mathematical model of river bed erosion for water-sediment two-phase flow

    Science.gov (United States)

    Fang, Hongwei

    1996-02-01

    Based on the tensor analysis of water-sediment two-phase flow, the basic model equations for clear water flow and sediment-laden flow are deduced in the general curve coordinates for natural water variable-density turbulent flow. Furthermore, corresponding boundary conditions are also presented in connection with the composition and movement of non-uniform bed material. The theoretical results are applied to the calculation of the float open caisson in the construction period and good results are obtained.

  4. Water flow in Sphagnum hummocks: Mesocosm measurements and modelling

    Science.gov (United States)

    Price, Jonathan S.; Whittington, Peter N.

    2010-02-01

    SummaryThe internal water fluxes within Sphagnum mosses critically affect the rate of evaporation and the wetness of the living upper few centimetres of moss (capitula) and the physiological processes (e.g. photosynthesis) that support them. To quantify water fluxes and stores in Sphagnum rubellum hummocks we used a 30 cm high column (mesocosm) of undisturbed hummock moss including the capitula, and applied a number of experiments to investigate (1) staged lowering (and raising) of the water table ( wt) with a manometer tube; (2) pumped seepage of about 0.7 cm d -1 to produce a wt drop of 1.5 cm day -1; and (3) evaporation averaging 3.2 mm d -1. Water content ( θ) at saturation ( θ s) was ˜0.9 cm 3 cm -3 for all depths. Residual water content ( θ r) was 0.2 cm 3 cm -3 at 5 cm depth, increasing to 0.47 cm 3 cm -3 at 25 cm depth. Hydraulic conductivity ( K) of the same top 5 cm layer ranged from 1.8 × 10 -3 m s -1 at θ s to 4 × 10 -8 m s -1 at θ r. By comparison K at 25 cm depth had a much more limited range from 2.3 × 10 -4 m s -1 at θ s to 1.1 × 10 -5 m s -1 at θ r. Staged wt lowering from -10 cm to -30 cm (no evaporation allowed) resulted in an abrupt change in θ that reached a stable value generally within an hour, indicating the responsiveness of moss to drainage. Staged increases also resulted in an abrupt rise in θ, but in some cases several days were required for θ to equilibrate. Pumped seepage resulted in a sequential decline of θ, requiring about 10 days for each layer to reach θ r after the water table dropped below the sensor at the respective depths. Evaporation resulted in a similar pattern of decline but took almost three times as long. The computer simulation Hydrus 1D was used to model the fluxes and provided a good fit for the staged lowering and pumped seepage experiments, but overestimated the water loss by evaporation. We believe the reason for this is that over the longer evaporation experiment, the monolith underwent

  5. Effect of air on water capillary flow in silica nanochannels

    DEFF Research Database (Denmark)

    Zambrano, Harvey; Walther, Jens Honore; Oyarzua, Elton

    2013-01-01

    , with the fabrication of microsystems integrated by nanochannels, a thorough understanding of the transport of fluids in nanoconfinement is required for a successful operation of the functional parts of such devices. In this work, Molecular Dynamics simulations are conducted to study the spontaneous imbibition of water...... in sub 10 nm silica channels. The capillary filling speed is computed in channels subjected to different air pressures. In order to describe the interactions between the species, an effective force field is developed, which is calibrated by reproducing the water contact angle. The results show...... that the capillary filling speed qualitatively follows the classical Washburn model, however, quantitatively it is lower than expected. Furthermore, it is observed that the deviations increase as air pressure is higher. We attribute the deviations to amounts of air trapped at the silica-water interface which leads...

  6. Towards a comprehensive assessment and framework for low and high flow water risks

    Science.gov (United States)

    Motschmann, Alina; Huggel, Christian; Drenkhan, Fabian; León, Christian

    2017-04-01

    Driven by international organizations such as the Intergovernmental Panel on Climate Change (IPCC) the past years have seen a move from a vulnerability concept of climate change impacts towards a risk framework. Risk is now conceived at the intersection of climate-driven hazard and socioeconomic-driven vulnerability and exposure. The concept of risk so far has been mainly adopted for sudden-onset events. However, for slow-onset and cumulative climate change impacts such as changing water resources there is missing clarity and experience how to apply a risk framework. Research has hardly dealt with the challenge of how to integrate both low and high flow risks in a common framework. Comprehensive analyses of risks related to water resources considering climate change within multi-dimensional drivers across different scales are complex and often missing in climate-sensitive mountain regions where data scarcity and inconsistencies represent important limitations. Here we review existing vulnerability and risk assessments of low and high flow water conditions and identify critical conceptual and practical gaps. Based on this, we develop an integrated framework for low and high flow water risks which is applicable to both past and future conditions. The framework explicitly considers a water balance model simulating both water supply and demand on a daily basis. We test and apply this new framework in the highly glacierized Santa River catchment (SRC, Cordillera Blanca, Peru), representative for many developing mountain regions with both low and high flow water risks and poor data availability. In fact, in the SRC, both low and high flow hazards, such as droughts and floods, play a central role especially for agricultural, hydropower, domestic and mining use. During the dry season (austral winter) people are increasingly affected by water scarcity due to shrinking glaciers supplying melt water. On the other hand during the wet season (austral summer) high flow water

  7. Diffusion and flow of water vapours in chromatographic Alumina gel

    International Nuclear Information System (INIS)

    Khan, M.; Shah, H. U.

    2005-01-01

    The kinetics of sorption of water vapours in chromatographic alumina gel was studied. Water vapours are adsorbed on the gel at temperature (15 degree C) at different constant relative pressure from 0.1-0.93 p/p. Rate constant, Effective diffusivities, Knudsen diffusivities and bulk diffusivities were determined through Fick type equation. Total pore volume is 0.498 cc g-1 and specific surface area comes to be 465 m2 g-1 as obtained by Gurvitsch rule and Kieselve's quantities respectively. An average pore radius (hydraulic) is 1.1x10/sub -7/ cm. The study of these quantities provide a strong basis for evaluating surface properties. (author)

  8. GSFLOW - Coupled Ground-Water and Surface-Water Flow Model Based on the Integration of the Precipitation-Runoff Modeling System (PRMS) and the Modular Ground-Water Flow Model (MODFLOW-2005)

    Science.gov (United States)

    Markstrom, Steven L.; Niswonger, Richard G.; Regan, R. Steven; Prudic, David E.; Barlow, Paul M.

    2008-01-01

    The need to assess the effects of variability in climate, biota, geology, and human activities on water availability and flow requires the development of models that couple two or more components of the hydrologic cycle. An integrated hydrologic model called GSFLOW (Ground-water and Surface-water FLOW) was developed to simulate coupled ground-water and surface-water resources. The new model is based on the integration of the U.S. Geological Survey Precipitation-Runoff Modeling System (PRMS) and the U.S. Geological Survey Modular Ground-Water Flow Model (MODFLOW). Additional model components were developed, and existing components were modified, to facilitate integration of the models. Methods were developed to route flow among the PRMS Hydrologic Response Units (HRUs) and between the HRUs and the MODFLOW finite-difference cells. This report describes the organization, concepts, design, and mathematical formulation of all GSFLOW model components. An important aspect of the integrated model design is its ability to conserve water mass and to provide comprehensive water budgets for a location of interest. This report includes descriptions of how water budgets are calculated for the integrated model and for individual model components. GSFLOW provides a robust modeling system for simulating flow through the hydrologic cycle, while allowing for future enhancements to incorporate other simulation techniques.

  9. Application of Tank Model for Predicting Water Balance and Flow Discharge Components of Cisadane Upper Catchment

    Directory of Open Access Journals (Sweden)

    Nana Mulyana Arifjaya

    2012-01-01

    Full Text Available The concept of hydrological tank model was well described into four compartments (tanks. The first tank (tank A comprised of one vertical (qA0 and two lateral (qA1 and qA2 water flow components and tank B comprised of one vertical (qB0 and one lateral (qB1 water flow components. Tank C comprised of one vertical (qC0 and one lateral (qC1 water flow components, whereas tank D comprised of one lateral water flow component (qD1.  These vertical water flows would also contribute to the depletion of water flow in the related tanks but would replenish tanks in the deeper layers. It was assumed that at all lateral water flow components would finally accumulate in one stream, summing-up of the lateral water flow, much or less, should be equal to the water discharge (Qo at specified time concerns. Tank A received precipitation (R and evapo-transpiration (ET which was its gradientof (R-ET over time would become the driving force for the changes of water stored in the soil profiles and thosewater flows leaving the soil layer.  Thus tank model could describe th vertical and horizontal water flow withinthe watershed. The research site was Cisadane Upper Catchment, located at Pasir Buncir Village of CaringinSub-District within the Regency of Bogor in West Java Province.  The elevations ranged 512 –2,235 m above sealevel, with a total drainage area of 1,811.5 ha and total length of main stream of 14,340.7 m.  The land cover wasdominated by  forest  with a total of 1,044.6 ha (57.67%,  upland agriculture with a total of 477.96 ha (26.38%,mixed garden with a total of 92.85 ha(5.13% and semitechnical irigated rice field with a total of 196.09 ha (10,8%.  The soil was classified as hydraquent (96.6% and distropept (3.4%.  Based on the calibration of tank model application in the study area, the resulting coefficient of determination (R2 was 0.72 with model efficiency (NSEof= 0.75, thus tank model could well illustrate the water flow distribution of

  10. Simulation of ground-water flow and land subsidence in the Antelope Valley ground-water basin, California

    Science.gov (United States)

    Leighton, David A.; Phillips, Steven P.

    2003-01-01

    Antelope Valley, California, is a topographically closed basin in the western part of the Mojave Desert, about 50 miles northeast of Los Angeles. The Antelope Valley ground-water basin is about 940 square miles and is separated from the northern part of Antelope Valley by faults and low-lying hills. Prior to 1972, ground water provided more than 90 percent of the total water supply in the valley; since 1972, it has provided between 50 and 90 percent. Most ground-water pumping in the valley occurs in the Antelope Valley ground-water basin, which includes the rapidly growing cities of Lancaster and Palmdale. Ground-water-level declines of more than 200 feet in some parts of the ground-water basin have resulted in an increase in pumping lifts, reduced well efficiency, and land subsidence of more than 6 feet in some areas. Future urban growth and limits on the supply of imported water may continue to increase reliance on ground water. To better understand the ground-water flow system and to develop a tool to aid in effectively managing the water resources, a numerical model of ground-water flow and land subsidence in the Antelope Valley ground-water basin was developed using old and new geohydrologic information. The ground-water flow system consists of three aquifers: the upper, middle, and lower aquifers. The aquifers, which were identified on the basis of the hydrologic properties, age, and depth of the unconsolidated deposits, consist of gravel, sand, silt, and clay alluvial deposits and clay and silty clay lacustrine deposits. Prior to ground-water development in the valley, recharge was primarily the infiltration of runoff from the surrounding mountains. Ground water flowed from the recharge areas to discharge areas around the playas where it discharged either from the aquifer system as evapotranspiration or from springs. Partial barriers to horizontal ground-water flow, such as faults, have been identified in the ground-water basin. Water-level declines owing to

  11. Determination of fan flow and water rate adjustment for off-design cooling tower tests

    International Nuclear Information System (INIS)

    Vance, J.M.

    1984-02-01

    The determination of the performance of a mechanical draft cooling tower requires that the air mass flow through the tower be known. Since this flow is not measured, it has been customary to use the manufacturer's design air flow and adjust it by the one-third power of the ratio of the design to test fan horsepower. The most nearly correct approximation of air flow through a tower can be obtained by incrementally moving through the tower from air inlet to outlet while calculating mass flows, energy balances, and pressure drops for each increment and then utilizing fan curves to determine volumetric and mass flows. This procedure would account for changes in air humidity and density through the tower, evaporation of water, effect of water rate on air pressure drop, and changes in fan characteristics. These type calculations may be within the capabilities of all in the near future, but for the interim, it is recommended that a more elementary approach be used which can be handled with a good calculator and without any proprietary data. This approach depends on certain assumptions which are acceptable if the tower test is conducted within CTI code requirements. The fan must be considered a constant suction volume blower for a given blade pitch. The total pressure at the fan, a function of volumetric flow and wet air density, must be assumed to be unaffected by other considerations, and the fan horsepower must be assumed to change only as volumetric flow and wet air density changes. Given these assumptions, along with design information normally provided with a tower, the determination of air flow through a tower in a test can be made from CTI test data. The air flow, and consequently the water rate adjustment and corrected water to air ratio, are derived and found to be direct functions of horsepower and density and an inverse function of wet air humidities

  12. Mechanism of falling water limitation in two-phase counter flow through single hole vertical channel

    International Nuclear Information System (INIS)

    Sudo, Yukio; Ohnuki, Akira

    1983-01-01

    In the safety evaluation at the time of loss coolant accident, which is a credible accident in LWRs, recently main effort has been concentrated to the optimum evaluation calculation, and the grasp of vapor-liquid two-phase flow phenomena has become important. As one of the important phenomena, there is the limitation of falling water in two-phase counter flow through a vertical channel. This phenomenon is divided into the limitation of falling water stored in an upper plenum to a core through an upper core-supporting plate and a tie plate at the time of reflooding, and the limitation of falling emergency core-cooling water in downcomer channels at the time of reflooding in PWRs, under the presence of rising steam flow. In both cases, the evaluation of the quantity of falling water is important, because it contributes directly to core cooling. In this research, in order to clarify the mechanism of limitation of falling water in two-phase vertical counter flow, first, two-phase flow of air-water system through a single-hole vertical channel was taken up, and the effect of main parameters was experimentally studied. At the same time, the theoretical investigation was performed, and the comparison with the experimental results obtained so far was carried out. The different mechanisms for short and long channels gave the good results. (Kako, I.)

  13. Optimality and Conductivity for Water Flow: From Landscapes, to Unsaturated Soils, to Plant Leaves

    Energy Technology Data Exchange (ETDEWEB)

    Liu, H.H.

    2012-02-23

    Optimality principles have been widely used in many areas. Based on an optimality principle that any flow field will tend toward a minimum in the energy dissipation rate, this work shows that there exists a unified form of conductivity relationship for three different flow systems: landscapes, unsaturated soils and plant leaves. The conductivity, the ratio of water flux to energy gradient, is a power function of water flux although the power value is system dependent. This relationship indicates that to minimize energy dissipation rate for a whole system, water flow has a small resistance (or a large conductivity) at a location of large water flux. Empirical evidence supports validity of the relationship for landscape and unsaturated soils (under gravity dominated conditions). Numerical simulation results also show that the relationship can capture the key features of hydraulic structure for a plant leaf, although more studies are needed to further confirm its validity. Especially, it is of interest that according to this relationship, hydraulic conductivity for gravity-dominated unsaturated flow, unlike that defined in the classic theories, depends on not only capillary pressure (or saturation), but also the water flux. Use of the optimality principle allows for determining useful results that are applicable to a broad range of areas involving highly non-linear processes and may not be possible to obtain from classic theories describing water flow processes.

  14. Effect of water flow rate and feed training on "pacamã" (Siluriforme: Pseudopimelodidae juvenile production

    Directory of Open Access Journals (Sweden)

    R.K. Luz

    2011-08-01

    Full Text Available The effects of different water flow rates and feed training on the production of "pacamã" Lophiosilurus alexandri juveniles were evaluated. In the first experiment, nine day post-hatch larvae (n= 2,400 were stocked at a density of 5 larvae/L. Different water flow (F rates were tested: F1 = 180; F2 = 600; F3 = 1,300; and F4 = 2,600mL/min. Artemia nauplii were offered as food during the first 15 days of active feeding. In the second experiment for feed training, 720 juveniles (total length of 22.2mm were stocked at a density of 1.5 juveniles/L. A water flow rate similar to F1 was used. The use of extruded dry diet was tested, and feed training was done with and without other enhanced flavors (Artemia nauplii or Scott emulsion. The water flow rates did not influence the survival or growth of L. alexandri. Cannibalism occurred during feed training. The worst survival, specific growth rate and high mortality were found with the use of extruded dry diet, while similar values were registered with the different feed training diets used. Reduced water flow rate can be used to lower water consumption during larviculture and feed training of L. alexandri.

  15. Water Flow Investigation on Quartz Sand with 13-interval Stimulated Echo Multi Slice Imaging

    Science.gov (United States)

    Spindler, Natascha; Pohlmeier, Andreas; Galvosas, Petrik

    2011-03-01

    Understanding root water uptake in soils is of high importance for securing nutrition in the context of climate change and linked phenomena like stronger varying weather conditions (draught, strong rain). One step to understand how root water uptake occurs is the knowledge of the water flow in soil towards plant roots. Magnetic Resonance Imaging (MRI) in combination with q-space imaging is potentially the most powerful analytical tool for non-invasive three dimensional visualization of flow and transport in porous media. Numerous attempts have been made to measure local velocity in porous media by combining velocity phase encoding with fast imaging methods, where flow velocities in the vascular bundles of plant stems were investigated. In contrast to water situated in the cellular structure of plants, NMR signal arising from water in the pore space in soil may be much more affected by the presence of internal magnetic field gradients. In this work we account for the existence of these gradients by employing bipolar pulsed field magnetic gradients for velocity encoding. This enables one to study flow through sand (as a model system for soil) at flow rates relevant for the water uptake of plant roots.

  16. Water quality in simulated eutrophic shallow lakes in the presence of periphyton under different flow conditions.

    Science.gov (United States)

    Chen, Shu; Yang, Guolu; Lu, Jing; Wang, Lei

    2018-02-01

    Although the effects of periphyton on water quality and its relationship with flow conditions have been studied by researchers, our understanding about their combined action in eutrophic shallow lakes is poor. In this research, four aquatic model ecosystems with different water circulation rates and hydraulic conditions were constructed to investigate the effect of periphyton and flow condition on water quality. The concentrations of NH 4 + , TP, and chlorophyll-a and flow conditions were determined. The results show that, as a result of the rising nutrient level at the early stage and the decline in the lower limit, the presence of periphyton can make the ecosystem adaptable to a wider range of nutrients concentration. In terms of the flow condition, the circulation rate and hydraulic condition are influential factors for aquatic ecosystem. Higher circulation rate in the ecosystem, on one hand, facilitates the metabolism by accelerating nutrient cycling which is beneficial to water quality; on the other hand, high circulation rate leads to the nutrient lower limit rising which is harmful to water quality improvement. At low velocities, slight differences in hydraulic conditions, vertical velocity gradient and turbulence intensity gradient could affect the quantity of phytoplankton. Our study suggests that, considering environmental effect of periphyton, flow conditions and their combined action is essential for water quality improvement and ecological restoration in eutrophic shallow lakes.

  17. On the design criteria for the evaporated water flow rate in a wet air cooler

    International Nuclear Information System (INIS)

    Bourillot, C.

    1982-01-01

    The author discusses Poppe's formulation used for the modelling of heat exchangers between air and water, in Electricite de France's TEFERI numerical wet atmospheric cooler model: heat transfer laws in unsaturated and saturated air, Bosnjakivic's formula, evaporation coefficient. The theorical results show good agreement with the measurements taken on Neurath's cooler C in West Germany, whatever the ambient temperature (evaporated water flow rate, condensate content of warm air). The author then demonstrates the inadequacy of Merkel's method for calculating evaporated water flow rates, and estimates the influence of the assumptions made on the total error [fr

  18. Trees as indicators of subterranean water flow from a retired radioactive waste disposal site

    International Nuclear Information System (INIS)

    Rickard, W.H.; Kirby, L.J.

    1987-01-01

    Tree sampling helped locate a subterranean flow of tritiated water from a low-level radioactive waste disposal site that had not been detected by well water monitoring alone. Deciduous trees growing in a natural forest on the hillsides downslope from the site were sampled for the presence of tritiated water in sap of maple trees and in leaf water extracted from oak and hickory trees. Elevated concentrations of 3 H were detected in the leaf water extracted from several trees located 50 m downslope from the western boundary of the fenced exclusion zone. A 3-m-deep well drilled near these trees indicated that the source of tritiated water was a narrow zone of subterranean flow

  19. Ultrabroadband THz Time-Domain Spectroscopy of a Free-Flowing Water Film

    DEFF Research Database (Denmark)

    Wang, Tianwu; Pedersen, Pernille Klarskov; Jepsen, Peter Uhd

    2014-01-01

    of liquid water using two different THz-TDS setups. The extracted absorption coefficient and refractive index of water are in agreement with previous results reported in the literature. With this we show that the thin free-flowing liquid film is a versatile tool for windowless, ultrabroadband THz......We demonstrate quantitative ultrabroadband THz time-domain spectroscopy (THz-TDS) of water by application of a 17-$\\mu$m thick gravity-driven wire-guided flow jet of water. The thickness and stability of the water film is accurately measured by an optical intensity crosscorrelator, and the standard...... deviation of the film thickness is less than 500 nm. The cross section of the water film is found to have a biconcave cylindrical lens shape. By transmitting through such a thin film, we perform the first ultrabroadband (0.2–30 THz) THz-TDS across the strongest absorbing part of the infrared spectrum...

  20. Thermal fluid flow analysis in downcomer of JAERI passive safety light water reactor (JPSR)

    International Nuclear Information System (INIS)

    Kunii, K.; Iwamura, T.; Murao, Y.

    1995-01-01

    The residual heat for the JPSR (JAERI Passive Safety Light Water Reactor) is removed by a natural-circulation of coolant flowing through downcomer. The numerical analysis has been performed taking account of the downcomer being a three-dimensional annulus flow pass with the purposes to confirm the abilities of (1) approximation of three-dimensional thermal fluid flow in downcomer to simple one-dimensional one assumed on the preliminary design of the passive residual heat removal system and (2) achievement of an enough driving-force of the natural circulation to remove the residual heat. The following results were obtained : (1) Flow pattern in downcomer shows remarkable three-dimensionality (multi-dimensionality) at lower inlet flow rate not to be able to approximate to one-dimensional flow field. However, the temperature distribution does not deviate from uniform one so much even if the multi-dimensional flow such as large vortex arises. (2) It can be expected to obtain the required enough driving-force at a steady state in any case of inlet flow rate where multi-dimensional flow pattern appears. (3) The increase ratio of the driving-force with the time-integrated coolant amount can be estimated as two functional curves in case of higher and other lower inlet flow rates not dependent only on the respective inlet flow rate. (Author)

  1. HRL Aespoe - two-phase flow experiment - gas and water flow in fractured crystalline rock

    International Nuclear Information System (INIS)

    Kull, H.; Liedtke, L.

    1998-01-01

    (The full text of the contribution follows:) Gas generated from radioactive waste may influence the hydraulic and mechanical properties of the man-made barriers and the immediate surroundings of the repository. Prediction of alteration in fractured crystalline rock is difficult. There is a lack of experimental data, and calibrated models are not yet available. Because of the general importance of this matter the German Federal Ministry for Education, Science, Research and Technology decided to conduct a two-phase flow study at HRL Aespoe within the scope of the co-operation agreement with SKB. Within the presentation an overview of field experiments and modelling studies scheduled until end of '99 are given. Conceptual models for one- and two-phase flow, methodologies and with respect to numerical calculations necessary parameter set-ups are discussed. Common objective of in-situ experiments is to calibrate flow models to improve the reliability of predictions for gas migration through fractured rock mass. Hence, in a defined dipole flow field in niche 2/715 at HRL Aespoe effective hydraulic parameters are evaluated. Numerical modelling of non-isothermal, two-phase, two-component processes is feasible only for two-dimensional representation of a porous medium. To overcome this restriction a computer program will be developed to model three-dimensional, fractured, porous media. Rational aspects of two-phase flow studies are for the designing of geotechnical barriers and for the long-term safety analysis of potential radionuclide transport in a future repository required for the licensing process

  2. Flowing water affects fish fast-starts: escape performance of the Hawaiian stream goby, Sicyopterus stimpsoni.

    Science.gov (United States)

    Diamond, Kelly M; Schoenfuss, Heiko L; Walker, Jeffrey A; Blob, Richard W

    2016-10-01

    Experimental measurements of escape performance in fishes have typically been conducted in still water; however, many fishes inhabit environments with flow that could impact escape behavior. We examined the influences of flow and predator attack direction on the escape behavior of fish, using juveniles of the amphidromous Hawaiian goby Sicyopterus stimpsoni In nature, these fish must escape ambush predation while moving through streams with high-velocity flow. We measured the escape performance of juvenile gobies while exposing them to a range of water velocities encountered in natural streams and stimulating fish from three different directions. Frequency of response across treatments indicated strong effects of flow conditions and attack direction. Juvenile S. stimpsoni had uniformly high response rates for attacks from a caudal direction (opposite flow); however, response rates for attacks from a cranial direction (matching flow) decreased dramatically as flow speed increased. Mechanical stimuli produced by predators attacking in the same direction as flow might be masked by the flow environment, impairing the ability of prey to detect attacks. Thus, the likelihood of successful escape performance in fishes can depend critically on environmental context. © 2016. Published by The Company of Biologists Ltd.

  3. Determination of nitrate in water by flow-injection analysis

    Czech Academy of Sciences Publication Activity Database

    Mikuška, Pavel; Večeřa, Zbyněk

    2001-01-01

    Roč. 8, č. 1 (2001), s. 115-120 ISSN 1231-7098 R&D Projects: GA ČR GA203/98/0943 Grant - others:COPERNICUS(BE) SUB-AERO EVK2-1999-000327 Institutional research plan: CEZ:AV0Z4031919 Keywords : nitrate * chemiluminescence * water Subject RIV: CB - Analytical Chemistry, Separation

  4. Normalization of water flow rate for external fire fighting of the buildings in settlements with zone water supply

    Directory of Open Access Journals (Sweden)

    Deryushev Leonid Georgievich

    2014-12-01

    Full Text Available In the article the requirements for fire safety assurance are justified for the objects, in which water is supplied with account for serial and parallel area zoning. In the process of zoning the district is segregated into such parts, for which head rate in any point of selection of water from network will not exceed 6 bar. In the current regulatory rules the requirements for the calculation of the costs of water points are stated, as well as in case of extinguishing fires at the sites with water-supply systems zones. It is recommended to analyze each zone of the system of water-supply separately, without interrelation with the common water feeders, water consumers and services of fire extinguishing. Such an approach to assign water discharge for fire extinguishing results in the decrease of fire safety of an object, deforms calculation technique of outside systems of water-supply of the similar-type objects located in different parts of the terrain. Taking the number of fires and water consumption for fire suppression by the number of residents in each zone, we thus underestimate the capacity of the pipeline system. It is offered to make changes in Norms and Standards in force on fire safety of settlements. The recommendations on regulation of the number of fires and water flow for fire fighting in residential objects with zoned systems of water-supply are formulated.

  5. The Research on Metrological Characteristics of House Water Meters during Transitional Flow Regimes

    Directory of Open Access Journals (Sweden)

    Inga Briliūtė

    2011-04-01

    Full Text Available The purpose of this research is to find the influence of transitional flow regimes on inlet water meters. Four construction types of mechanical inlet water meters (each capacity Q = 10 m3/h were investigated. The biggest additional volume 0,12–0,26% when Q = 0,2…2 m3/h shows single-jet vane wheel meter. This additional volume is less 0,06–0,13% for the multi-jet concentric water meter. The minimum influence of transitional flow regimes was for turbine water meters till 0,1% for all flow range. The volumetric meters are not sensitive for this effect.Article in Lithuanian

  6. Interfacial condensation heat transfer for countercurrent steam-water wavy flow in a horizontal circular pipe

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyung Won; Chun, Moon Hyun [Korea Advanced Institute of Science and Technolgy, Taejon (Korea, Republic of); Chu, In Cheol [KAERI, Taejon (Korea, Republic of)

    2000-10-01

    An experimental study of interfacial condensation heat transfer has been performed for countercurrent steam-water wavy flow in a horizontal circular pipe. A total of 105 local interfacial condensation heat transfer coefficients have been obtained for various combinations of test parameters. Two empirical Nusselt number correlations were developed and parametric effects of steam and water flow rates and the degree of water subcooling on the condensation heat transfer were examined. For the wavy interface condition, the local Nusselt number is more strongly sensitive to the steam Reynolds number than water Reynolds number as opposed to the case of smooth interface condition. Comparisons of the present circular pipe data with existing correlations showed that existing correlations developed for rectangular channels are not directly applicable to a horizontal circular pipe flow.

  7. A device for pre-separating water-drops in a two-phase flow

    International Nuclear Information System (INIS)

    Andro, Jean; Peyrelongue, J.-P.

    1974-01-01

    The invention relates to the mechanical pre-separation of water-drops in suspension in a flow of saturated steam. To this end, the method comprises the steps of carrying out rough separations by directing the flow towards curved surfaces adapted to deflect that flow and to project the drops onto said surfaces, sucking the film formed by the water-drops displaced by centrifugal force on the outer periphery of said surfaces, directing the steam separated from the water-drops onto five separators so as to extract dry steam and discharging the water provided by the sucking of said surfaces and the five separators. The invention applies to the drying of steam issuing from the high-pressure bodies of nuclear steam-turbines [fr

  8. Investigation and mitigation of condensation induced water hammer by stratified flow experiments

    Science.gov (United States)

    Kadakia, Hiral J.

    This research primarily focuses on the possibility of using stratified flow in preventing an occurrence of condensation induced water hammer (CIWH) in horizontal pipe involving steam and subcooled water. A two-phase flow loop simulating the passive safety systems of an advanced light water reactor was constructed and a series of stratified flow experiments were carried out involving a system of subcooled water, saturated water, and steam. Special instruments were designed to measure steam flow rate and subcooled liquid velocity. These experiments showed that when flow field conditions meet certain criteria CIWH does occur. Flow conditions used in experiments were typically observed in passive safety systems of an advanced light water cooled reactor. This research summarizes a) literature research and other experimental data that signify an occurrence of CIWH, b) experiments in an effort to show an occurrence of CIWH and the ability to prevent CIWH, c) qualitative and quantitative results to underline the mechanism of CIWH, d) experiments that show CIWH can be prevented under certain conditions, and e) guidelines for the safe operating conditions. Based on initial experiment results it was observed that Bernoulli's effect can play an important role in wave formation and instability. A separate effect table top experiment was constructed with plexi-glass. A series of entrance effect tests and stratified experiments were carried out with different fluids to study wave formation and wave bridging. Special test series experiments were carried out to investigate the presence of a saturated layer. The effect of subcooled water and steam flow on wedge length and depth were recorded. These experiments helped create a model which calculates wedge and depth of wedge for a given condition of steam and subcooled water. A very good comparison between the experiment results and the model was obtained. These experiments also showed that the presence of saturated layer can mitigate

  9. Hydrogeology and simulation of ground-water flow near the Lantana Landfill, Palm Beach County, Florida

    Science.gov (United States)

    Russell, G.M.; Wexler, E.J.

    1993-01-01

    The Lantana landfill in Palm Beach County has a surface that is 40 to 50 feet above original ground level and consists of about 250 acres of compacted garbage and trash. Parts of the landfill are below the water table. Surface-resistivity measurements and water-quality analyses indicate that leachate-enriched ground water along the eastern perimeter of the landfill has moved about 500 feet eastward toward an adjacent lake. Concentrations of chloride and nutrients within the leachate-enriched ground water were greater than background concentrations. The surficial aquifer system in the area of the landfill consists primarily of sand of moderate permeability, from land surface to a depth of about 68 feet deep, and consists of sand interbedded with sandstone and limestone of high permeability from a depth of about 68 feet to a depth of 200 feet. The potentiometric surface in the landfill is higher than that in adjacent areas to the east, indicating ground-water movement from the landfill toward a lake to the east. Steady-state simulation of ground-water flow was made using a telescoping-grid technique where a model covering a large area is used to determine boundaries and fluxes for a finer scale model. A regional flow model encompassing a 500-square mile area in southeastern Palm Beach County was used to calculate ground-water fluxes in a 126.5-square mile subregional area. Boundary fluxes calculated by the subregional model were then used to calculate boundary fluxes for a local model of the 3.75-square mile area representing the Lantana landfill site and vicinity. Input data required for simulating ground-water flow in the study area were obtained from the regional flow models, thus, effectively coupling the models. Additional simulations were made using the local flow model to predict effects of possible remedial actions on the movement of solutes in the ground-water system. Possible remedial actions simulated included capping the landfill with an impermeable layer

  10. Measurement of Vapor Flow As an Important Source of Water in Dry Land Eco-Hydrology

    Science.gov (United States)

    Wang, Z.; He, Z.; Wang, Y.; Gao, Z.; Hishida, K.

    2014-12-01

    When the temperature of land surface is lower than that of air and deeper soils, water vapor gathers toward the ground surface where dew maybe formed depending on the prevailing dew point and wind speed. Some plants are able to absorb the dew and vapor flow while the soil can readily absorb both. Certain animals such as desert beetles and ants harvest the dew or fog for daily survival. Recently, it is also realized that the dew and vapor flow can be a life-saving amount of water for plant survival at the driest seasons of the year in arid and semi-arid regions. Researches are conducted to quantify the amount of near-surface vapor flow in arid and semi-arid regions in China and USA. Quantitative leaf water absorption and desorption functions were derived based on laboratory experiments. Results show that plant leaves absorb and release water at different speeds depending on species and varieties. The "ideal" native plants in the dry climates can quickly absorb water and slowly release it. This water-holding capacity of plant is characterized by the absorption and desorption functions derived for plant physiology and water balance studies. Field studies are conducted to measure the dynamic vapor flow movements from the atmosphere and the groundwater table to soil surface. Results show that dew is usually formed on soil and plant surfaces during the daily hours when the temperature gradients are inverted toward the soil surface. The amount of dew harvested using gravels on the soil surface was enough to support water melon agriculture on deserts. The vapor flow can be effectively intercepted by artificially seeded plants in semi-arid regions forming new forests. New studies are attempted to quantify the role of vapor flow for the survival of giant sequoias in the southern Sierra Nevada Mountains of California.

  11. Flow and coherent structures around circular cylinders in shallow water

    Science.gov (United States)

    Zeng, Jie; Constantinescu, George

    2017-06-01

    Eddy-resolving numerical simulations are conducted to investigate the dynamics of the large-scale coherent structures around a circular cylinder in an open channel under very shallow flow conditions where the bed friction significantly affects the wake structure. Results are reported for three test cases, for which the ratio between the cylinder diameter, D, and the channel depth, H, is D/H = 10, 25, and 50, respectively. Simulation results show that a horseshoe vortex system forms in all test cases and the dynamics of the necklace vortices is similar to that during the breakaway sub-regime observed for cases when a laminar horseshoe vortex forms around the base of the cylinder. Given the shallow conditions and turbulence in the incoming channel flow, the necklace vortices occupy a large fraction of the flow depth (they penetrate until the free surface in the shallower cases with D/H = 25 and 50). The oscillations of the necklace vortices become less regular with increasing polar angle magnitude and can induce strong amplification of the bed shear stress beneath their cores. Strong interactions are observed between the legs of the necklace vortices and the eddies shed in the separated shear layers in the cases with D/H = 25 and 50. In these two cases, a vortex-street type wake is formed and strong three-dimensional effects are observed in the near-wake flow. A secondary instability in the form of arrays of co-rotating parallel horizontal vortices develops. Once the roller vortices get away from the cylinder, the horizontal vortices in the array orient themselves along the streamwise direction. This instability is not present for moderately shallow conditions (e.g., D/H ≈ 1) nor for very shallow cases when the wake changes to an unsteady bubble type (e.g., D/H = 50). For cases when this secondary instability is present, the horizontal vortices extend vertically over a large fraction of the flow depth and play an important role in the vertical mixing of fluid

  12. Heat transfer to air-water two-phase flow in slug/churn region

    International Nuclear Information System (INIS)

    Wadekar, V.V.; Tuzla, K.; Chen, J.C.

    1996-01-01

    Measured heat transfer data for air-water two-phase flow in the slug/churn flow region are reported. The measurements were obtained from a 1.3 m tall, 15.7 mm diameter vertical tube test-section. It is observed that the data exhibit different heat transfer characteristics to those predicted by the standard correlations for the convective component of flow boiling heat transfer. Comparison with the predictions of a slug flow model for evaporation shows a significant overprediction of the data. The reason for the overprediction is attributed to the sensible heating requirement of the gas phase. The slug flow model is therefore suitably modified for non-evaporating two-phase flow. This specially adapted model is found to give reasonably good predictions of the measured data

  13. Inlet effects on vertical-downward air–water two-phase flow

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, Shouxu; Mena, Daniel; Kim, Seungjin, E-mail: skim@psu.edu

    2017-02-15

    Highlights: • Inlet effects on two-phase flow parameters in vertical-downward flow are studied. • Flow regimes in the vertical-downward two-phase flow are defined. • Vertical-downward flow regime maps for three inlet configurations are developed. • Frictional pressure loss analysis for three different inlets is performed. • Database of local two-phase flow parameters for each inlet configuration. - Abstract: This paper focuses on investigating the geometric effects of inlets on global and local two-phase flow parameters in vertical-downward air–water two-phase flow. Flow visualization, frictional pressure loss analysis, and local experiments are performed in a test facility constructed from 50.8 mm inner diameter acrylic pipes. Three types of inlets of interest are studied: (1) two-phase flow injector without a flow straightener (Type A), (2) two-phase flow injector with a flow straightener (Type B), and (3) injection through a horizontal-to-vertical-downward 90° vertical elbow (Type C). A detailed flow visualization study is performed to characterize flow regimes including bubbly, slug, churn-turbulent, and annular flow. Flow regime maps for each inlet are developed and compared to identify the effects of each inlet. Frictional pressure loss analysis shows that the Lockhart–Martinelli method is capable of correlating the frictional loss data acquired for Type B and Type C inlets with a coefficient value of C = 25, but additional data may be needed to model the Type A inlet. Local two-phase flow parameters measured by a four-sensor conductivity probe in four bubbly and near bubbly flow conditions are analyzed. It is observed that vertical-downward two-phase flow has a characteristic center-peaked void profile as opposed to a wall-peaked profile as seen in vertical-upward flow. Furthermore, it is shown that the Type A inlet results in the most pronounced center-peaked void fraction profile, due to the coring phenomenon. Type B and Type C inlets

  14. Dynamic features of bubble induced by a nanosecond pulse laser in still and flowing water

    Science.gov (United States)

    Charee, Wisan; Tangwarodomnukun, Viboon

    2018-03-01

    Underwater laser ablation techniques have been developed and employed to synthesis nanoparticles, to texture workpiece surface and to assist the material removal in laser machining process. However, the understanding of laser-material-water interactions, bubble formation and effects of water flow on ablation performance has still been very limited. This paper thus aims at exploring the formation and collapse of bubbles during the laser ablation of silicon in water. The effects of water flow rate on bubble formation and its consequences to the laser disturbance and cut features obtained in silicon were observed by using a high speed camera. A nanosecond pulse laser emitting the laser pulse energy of 0.2-0.5 mJ was employed in the experiment. The results showed that the bubble size was found to increase with the laser pulse energy. The use of high water flow rate can importantly facilitate the ejection of ablated particles from the workpiece surface, hence resulting in less deposition to the work surface and minimizing any disturbance to the laser beam during the ablation in water. Furthermore, a clean micro-groove in silicon wafer can successfully be produced when the process was performed in the high water flow rate condition. The findings of this study could provide an essential guideline for process selection, control and improvement in the laser micro-/submicro-fabrication using the underwater technique.

  15. Complexity in the validation of ground-water travel time in fractured flow and transport systems

    International Nuclear Information System (INIS)

    Davies, P.B.; Hunter, R.L.; Pickens, J.F.

    1991-01-01

    Ground-water travel time is a widely used concept in site assessment for radioactive waste disposal. While ground-water travel time was originally conceived to provide a simple performance measure for evaluating repository sites, its definition in many flow and transport environments is ambiguous. The U.S. Department of Energy siting guidelines (10 CFR 960) define ground-water travel time as the time required for a unit volume of water to travel between two locations, calculated by dividing travel-path length by the quotient of average ground-water flux and effective porosity. Defining a meaningful effective porosity in a fractured porous material is a significant problem. Although the Waste Isolation Pilot Plant (WIPP) is not subject to specific requirements for ground-water travel time, travel times have been computed under a variety of model assumptions. Recently completed model analyses for WIPP illustrate the difficulties in applying a ground-water travel-time performance measure to flow and transport in fractured, fully saturated flow systems. Computer code used: SWIFT II (flow and transport code). 4 figs., 12 refs

  16. Squirt flow due to interfacial water films in hydrate bearing sediments

    Directory of Open Access Journals (Sweden)

    K. Sell

    2018-05-01

    Full Text Available Sediments containing gas hydrate dispersed in the pore space are known to show a characteristic seismic anomaly which is a high attenuation along with increasing seismic velocities. Currently, this observation cannot be fully explained albeit squirt-flow type mechanisms on the microscale have been speculated to be the cause. Recent major findings from in situ experiments, using the gas in excess and water in excess formation method, and coupled with high-resolution synchrotron-based X-ray micro-tomography, have revealed the systematic presence of thin water films between the quartz grains and the encrusting hydrate. The data obtained from these experiments underwent an image processing procedure to quantify the thicknesses and geometries of the aforementioned interfacial water films. Overall, the water films vary from sub-micrometer to a few micrometers in thickness. In addition, some of the water films interconnect through water bridges. This geometrical analysis is used to propose a new conceptual squirt flow model for hydrate bearing sediments. A series of numerical simulations is performed considering variations of the proposed model to study seismic attenuation caused by such thin water films. Our results support previous speculation that squirt flow can explain high attenuation at seismic frequencies in hydrate bearing sediments, but based on a conceptual squirt flow model which is geometrically different than those previously considered.

  17. The Finite Element Analysis for a Mini-Conductance Probe in Horizontal Oil-Water Two-Phase Flow

    Directory of Open Access Journals (Sweden)

    Weihang Kong

    2016-08-01

    Full Text Available Oil-water two-phase flow is widespread in petroleum industry processes. The study of oil-water two-phase flow in horizontal pipes and the liquid holdup measurement of oil-water two-phase flow are of great importance for the optimization of the oil production process. This paper presents a novel sensor, i.e., a mini-conductance probe (MCP for measuring pure-water phase conductivity of oil-water segregated flow in horizontal pipes. The MCP solves the difficult problem of obtaining the pure-water correction for water holdup measurements by using a ring-shaped conductivity water-cut meter (RSCWCM. Firstly, using the finite element method (FEM, the spatial sensitivity field of the MCP is investigated and the optimized MCP geometry structure is determined in terms of the characteristic parameters. Then, the responses of the MCP for the oil-water segregated flow are calculated, and it is found that the MCP has better stability and sensitivity to the variation of water-layer thickness in the condition of high water holdup and low flow velocity. Finally, the static experiments for the oil-water segregated flow were carried out and a novel calibration method for pure-water phase conductivity measurements was presented. The validity of the pure-water phase conductivity measurement with segregated flow in horizontal pipes was verified by experimental results.

  18. The Finite Element Analysis for a Mini-Conductance Probe in Horizontal Oil-Water Two-Phase Flow.

    Science.gov (United States)

    Kong, Weihang; Kong, Lingfu; Li, Lei; Liu, Xingbin; Xie, Ronghua; Li, Jun; Tang, Haitao

    2016-08-24

    Oil-water two-phase flow is widespread in petroleum industry processes. The study of oil-water two-phase flow in horizontal pipes and the liquid holdup measurement of oil-water two-phase flow are of great importance for the optimization of the oil production process. This paper presents a novel sensor, i.e., a mini-conductance probe (MCP) for measuring pure-water phase conductivity of oil-water segregated flow in horizontal pipes. The MCP solves the difficult problem of obtaining the pure-water correction for water holdup measurements by using a ring-shaped conductivity water-cut meter (RSCWCM). Firstly, using the finite element method (FEM), the spatial sensitivity field of the MCP is investigated and the optimized MCP geometry structure is determined in terms of the characteristic parameters. Then, the responses of the MCP for the oil-water segregated flow are calculated, and it is found that the MCP has better stability and sensitivity to the variation of water-layer thickness in the condition of high water holdup and low flow velocity. Finally, the static experiments for the oil-water segregated flow were carried out and a novel calibration method for pure-water phase conductivity measurements was presented. The validity of the pure-water phase conductivity measurement with segregated flow in horizontal pipes was verified by experimental results.

  19. Array diagnostics, spatial resolution, and filtering of undesired radiation with the 3D reconstruction algorithm

    DEFF Research Database (Denmark)

    Cappellin, C.; Pivnenko, Sergey; Jørgensen, E.

    2013-01-01

    This paper focuses on three important features of the 3D reconstruction algorithm of DIATOOL: the identification of array elements improper functioning and failure, the obtainable spatial resolution of the reconstructed fields and currents, and the filtering of undesired radiation and scattering...

  20. Relationships between College Students' Credit Card Debt, Undesirable Academic Behaviors and Cognitions, and Academic Performance

    Science.gov (United States)

    Hogan, Eileen A.; Bryant, Sarah K.; Overymyer-Day, Leslie E.

    2013-01-01

    The acquisition of credit card debt by college students has long been a topic of concern. This study explores relationships among debt, undesirable academic behaviors and cognitions, and academic performance, through surveys of 338 students in a public university, replicating two past measures of credit card debt and creating new measures of…

  1. A survey on the presence of undesirable botanical substances in feed in the European Union

    NARCIS (Netherlands)

    Raamsdonk, van L.W.D.; Vancutsem, J.; Jorgensen, J.S.

    2009-01-01

    Directive 2002/32/EC of the European Parliament and of the Council of 7 May 2002 on undesirable substances in animal feed lists a range of substances from botanical origin (weed seeds) and additionally some chemical compounds directly originating from specific weeds. In order to examine the actual

  2. School Social Workers' Perceived Efficacy at Tasks Related to Curbing Suspension and Undesirable Behaviors

    Science.gov (United States)

    Teasley, Martell L.; Miller, Christina R.

    2011-01-01

    This study explores school social workers' perceptions of their ability to successfully engage in practice tasks that reduce the likelihood of school suspension and undesirable behaviors among racial and ethnic groups within diverse geographical locations (urban, suburban, and rural). Using survey research methods with a convenience sample, 201…

  3. Implicit analysis of the transient water flow with dissolved air

    Directory of Open Access Journals (Sweden)

    J. Twyman

    2018-01-01

    Full Text Available The implicit finite-difference method (IFDM for solving a system that transports water with dissolved air using a fixed (or variable rectangular space-time mesh defined by the specified time step method is applied. The air content in the fluid modifies both the wave speed and the Courant number, which makes it inconvenient to apply the traditional Method of Characteristics (MOC and other explicit schemes due to their impossibility to simulate the changes in magnitude, shape and frequency of the pressures train. The conclusion is that the IFDM delivers an accurate and stable solution, with a good adjustment level with respect to a classical case reported in the literature, being a valid alternative for the transient solution in systems that transport water with dissolved air.

  4. South Asia river flow projections and their implications for water resources

    Science.gov (United States)

    Mathison, C.; Wiltshire, A. J.; Falloon, P.; Challinor, A. J.

    2015-06-01

    South Asia is a region with a large and rising population and a high dependance on industries sensitive to water resource such as agriculture. The climate is hugely variable with the region relying on both the Asian Summer Monsoon (ASM) and glaciers for its supply of fresh water. In recent years, changes in the ASM, fears over the rapid retreat of glaciers and the increasing demand for water resources for domestic and industrial use, have caused concern over the reliability of water resources both in the present day and future for this region. The climate of South Asia means it is one of the most irrigated agricultural regions in the world, therefore pressures on water resource affecting the availability of water for irrigation could adversely affect crop yields and therefore food production. In this paper we present the first 25 km resolution regional climate projections of river flow for the South Asia region. ERA-Interim, together with two global climate models (GCMs), which represent the present day processes, particularly the monsoon, reasonably well are downscaled using a regional climate model (RCM) for the periods; 1990-2006 for ERA-Interim and 1960-2100 for the two GCMs. The RCM river flow is routed using a river-routing model to allow analysis of present day and future river flows through comparison with river gauge observations, where available. In this analysis we compare the river flow rate for 12 gauges selected to represent the largest river basins for this region; Ganges, Indus and Brahmaputra basins and characterize the changing conditions from east to west across the Himalayan arc. Observations of precipitation and runoff in this region have large or unknown uncertainties, are short in length or are outside the simulation period, hindering model development and validation designed to improve understanding of the water cycle for this region. In the absence of robust observations for South Asia, a downscaled ERA-Interim RCM simulation provides a

  5. Data flows and water woes: The Utah Data Center

    Directory of Open Access Journals (Sweden)

    Mél Hogan

    2015-07-01

    Full Text Available Using a new materialist line of questioning that looks at the agential potentialities of water and its entanglements with Big Data and surveillance, this article explores how the recent Snowden revelations about the National Security Agency (NSA have reignited media scholars to engage with the infrastructures that enable intercepting, hosting, and processing immeasurable amounts of data. Focusing on the expansive architecture, location, and resource dependence of the NSA’s Utah Data Center, I demonstrate how surveillance and privacy can never be disconnected from the material infrastructures that allow and render natural the epistemological state of mass surveillance. Specifically, I explore the NSA’s infrastructure and the million of gallons of water it requires daily to cool its servers, while located in one of the driest states in the US. Complicating surveillance beyond the NSA, as also already imbricated with various social media companies, this article questions the emplacement and impact of corporate data centers more generally, and the changes they are causing to the landscape and local economies. I look at how water is an intriguing and politically relevant part of the surveillance infrastructure and how it has been constructed as the main tool for activism in this case, and how it may eventually help transform the public’s conceptualization of Big Data, as deeply material.

  6. Measurement of Vertical Oil-in-water Two-phase Flow Using Dual-modality ERT-EMF System

    OpenAIRE

    Faraj, Yousef; Wang, Mi; Jia, Jiabin; Wang, Qiang; Xie, Cheng-gang; Oddie, Gary; Primrose , Ken; Qiu, Changhua

    2015-01-01

    Oil-in-water two-phase flows are often encountered in the upstream petroleum industry. The measurement of phase flow rates is of particular importance for managing oil production and water disposal and/or water reinjection. The complexity of oil-in-water flow structures creates a challenge to flow measurement. This paper proposes a new method of two-phase flow metering, which is based on the use of dual-modality system and multidimensional data fusion. The Electrical Resistance Tomography sys...

  7. Multivariate multiscale complex network analysis of vertical upward oil-water two-phase flow in a small diameter pipe.

    Science.gov (United States)

    Gao, Zhong-Ke; Yang, Yu-Xuan; Zhai, Lu-Sheng; Dang, Wei-Dong; Yu, Jia-Liang; Jin, Ning-De

    2016-02-02

    High water cut and low velocity vertical upward oil-water two-phase flow is a typical complex system with the features of multiscale, unstable and non-homogenous. We first measure local flow information by using distributed conductance sensor and then develop a multivariate multiscale complex network (MMCN) to reveal the dispersed oil-in-water local flow behavior. Specifically, we infer complex networks at different scales from multi-channel measurements for three typical vertical oil-in-water flow patterns. Then we characterize the generated multiscale complex networks in terms of network clustering measure. The results suggest that the clustering coefficient entropy from the MMCN not only allows indicating the oil-in-water flow pattern transition but also enables to probe the dynamical flow behavior governing the transitions of vertical oil-water two-phase flow.

  8. Estimation of natural historical flows for the Manitowish River near Manitowish Waters, Wisconsin

    Science.gov (United States)

    Juckem, Paul F.; Reneau, Paul C.; Robertson, Dale M.

    2012-01-01

    The Wisconsin Department of Natural Resources is charged with oversight of dam operations throughout Wisconsin and is considering modifications to the operating orders for the Rest Lake Dam in Vilas County, Wisconsin. State law requires that the operation orders be tied to natural low flows at the dam. Because the presence of the dam confounds measurement of natural flows, the U.S. Geological Survey, in cooperation with the Wisconsin Department of Natural Resources, installed streamflow-gaging stations and developed two statistical methods to improve estimates of natural flows at the Rest Lake Dam. Two independent methods were used to estimate daily natural flow for the Manitowish River approximately 1 mile downstream of the Rest Lake Dam. The first method was an adjusted drainage-area ratio method, which used a regression analysis that related measured water yield (flow divided by watershed area) from short-term (2009–11) gaging stations upstream of the Manitowish Chain of Lakes to the water yield from two nearby long-term gaging stations in order to extend the flow record (1991–2011). In this approach, the computed flows into the Chain of Lakes at the upstream gaging stations were multiplied by a coefficient to account for the monthly hydrologic contributions (precipitation, evaporation, groundwater, and runoff) associated with the additional watershed area between the upstream gaging stations and the dam at the outlet of the Chain of Lakes (Rest Lake Dam). The second method used to estimate daily natural flow at the Rest Lake Dam was a water-budget approach, which used lake stage and dam outflow data provided by the dam operator. A water-budget model was constructed and then calibrated with an automated parameter-estimation program by matching simulated flow-duration statistics with measured flow-duration statistics at the upstream gaging stations. After calibration of the water-budget model, the model was used to compute natural flow at the dam from 1973 to

  9. Protein synthesis inhibitors attenuate water flow in vasopressin-stimulated toad urinary bladder

    International Nuclear Information System (INIS)

    Hoch, B.S.; Ast, M.B.; Fusco, M.J.; Jacoby, M.; Levine, S.D.

    1988-01-01

    Vasopressin stimulates the introduction of aggregated particles, which may represent pathways for water flow, into the luminal membrane of toad urinary bladder. It is not known whether water transport pathways are degraded on removal from membrane or whether they are recycled. The authors examined the effect of the protein synthesis inhibitors cycloheximide and puromycin using repeated 30-min cycles of vasopressin followed by washout of vasopressin, all in the presence of an osmotic gradient, a protocol that maximizes aggregate turnover. High dose cycloheximide inhibited flow immediately. Low dose cycloheximide did not affect initial flow. In the absence of vasopressin, inhibition did not develop. Despite the inhibition of flow in vasopressin-treated tissues, the cAMP-dependent protein kinase ratio was elevated in cycloheximide-treated tissues, suggesting modulation at a distal site in the stimulatory cascade. [ 14 C]urea permeability was not inhibited by cycloheximide. Puromycin also inhibited water flow by the fourth challenge with vasopressin. The data suggest that protein synthesis inhibitors attenuate flow at a site that is distal to cAMP-dependent protein kinase. However, the reversal of inhibition in MIX-treated tissues suggests that the water pathway can be fully manifested given suitable stimulation. They conclude that either large stores of the transport system are available or that the transport system is extensively recycled on retrieval from the membrane

  10. Investigation of low-frequency-oscillating water flow in metal foam with 10 pores per inch

    Science.gov (United States)

    Bağcı, Ö.; Arbak, A.; De Paepe, M.; Dukhan, N.

    2018-01-01

    In this study, oscillating water flow in metal foam with open cells is investigated experimentally. The metal foam sample has a porosity of 88% and 10 pores. The water was oscillated in the test section with three frequencies between 0.116 Hz and 0.348 Hz, which are considered low for water oscillation, and three flow displacements ranging between 74.35 mm and 111.53 mm. The combinations of frequencies of displacements were studied for their impacts of dimensional and non-dimensional pressure loss quantities. To this purpose, friction factor was correlated as a function of kinetic Reynolds number. The same metal foam sample was studied by exposing it to steady-state water flow to investigate its permeability and drag coefficient in low-velocity flow regimes. The friction factor distribution for oscillating flow was found to be over that found for steady state. The outcomes of the study are important for studying heat transfer under the same flow conditions.

  11. Water flow in bedrock; estimation of influence of transmissive shaft and borehole

    International Nuclear Information System (INIS)

    Andersson, L.; Neretnieks, J.; Rasmuson, A.

    1983-01-01

    The bedrock, a system of large and small fractures that permit water transport through the rock mass. The water content of the bedrock can, under varying hydrostatic pressure conditions, give rise to different flow patterns via boreholes or shafts drilled through the rock. A case is dealt with where a borehole connects a low point in the terrain with a point in the repository where the hydrostatic pressure is higher than at the mouth of the borehole. The situation may be conceived as having arisen when the area was investigated and a hole was drilled at an angle down from the valley to a point below the high point in the area. If the borehole is not sealed, an artesian well may be created. The conductivity used, 2 times 10- 9 m/s, presumes that the repository has been emplaced in average quality rock at this depth. In reality, the repository site will be selected where the rock is better than average. In reality, a shaft - even if it is imperfectly backfilled - or a borehole exerts a flow resistance that reduces the available pressure difference at a depth of 500 m. Taken together, these factors indicate that approx. 5 m 3 /(year, 5 m) is the water flow that can be expected to emerge from the repository through a shaft or a borehole. Only this flow can have been contaminated with escaping substances from the repository area. Water that flows in from other parts of the hole dilutes this flow considerably. (G.B.)

  12. Neuronal responses to water flow in the marine slug tritonia diomedea

    Directory of Open Access Journals (Sweden)

    Jeffrey Blackwell

    2005-07-01

    Full Text Available The marine slug Tritonia diomedea must rely on its ability to touch and smell in order to navigate because it is blind. The primary factor that influences its crawling direction is the direction of water flow (caused by tides in nature. The sensory cells that detect flow and determine flow direction have not been identified. The lateral branch of Cerebral Nerve 2 (latCeN2 has been identified as the nerve that carries sensory axons to the brain from the flow receptors inthe oral tentacles. Backfilling this nerve to the brain resulted in the labeling of a number of cells located throughout the brain. Most of the labeled cells are concentrated in the cerebral ganglion where the nerve enters the brain. The medial and lateral branches of CeN2 were backfilled for comparison of the pattern of cells from each nerve. A map of the cells innervated by latCeN2 reveals the location of the stained cells. Extracellular recording from latCeN2 revealed its involvement in the detection of water flow and orientation. The nerve becomes active in response to water flow stimulation. Intracellular recordings of the electrical activity of these cells in a live animal will be the next step to determine if these cells are the flow receptors.

  13. Volcanic flows versus water- and ice-related outburst deposits in eastern Hellas: A comparison

    Science.gov (United States)

    Voelker, M.; Hauber, E.; Stephan, K.; Jaumann, R.

    2018-06-01

    Hellas Planitia is one of the major topographic sinks on Mars for the deposition of any kind of sediments. We report on our observations of sheet deposits in the eastern part of the basin that are apparently related to the Dao Vallis outflow channel. The deposits have lobate flow fronts and a thickness of a few decameters. Despite their generally smooth surface, some distinctive textures and patterns can be identified, such as longitudinal lineations, distributive channels, and polygons. We compared these deposits to other sheet deposits on Mars and tested three hypotheses of their origin: volcanic flows as well as water- and ice-related mass wastings. Despite some similarities to volcanic sheet flows on Mars, we found several morphological characteristics that are not known for sheet lava flows; for example conically arranged lineations and channel systems very similar to fluvial incisions. We also reject an ice-related formation similar to terrestrial rock-ice avalanches, as there is no sufficient relief energy to explain their extent and location. A water-related origin appears most consistent with our observations, and we favor an emplacement by fluvially-driven mass wasting processes, e.g., debris flows. Assuming a water-related origin, we calculated the amount of water that would be required to deposit such large sedimentary bodies for different flow types. Our calculations show a large range of possible water volumes, from 64 to 2,042 km³, depending on the specific flow mechanism. The close link to Dao Vallis makes these deposits a unique place to study the deposition of outflow channel sediments, as the deposits of other outflow channels on Mars, such as those around Chryse Planitia, are mostly buried by younger sediments and volcanic flows.

  14. Higher energy efficiency and better water quality by using model predictive flow control at water supply systems

    NARCIS (Netherlands)

    Bakker, M.; Verberk, J.Q.J.C.; Palmen, L.J.; Sperber, V.; Bakker, G.

    2011-01-01

    Half of all water supply systems in the Netherlands are controlled by model predictive flow control; the other half are controlled by conventional level based control. The differences between conventional level based control and model predictive control were investigated in experiments at five full

  15. Using a Content Management System for Integrated Water Quantity, Quality and Instream Flows Modeling

    Science.gov (United States)

    Burgholzer, R.; Brogan, C. O.; Scott, D.; Keys, T.

    2017-12-01

    With increased population and water demand, in-stream flows can become depleted by consumptive uses and dilution of permitted discharges may be compromised. Reduced flows downstream of water withdrawals may increase the violation rate of bacterial concentrations from direct deposition by livestock and wildlife. Water storage reservoirs are constructed and operated to insure more stable supplies for consumptive demands and dilution flows, however their use comes at the cost of increased evaporative losses, potential for thermal pollution, interrupted fish migration, and reduced flooding events that are critical to maintain habitat and water quality. Due to this complex interrelationship between water quantity, quality and instream habitat comprehensive multi-disciplinary models must be developed to insure long-term sustainability of water resources and to avoid conflicts between drinking water, food and energy production, and aquatic biota. The Commonwealth of Virginia funded the expansion of the Chesapeake Bay Program Phase 5 model to cover the entire state, and has been using this model to evaluate water supply permit and planning since 2009. This integrated modeling system combines a content management system (Drupal and PHP) for model input data and leverages the modularity of HSPF with the custom segmentation and parameterization routines programmed by modelers working with the Chesapeake Bay Program. The model has been applied to over 30 Virginia Water Permits, instream flows and aquatic habitat models and a Virginias 30 year water supply demand projections. Future versions will leverage the Bay Model auto-calibration routines for adding small-scale water supply and TMDL models, utilize climate change scenarios, and integrate Virginia's reservoir management modules into the Chesapeake Bay watershed model, feeding projected demand and operational changes back up to EPA models to improve the realism of future Bay-wide simulations.

  16. Hydraulic Bureaucracies and the Hydraulic Mission: Flows of Water, Flows of Power

    Directory of Open Access Journals (Sweden)

    François Molle

    2009-10-01

    Full Text Available Anchored in 19th century scientism and an ideology of the domination of nature, inspired by colonial hydraulic feats, and fuelled by technological improvements in high dam constructions and power generation and transmission, large-scale water resources development has been a defining feature of the 20th century. Whether out of a need to increase food production, raise rural incomes, or strengthen state building and the legitimacy of the state, governments – North and South, East and West – embraced the 'hydraulic mission' and entrusted it to powerful state water bureaucracies (hydrocracies. Engaged in the pursuit of iconic and symbolic projects, the massive damming of river systems, and the expansion of large-scale public irrigation these hydrocracies have long remained out of reach. While they have enormously contributed to actual welfare, including energy and food generation, flood protection and water supply to urban areas, infrastructural development has often become an end in itself, rather than a means to an end, fuelling rent-seeking and symbolising state power. In many places projects have been challenged on the basis of their economic, social or environmental impacts. Water bureaucracies have been challenged internally (within the state bureaucracies or through political changes and externally (by critiques from civil society and academia, or by reduced funding. They have endeavoured to respond to these challenges by reinventing themselves or deflecting reforms. This paper analyses these transformations, from the emergence of the hydraulic mission and associated water bureaucracies to their adjustment and responses to changing conditions.

  17. Estimation of daily flow rate of photovoltaic water pumping systems using solar radiation data

    Directory of Open Access Journals (Sweden)

    M. Benghanem

    2018-03-01

    Full Text Available This paper presents a simple model which allows us to contribute in the studies of photovoltaic (PV water pumping systems sizing. The nonlinear relation between water flow rate and solar power has been obtained experimentally in a first step and then used for performance prediction. The model proposed enables us to simulate the water flow rate using solar radiation data for different heads (50 m, 60 m, 70 m and 80 m and for 8S × 3P PV array configuration. The experimental data are obtained with our pumping test facility located at Madinah site (Saudi Arabia. The performances are calculated using the measured solar radiation data of different locations in Saudi Arabia. Knowing the solar radiation data, we have estimated with a good precision the water flow rate Q in five locations (Al-Jouf, Solar Village, AL-Ahsa, Madinah and Gizan in Saudi Arabia. The flow rate Q increases with the increase of pump power for different heads following the nonlinear model proposed. Keywords: Photovoltaic water pumping system, Solar radiation data, Simulation, Flow rate

  18. Role of soil characteristics on analysis of water flow in shallow land

    International Nuclear Information System (INIS)

    Tohaya, Takayuki; Wakabayashi, Noriaki; Wadachi, Yoshiki.

    1987-09-01

    Analysis of water flow on posutulated model grounds has been carried out by using 2-dimensional finite element analytical model, to clarify the effects of soil characteristics (hydroulic conductivities in saturated and unsaturated zones, moisture content - water head relationship, porosity, etc.) of a shallow land layer on variations in water tables and water flow rates. Results thus obtained indicate that hydroulic conductivities in saturated and unsaturated zones play an important role in governing the development of a water table, especially the hydroulic conductivity of the top layer and of the layers near the water table give significant effect on the water table development. It was found through multiple regression analyses of the variation of the water table that among soil characteristics following parameters give pronounced effect on the development of the water table in the order; the relationship between moisture content of the unsaturated zone and pressure head, the distance between the water table and ground surface, and the saturated hydroulic conductivity of the layer immediately above the water table. (author)

  19. South Asia river-flow projections and their implications for water resources

    Science.gov (United States)

    Mathison, C.; Wiltshire, A. J.; Falloon, P.; Challinor, A. J.

    2015-12-01

    South Asia is a region with a large and rising population, a high dependence on water intense industries, such as agriculture and a highly variable climate. In recent years, fears over the changing Asian summer monsoon (ASM) and rapidly retreating glaciers together with increasing demands for water resources have caused concern over the reliability of water resources and the potential impact on intensely irrigated crops in this region. Despite these concerns, there is a lack of climate simulations with a high enough resolution to capture the complex orography, and water resource analysis is limited by a lack of observations of the water cycle for the region. In this paper we present the first 25 km resolution regional climate projections of river flow for the South Asia region. Two global climate models (GCMs), which represent the ASM reasonably well are downscaled (1960-2100) using a regional climate model (RCM). In the absence of robust observations, ERA-Interim reanalysis is also downscaled providing a constrained estimate of the water balance for the region for comparison against the GCMs (1990-2006). The RCM river flow is routed using a river-routing model to allow analysis of present-day and future river flows through comparison with available river gauge observations. We examine how useful these simulations are for understanding potential changes in water resources for the South Asia region. In general the downscaled GCMs capture the seasonality of the river flows but overestimate the maximum river flows compared to the observations probably due to a positive rainfall bias and a lack of abstraction in the model. The simulations suggest an increasing trend in annual mean river flows for some of the river gauges in this analysis, in some cases almost doubling by the end of the century. The future maximum river-flow rates still occur during the ASM period, with a magnitude in some cases, greater than the present-day natural variability. Increases in river flow

  20. 75 FR 75761 - Water Quality Standards for the State of Florida's Lakes and Flowing Waters

    Science.gov (United States)

    2010-12-06

    ... from high levels of nitrates, possible formation of disinfection byproducts in drinking water, and... treat drinking water react with organic carbon (from the algae in source waters). Some disinfection... nitrate limit of 10 mg/L and nitrite limit of 1 mg/L for the protection of human health in drinking water...

  1. Velocity flow field and water level measurements in shoaling and breaking water waves

    CSIR Research Space (South Africa)

    Mukaro, R

    2010-01-01

    Full Text Available In this paper we report on the laboratory investigations of breaking water waves. Measurements of the water levels and instantaneous fluid velocities were conducted in water waves breaking on a sloping beach within a glass flume. Instantaneous water...

  2. Countercurrent Air-Water Flow in a Scale-Down Model of a Pressurizer Surge Line

    Directory of Open Access Journals (Sweden)

    Takashi Futatsugi

    2012-01-01

    Full Text Available Steam generated in a reactor core and water condensed in a pressurizer form a countercurrent flow in a surge line between a hot leg and the pressurizer during reflux cooling. Characteristics of countercurrent flow limitation (CCFL in a 1/10-scale model of the surge line were measured using air and water at atmospheric pressure and room temperature. The experimental results show that CCFL takes place at three different locations, that is, at the upper junction, in the surge line, and at the lower junction, and its characteristics are governed by the most dominating flow limitation among the three. Effects of inclination angle and elbows of the surge line on CCFL characteristics were also investigated experimentally. The effects of inclination angle on CCFL depend on the flow direction, that is, the effect is large for the nearly horizontal flow and small for the vertical flow at the upper junction. The presence of elbows increases the flow limitation in the surge line, whereas the flow limitations at the upper and lower junctions do not depend on the presence of elbows.

  3. Flume experiments on wind induced flow in static water bodies in the presence of protruding vegetation

    Science.gov (United States)

    Banerjee, Tirtha; Muste, Marian; Katul, Gabriel

    2015-02-01

    The problem of wind-induced flow in inland waters is drawing significant research attention given its relevance to a plethora of applications in wetlands including treatment designs, pollution reduction, and biogeochemical cycling. The present work addresses the role of wind induced turbulence and waves within an otherwise static water body in the presence of rigid and flexible emergent vegetation through flume experimentation and time series analysis. Because no prior example of Particle Imaging Velocimetry (PIV) experiments involving air-water and flexible oscillating components have been found in the literature, a spectral analysis framework is needed and proposed here to guide the analysis involving noise, wave and turbulence separation. The experiments reveal that wave and turbulence effects are simultaneously produced at the air-water interface and the nature of their coexistence is found to vary with different flow parameters including water level, mean wind speed, vegetation density and its flexibility. For deep water levels, signature of fine-scaled inertial turbulence is found at deeper layers of the water system. The wave action appears stronger close to the air-water interface and damped by the turbulence deeper inside the water system. As expected, wave action is found to be dominated in a certain frequency range driven by the wind forcing, while it is also diffused to lower frequencies by means of (wind-induced) oscillations in vegetation. Regarding the mean water velocity, existence of a counter-current flow and its switching to fully forward flow in the direction of the wind under certain combinations of flow parameters were studied. The relative importance of wave and turbulence to the overall energy, degree of anisotropy in the turbulent energy components, and turbulent momentum transport at different depths from the air-water interface and flow combinations were then quantified. The flume experiments reported here differ from previous laboratory

  4. Blue Planet dialysis: novel water-sparing strategies for reducing dialysate flow.

    Science.gov (United States)

    Molano-Triviño, Alejandra; Wancjer, Benjamin; Neri, Mauro M; Karopadi, Akash N; Rosner, Mitchell; Ronco, Claudio

    2017-11-08

    Hemodialysis (HD) is an expensive therapy in economic and in ecological terms, owing to a high carbon footprint and significant consumption of natural sources, especially water. Our aim was to review strategies to diminish waste of water in maintenance dialysis, exploring previously described water reuse trends and less known strategies for reducing the dialysate flow. We conducted a systematic review of water-sparing strategies, including the reuse of reverse osmosis rejected water and the reduction of dialysate flux. We performed a search in Medline, Pubmed, Scielo, OVID and Biblioteca Redentor, using key words: Dialysate flow rate, Dialysate flux, and decrease; excluding: online, peritoneal, continuous, blood access, needle, hemodiafiltration, acute, pharmacokinetics, increase. We limited our search to adult humans or in vitro trials in English, Spanish, Italian and Portuguese, between January 1980 and June 2017. We found 816 trials. 37 articles were retrieved for review, and 11 articles were analyzed. Conservation of water in chronic HD should be considered an important responsibility of healthcare practitioners all over the world. We present a wider usage of dialysate flow rates, considering that it would lead to significant water conservation without much compromise on dialysis efficacy in small patients. We believe that further investigation into the utility of reduced dialysate flux in different populations is needed to broaden our understanding of how we can use these techniques in order to significantly reduce water consumption during chronic HD while still ensuring optimum efficacy and efficiency of the therapy.

  5. Numerical analysis of water hammer induced by injection of subcooled water into steam flow in a horizontal pipe

    International Nuclear Information System (INIS)

    Minato, Akihiko; Nagoyoshi, Takuji; Nakamura, Akira; Fujii, Yuzo; Aya, Izuo; Yamane, Kenji

    2004-01-01

    Subcooled water injection into steam flow in piping systems may generate a water column containing a large steam slug. The steam slug collapses due to rapid condensation and interfaces on both sides collides with each other. Water hammer takes place and sharp pressure pulse propagates through the pipe. The purpose of this study is to show capability of the present numerical simulation method for predictions of pressure transient and loads on a piping system following steam slug collapse. A three-dimensional computer code for transient gas-liquid two-phase flow was applied to simulate an experiment of steam-condensation-induced water hammer with a horizontal polycarbonate pipe. The code was based on the extended two-fluid model, which treated interface motion using the VOF (Volume of Fluid) technique. The Godunov scheme of highly compressible single-phase flow was modified for application to the Riemann problem solution of gas-liquid mixture. Analysis of local steam slug collapse resulted in comparable peak pressure and pulse width of pressure transients with the observation. The calculation of pressure pulse propagation and impact load on piping system showed the quasi-steady pressure load was imposed especially on elbow at 1/10 of water hammer peak pressure. (author)

  6. Experimental and numerical characterization of the water flow in spacer-filled channels of spiral-wound membranes

    KAUST Repository

    Bucs, Szilard; Valladares Linares, Rodrigo; Marston, Jeremy O.; Radu, Andrea I.; Vrouwenvelder, Johannes S.; Picioreanu, Cristian

    2015-01-01

    Micro-scale flow distribution in spacer-filled flow channels of spiral-wound membrane modules was determined with a particle image velocimetry system (PIV), aiming to elucidate the flow behaviour in spacer-filled flow channels. Two-dimensional water

  7. Prolonged river water pollution due to variable-density flow and solute transport in the riverbed

    Science.gov (United States)

    Jin, Guangqiu; Tang, Hongwu; Li, Ling; Barry, D. A.

    2015-04-01

    A laboratory experiment and numerical modeling were used to examine effects of density gradients on hyporheic flow and solute transport under the condition of a solute pulse input to a river with regular bed forms. Relatively low-density gradients due to an initial salt pulse concentration of 1.55 kg m-3 applied in the experiment were found to modulate significantly the pore-water flow and solute transport in the riverbed. Such density gradients increased downward flow and solute transport in the riverbed by factors up to 1.6. This resulted in a 12.2% increase in the total salt transfer from the water column to the riverbed over the salt pulse period. As the solute pulse passed, the effect of the density gradients reversed, slowing down the release of the solute back to the river water by a factor of 3.7. Numerical modeling indicated that these density effects intensified as salt concentrations in the water column increased. Simulations further showed that the density gradients might even lead to unstable flow and result in solute fingers in the bed of large bed forms. The slow release of solute from the bed back to the river led to a long tail of solute concentration in the river water. These findings have implications for assessment of impact of pollution events on river systems, in particular, long-term effects on both the river water and riverbed due to the hyporheic exchange.

  8. Hydraulic Bureaucracies and the Hydraulic Mission: Flows of Water, Flows of Power

    NARCIS (Netherlands)

    Molle, F.; Mollinga, P.P.; Wester, P.

    2009-01-01

    Anchored in 19th century scientism and an ideology of the domination of nature, inspired by colonial hydraulic feats, and fuelled by technological improvements in high dam constructions and power generation and transmission, large-scale water resources development has been a defining feature of the

  9. Directions of flow of the water-bearing stratum in Friuli (NE Italy)

    Science.gov (United States)

    Cucchi, F.; Affatato, A.; Andrian, L.; Devoto, S.; Mereu, A.; Oberti, S.; Piano, C.; Rondi, V.; Zini, L.

    2003-04-01

    Flow directions of the water -- bearing stratum were executed with a Thermal Flowmeter in the Northern Friuli Plain. This type of instrument used is made up by a heater, a compass and various sensors of temperature. It is connected to an outside computer. It measures the induced thermal currents and identifies the direction and the intensity of the flow. The Thermal Flowmeter can be used in wells of little diameter and for big depths. The campaign of measures, about a hundred, confirms the general correspondence between the directions of the flows obtained from the water table and those measured through the Flowmeter in the permeable bodies with primary permeability. Different flow directions compared to the general picture were noticed in the conglomerate bodies, because of a secondary permeability. Direction changes are also noticed for the heterogeneity of the sediments which constitute the aquifer to big and to little scale.

  10. How Important Is Connectivity for Surface Water Fluxes? A Generalized Expression for Flow Through Heterogeneous Landscapes

    Science.gov (United States)

    Larsen, Laurel G.; Ma, Jie; Kaplan, David

    2017-10-01

    How important is hydrologic connectivity for surface water fluxes through heterogeneous floodplains, deltas, and wetlands? While significant for management, this question remains poorly addressed. Here we adopt spatial resistance averaging, based on channel and patch configuration metrics quantifiable from aerial imagery, to produce an upscaled rate law for discharge. Our model suggests that patch coverage largely controls discharge sensitivity, with smaller effects from channel connectivity and vegetation patch fractal dimension. However, connectivity and patch configuration become increasingly important near the percolation threshold and at low water levels. These effects can establish positive feedbacks responsible for substantial flow change in evolving landscapes (14-36%, in our Everglades case study). Connectivity also interacts with other drivers; flow through poorly connected hydroscapes is less resilient to perturbations in other drivers. Finally, we found that flow through heterogeneous patches is alone sufficient to produce non-Manning flow-depth relationships commonly observed in wetlands but previously attributed to depth-varying roughness.

  11. Water flowing north of the border: export agriculture and water politics in a rural community in Baja California.

    Science.gov (United States)

    Zlolniski, Christian

    2011-01-01

    Favored by neoliberal agrarian policies, the production of fresh crops for international markets has become a common strategy for economic development in Mexico and other Latin American countries. But as some scholars have argued, the global fresh produce industry in developing countries in which fresh crops are produced for consumer markets in affluent nations implies “virtual water flows,” the transfer of high volumes of water embedded in these crops across international borders. This article examines the local effects of the production of fresh produce in the San Quintín Valley in northwestern Mexico for markets in the United States. Although export agriculture has fostered economic growth and employment opportunities for indigenous farm laborers, it has also led to the overexploitation of underground finite water resources, and an alarming decline of the quantity and quality of water available for residents’ domestic use. I discuss how neoliberal water policies have further contributed to water inequalities along class and ethnic lines, the hardships settlers endure to secure access to water for their basic needs, and the political protests and social tensions water scarcity has triggered in the region. Although the production of fresh crops for international markets is promoted by organizations such as the World Bank and Inter-American Development Bank as a model for economic development, I argue that it often produces water insecurity for the poorest, threatening the UN goal of ensuring access to clean water as a universal human right.

  12. Influence of cold water immersion on limb and cutaneous blood flow at rest.

    Science.gov (United States)

    Gregson, Warren; Black, Mark A; Jones, Helen; Milson, Jordon; Morton, James; Dawson, Brian; Atkinson, Greg; Green, Daniel J

    2011-06-01

    Cold water immersion reduces exercise-induced muscle damage. Benefits may partly arise from a decline in limb blood flow; however, no study has comprehensively investigated the influence of different degrees of cooling undertaken via cold water immersion on limb blood flow responses. To determine the influence of cold (8°C) and cool (22°C) water immersion on lower limb and cutaneous blood flow. Controlled laboratory study. Nine men were placed in a semireclined position and lowered into 8°C or 22°C water to the iliac crest for two 5-minute periods interspersed with 2 minutes of nonimmersion. Rectal and thigh skin temperature, deep and superficial muscle temperature, heart rate, mean arterial pressure, thigh cutaneous blood velocity (laser Doppler), and superficial femoral artery blood flow (duplex ultrasound) were measured during immersion and for 30 minutes after immersion. Indices of vascular conductance were calculated (flux and blood flow/mean arterial pressure). Reductions in rectal temperature (8°C, 0.2° ± 0.1°C; 22°C, 0.1° ± 0.1°C) and thigh skin temperature (8°C, 6.2° ± 0.5°C; 22°C, 3.2° ± 0.2°C) were greater in 8°C water than in 22°C (P water compared with 22°C (P = .01). These data suggest that immersion at both temperatures resulted in similar whole limb blood flow but, paradoxically, more blood was distributed to the skin in the colder water. This suggests that colder temperatures may be associated with reduced muscle blood flow, which could provide an explanation for the benefits of cold water immersion in alleviating exercise-induced muscle damage in sports and athletic contexts. Colder water temperatures may be more effective in the treatment of exercise-induced muscle damage and injury rehabilitation because of greater reductions in muscle blood flow.

  13. Comparability of slack water and Lagrangian flow respirometry methods for community metabolic measurements.

    Directory of Open Access Journals (Sweden)

    Emily C Shaw

    Full Text Available Coral reef calcification is predicted to decline as a result of ocean acidification and other anthropogenic stressors. The majority of studies predicting declines based on in situ relationships between environmental parameters and net community calcification rate have been location-specific, preventing accurate predictions for coral reefs globally. In this study, net community calcification and production were measured on a coral reef flat at One Tree Island, Great Barrier Reef, using Lagrangian flow respirometry and slack water methods. Net community calcification, daytime net photosynthesis and nighttime respiration were higher under the flow respirometry method, likely due to increased water flow relative to the slack water method. The two methods also varied in the degrees to which they were influenced by potential measurement uncertainties. The difference in the results from these two commonly used methods implies that some of the location-specific differences in coral reef community metabolism may be due to differences in measurement methods.

  14. Two dimensional numerical model for steam--water flow in a sudden contraction

    International Nuclear Information System (INIS)

    Crowe, C.T.; Choi, H.N.

    1976-01-01

    A computational model developed for two-dimensional dispersed two-phase flows is applied to steam--water flow in a sudden contraction. The calculational scheme utilizes the cellular approach in which each cell is regarded as a control volume and the droplets are regarded as sources of mass, momentum and energy to the conveying (steam) phase. The predictions show how droplets channel in the entry region and affect the velocity and pressure distributions along the duct

  15. Interpretation of field experiments on the flow of water and tracers through crystalline rock

    International Nuclear Information System (INIS)

    Hodgkinson, D.P.; Lever, D.A.; Robinson, P.C.; Bourke, P.J.

    1983-01-01

    This paper reviews recent work at Harwell on the interpretation of field experiments on the flow of water and tracers through crystalline rock. First a model for the radial transport of tracers through an isolated fracture is outlined and used to analyse a recent Swedish experiment at Finnsjoen. Secondly, the theoretical and experimental approach that is being used to quantify flow and dispersion through networks of fractures is described

  16. The use of tracer techniques to measure water flow rates in steam turbines

    International Nuclear Information System (INIS)

    Whitfield, O.J.; Blaylock, G.; Gale, R.W.

    1979-01-01

    Radioactive and chemical tracers offer some unique advantages in detailed flow measurement on steam turbine plant. A series of experiments on a nuclear power station are reported where tracers successfully measured water flow rates and the initial steam moisture with an accuracy suitable for performance and commissioning tests. Both radioactive and chemical tracer methods produced identical results. Straightforward practical procedures were evolved that ensured repeatable accuracy and in addition a quantitative method of detecting heater leaks on load was established. (author)

  17. Experimental Investigation of the Hot Water Layer Effect on Upward Flow Open Pool Reactor Operability

    International Nuclear Information System (INIS)

    Abou Elmaaty, T.

    2014-01-01

    The open pool reactor offers a high degree of reliability in the handling and manoeuvring, the replacement of reactor internal components and the suing of vertical irradiation channels. The protection of both the operators and the reactor hall environment against radiation hazards is considered a matter of interest. So, a hot water layer is implemented above many of the research reactors main pool, especially those whose flow direction is upward flow. An experimental work was carried out to ensure the operability of the upward flow open pool research reactor with / without the hot water layer. The performed experiment showed that, the hot water layer is produced an inverse buoyant force make the water to diffuse downward against the ordinary natural circulation from the reactor core. An upward flow - open pool research reactor (with a power greater than 20 M watt) could not wok without a hot water layer. The high temperature of the hot water layer surface could release a considerable amount of water vapour into the reactor hall, so a heat and mass transfer model is built based on the measured hot water layer surface temperature to calculate the amount of released water vapour during the reactor operating period. The effects of many parameters like the ambient air temperature, the reactor hall relative humidity and the speed of the pushed air layer above the top pool end on the evaporation rate is studied. The current study showed that, the hot water layer system is considered an efficient shielding system against Gamma radiation for open pool upward flow reactor and that system should be operated before the reactor start up by a suitable period of time. While, the heat and mass transfer model results showed that, the amount of the released water vapour is increased as a result of both the increase in hot water layer surface temperature and the increase in air layer speed. As the increase in hot water layer surface temperature could produce a good operability

  18. Experimental Investigation of the Hot Water Layer Effect on Upward Flow Open Pool Reactor Operability

    International Nuclear Information System (INIS)

    Abou Elmaaty, T.

    2015-01-01

    The open pool reactor offers a high degree of reliability in the handling and manoeuvring, the replacement of reactor internal components and the swing of vertical irradiation channels. The protection of both the operators and the reactor hall environment against radiation hazards is considered a matter of interest. So, a hot water layer implemented above many of the research reactors main pool, especially those whose flow direction is upward flow. An experimental work was carried out to ensure the operability of the upward flow open pool research reactor with / without the hot water layer. The performed experiment showed that, the hot water layer produced an inverse buoyant force making the water to diffuse downward against the ordinary natural circulation from the reactor core. An upward flow-open pool research reactor (with a power greater than 20 Mw) could not wok without a hot water layer. The high temperature of the hot water layer surface could release a considerable amount of water vapour into the reactor hall, so a heat and mass transfer model is built based on the measured hot water layer surface temperature to calculate the amount of released water vapour during the reactor operating period. The effects of many parameters like the ambient air temperature, the reactor hall relative humidity and the speed of the pushed air layer above the top pool end on the evaporation rate is studied. The current study showed that, the hot water layer system is considered an efficient shielding system against gamma radiation for open pool upward flow reactor and that system should be operated before the reactor start up by a suitable period of time. While, the heat and mass transfer model results showed that, the amount of the released water vapour is increased as a result of both the increase in hot water layer surface temperature and the increase in air layer speed. As the increase in hot water layer surface temperature could produce a good operability conditions from

  19. Water Flow Testing and Unsteady Pressure Analysis of a Two-Bladed Liquid Oxidizer Pump Inducer

    Science.gov (United States)

    Schwarz, Jordan B.; Mulder, Andrew; Zoladz, Thomas

    2011-01-01

    The unsteady fluid dynamic performance of a cavitating two-bladed oxidizer turbopump inducer was characterized through sub-scale water flow testing. While testing a novel inlet duct design that included a cavitation suppression groove, unusual high-frequency pressure oscillations were observed. With potential implications for inducer blade loads, these high-frequency components were analyzed extensively in order to understand their origins and impacts to blade loading. Water flow testing provides a technique to determine pump performance without the costs and hazards associated with handling cryogenic propellants. Water has a similar density and Reynolds number to liquid oxygen. In a 70%-scale water flow test, the inducer-only pump performance was evaluated. Over a range of flow rates, the pump inlet pressure was gradually reduced, causing the flow to cavitate near the pump inducer. A nominal, smooth inducer inlet was tested, followed by an inlet duct with a circumferential groove designed to suppress cavitation. A subsequent 52%-scale water flow test in another facility evaluated the combined inducer-impeller pump performance. With the nominal inlet design, the inducer showed traditional cavitation and surge characteristics. Significant bearing loads were created by large side loads on the inducer during synchronous cavitation. The grooved inlet successfully mitigated these loads by greatly reducing synchronous cavitation, however high-frequency pressure oscillations were observed over a range of frequencies. Analytical signal processing techniques showed these oscillations to be created by a rotating, multi-celled train of pressure pulses, and subsequent CFD analysis suggested that such pulses could be created by the interaction of rotating inducer blades with fluid trapped in a cavitation suppression groove. Despite their relatively low amplitude, these high-frequency pressure oscillations posed a design concern due to their sensitivity to flow conditions and

  20. Physiological Plasticity to Water Flow Habitat in the Damselfish, Acanthochromis polyacanthus: Linking Phenotype to Performance

    Science.gov (United States)

    Binning, Sandra A.; Ros, Albert F. H.; Nusbaumer, David; Roche, Dominique G.

    2015-01-01

    The relationships among animal form, function and performance are complex, and vary across environments. Therefore, it can be difficult to identify morphological and/or physiological traits responsible for enhancing performance in a given habitat. In fishes, differences in swimming performance across water flow gradients are related to morphological variation among and within species. However, physiological traits related to performance have been less well studied. We experimentally reared juvenile damselfish, Acanthochromis polyacanthus, under different water flow regimes to test 1) whether aspects of swimming physiology and morphology show plastic responses to water flow, 2) whether trait divergence correlates with swimming performance and 3) whether flow environment relates to performance differences observed in wild fish. We found that maximum metabolic rate, aerobic scope and blood haematocrit were higher in wave-reared fish compared to fish reared in low water flow. However, pectoral fin shape, which tends to correlate with sustained swimming performance, did not differ between rearing treatments or collection sites. Maximum metabolic rate was the best overall predictor of individual swimming performance; fin shape and fish total length were 3.3 and 3.7 times less likely than maximum metabolic rate to explain differences in critical swimming speed. Performance differences induced in fish reared in different flow environments were less pronounced than in wild fish but similar in direction. Our results suggest that exposure to water motion induces plastic physiological changes which enhance swimming performance in A. polyacanthus. Thus, functional relationships between fish morphology and performance across flow habitats should also consider differences in physiology. PMID:25807560

  1. Environmental Flows in Water Resources Policies, Plans, and Projects - Part 1: Findings and Recommendations and Part 2: Case Studies

    OpenAIRE

    World Bank

    2010-01-01

    Environmental flows are central to equitable distribution of and access to water and services provided by aquatic ecosystems. They refer to the quality, quantity, and timing of water flows required maintaining the components, functions, processes and resilience of aquatic ecosystems that provide goods and services to people. They are fundamental for sustainable water resources development, ...

  2. Effects of historic forest disturbance on water quality and flow in the Interior Western U.S

    Science.gov (United States)

    M. Matyjasik; G. Moisen; C. Combe; T. Hathcock; S. Mitts; M. Hernandez; T. Frescino; T. Schroeder

    2014-01-01

    Water quality and flow is affected my many complex factors in the Interior Western U.S. While many studies focus on individual water parameters response to a limited number of changing conditions, little work looks at long term effects of diverse forest disturbances on a broader array of water quality and flow metrics. The U.S. Forest Service Forest Inventory and...

  3. Radionuclide transfer onto ground surface in surface water flow. 2. Undisturbed tuff rock

    International Nuclear Information System (INIS)

    Mukai, Masayuki; Takebe, Shinichi; Komiya, Tomokazu

    1994-09-01

    Radionuclide migration with ground surface water flow is considered to be one of path ways in the scenario for environmental migration of the radionuclide leaked from LLRW depository. To study the radionuclide migration demonstratively, a ground surface radionuclide migration test was carried out by simulating radioactive solution flowing on the sloped tuff rock surface. Tuff rock sample of 240 cm in length taken from the Shimokita district was used to test the transfer of 60 Co, 85 Sr and 137 Cs onto the sample surface from the flowing radioactive solution under restricted infiltration condition at flow rates of 25, 80, 160ml/min and duration of 56h. The concentration change of the radionuclides in effluent was nearly constant as a function of elapsed time during the experimental period, but decreased with lower flow rates. Among the three radionuclides, 137 Cs was greatly decreased its concentration to 30% of the inflow. Adsorbed distribution of the radionuclides concentration on the ground surface decreased gradually with the distance from the inlet, and showed greater gradient at lower flow rate. Analyzing the result by the migration model, where a vertical advection distribution and two-dimensional diffusion in surface water are adopted with a first order adsorption reaction, value of migration parameters was obtained relating to the radionuclide adsorption and the surface water flow, and the measured distribution could be well simulated by adopting the value to the model. By comparing the values with the case of loamy soil layer, all values of the migration parameters showed not so great difference between two samples for 60 Co and 85 Sr. For 137 Cs, reflecting a few larger value of adsorption to the tuff rock, larger ability to reduce the concentration of flowing radioactive solution could be indicated than that to the loamy soil surface by estimation for long flowed distance. (author)

  4. Flow splitting in numerical simulations of oceanic dense-water outflows

    Science.gov (United States)

    Marques, Gustavo M.; Wells, Mathew G.; Padman, Laurie; Özgökmen, Tamay M.

    2017-05-01

    Flow splitting occurs when part of a gravity current becomes neutrally buoyant and separates from the bottom-trapped plume as an interflow. This phenomenon has been previously observed in laboratory experiments, small-scale water bodies (e.g., lakes) and numerical studies of small-scale systems. Here, the potential for flow splitting in oceanic gravity currents is investigated using high-resolution (Δx = Δz = 5 m) two-dimensional numerical simulations of gravity flows into linearly stratified environments. The model is configured to solve the non-hydrostatic Boussinesq equations without rotation. A set of experiments is conducted by varying the initial buoyancy number B0 =Q0N3 /g‧2 (where Q0 is the volume flux of the dense water flow per unit width, N is the ambient stratification and g‧ is the reduced gravity), the bottom slope (α) and the turbulent Prandtl number (Pr). Regardless of α or Pr, when B0 ≤ 0.002 the outflow always reaches the deep ocean forming an underflow. Similarly, when B0 ≥ 0.13 the outflow always equilibrates at intermediate depths, forming an interflow. However, when B0 ∼ 0.016, flow splitting always occurs when Pr ≥ 10, while interflows always occur for Pr = 1. An important characteristic of simulations that result in flow splitting is the development of Holmboe-like interfacial instabilities and flow transition from a supercritical condition, where the Froude number (Fr) is greater than one, to a slower and more uniform subcritical condition (Fr internal hydraulic jump and consequent mixing enhancement. Although our experiments do not take into account three-dimensionality and rotation, which are likely to influence mixing and the transition between flow regimes, a comparison between our results and oceanic observations suggests that flow splitting may occur in dense-water outflows with weak ambient stratification, such as Antarctic outflows.

  5. Role of mixed boundaries on flow in open capillary channels with curved air-water interfaces.

    Science.gov (United States)

    Zheng, Wenjuan; Wang, Lian-Ping; Or, Dani; Lazouskaya, Volha; Jin, Yan

    2012-09-04

    Flow in unsaturated porous media or in engineered microfluidic systems is dominated by capillary and viscous forces. Consequently, flow regimes may differ markedly from conventional flows, reflecting strong interfacial influences on small bodies of flowing liquids. In this work, we visualized liquid transport patterns in open capillary channels with a range of opening sizes from 0.6 to 5.0 mm using laser scanning confocal microscopy combined with fluorescent latex particles (1.0 μm) as tracers at a mean velocity of ∼0.50 mm s(-1). The observed velocity profiles indicate limited mobility at the air-water interface. The application of the Stokes equation with mixed boundary conditions (i.e., no slip on the channel walls and partial slip or shear stress at the air-water interface) clearly illustrates the increasing importance of interfacial shear stress with decreasing channel size. Interfacial shear stress emerges from the velocity gradient from the adjoining no-slip walls to the center where flow is trapped in a region in which capillary forces dominate. In addition, the increased contribution of capillary forces (relative to viscous forces) to flow on the microscale leads to increased interfacial curvature, which, together with interfacial shear stress, affects the velocity distribution and flow pattern (e.g., reverse flow in the contact line region). We found that partial slip, rather than the commonly used stress-free condition, provided a more accurate description of the boundary condition at the confined air-water interface, reflecting the key role that surface/interface effects play in controlling flow behavior on the nanoscale and microscale.

  6. Multivariate weighted recurrence network inference for uncovering oil-water transitional flow behavior in a vertical pipe.

    Science.gov (United States)

    Gao, Zhong-Ke; Yang, Yu-Xuan; Cai, Qing; Zhang, Shan-Shan; Jin, Ning-De

    2016-06-01

    Exploring the dynamical behaviors of high water cut and low velocity oil-water flows remains a contemporary and challenging problem of significant importance. This challenge stimulates us to design a high-speed cycle motivation conductance sensor to capture spatial local flow information. We systematically carry out experiments and acquire the multi-channel measurements from different oil-water flow patterns. Then we develop a novel multivariate weighted recurrence network for uncovering the flow behaviors from multi-channel measurements. In particular, we exploit graph energy and weighted clustering coefficient in combination with multivariate time-frequency analysis to characterize the derived complex networks. The results indicate that the network measures are very sensitive to the flow transitions and allow uncovering local dynamical behaviors associated with water cut and flow velocity. These properties render our method particularly useful for quantitatively characterizing dynamical behaviors governing the transition and evolution of different oil-water flow patterns.

  7. Flow friction and heat transfer of ethanol–water solutions through silicon microchannels

    International Nuclear Information System (INIS)

    Wu Huiying; Wu Xinyu; Wei Zhen

    2009-01-01

    An experimental investigation was performed on the flow friction and convective heat transfer characteristics of the ethanol–water solutions flowing through five sets of trapezoidal silicon microchannels having hydraulic diameters ranging from 141.7 µm to 268.6 µm. Four kinds of ethanol–water solutions with the ethanol volume concentrations ranging from 0 to 0.8 were tested under different flow and heating conditions. It was found that the cross-sectional geometric parameters had great effect on the flow friction and heat transfer, and the microchannels with a larger W b /W t (bottom width-to-top width ratio) and a smaller H/W t (depth-to-top width ratio) usually had a larger friction constant and a higher Nusselt number. Entrance effects were significant for the flow friction and heat transfer in silicon microchannels, and decreased with the increase of dimensionless hydrodynamic length L and dimensionless thermal length L + h . When L > 1.0, the hydrodynamic entrance effect on the flow friction was ignorable. For the developed laminar flow in silicon microchannels, the Navier–Stokes equation was applicable. It was also found that the volume concentrations had different effects on the flow friction and heat transfer. Within the experimental range, the effect of volume concentrations on the flow friction was ignorable, and the friction constants of the ethanol–water solutions having different concentrations were the same as those of the pure water. However, volume concentrations had great effect on the convection heat transfer in silicon microchannels. With the increase of the volume concentrations, the Nusselt number of the ethanol–water solutions increased obviously, which was attributed to the combination effect of the increase in the Prantdtl number as well as the volatilization effect of the ethanol. Based on the experimental data, the dimensionless correlations for the flow friction and heat transfer of the ethanol–water solutions in the silicon

  8. Modeling of cavitation in sodium flow by water flow test in prototypical LMFBR components

    International Nuclear Information System (INIS)

    Soehendro, B.; Trejo, F.; Bonilla, C.F.

    1976-02-01

    Cavitation tests of water recirculating through a venturi or a rounded inlet nozzle were carried out under steady conditions. Water temperature was varied from 100 to 195 0 F. Argon was used as cover gas and to regulate pressure in the loop. Cavitation was detected by the voltage output of a piezo-electric lead-zirconate-titanate ceramic on a titanium alloy horn facing the cavitator outlet. Three different incipient and desinent cavitation modes, designated gaseous, gaseous-vaporous, and vaporous were observed, and no significant difference was found between the conditions for incipient and desinent cavitation. Local cavitation number and fraction of equilibrium argon pressure in the gas phase at incipient and desinent cavitation are almost constant in the ranges of temperature and argon content studied. Injection of gas into the stream does not change the conditions for vaporous cavitation, but affects the gaseous and gaseous-vaporous cavitation considerably

  9. Determination of flow rates of oil, water and gas in pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Roach, G J; Watt, J S; Zastawny, H W [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lucas Heights, NSW (Australia). Div. of Mineral Physics

    1994-12-31

    This paper describes a multiphase flow meter developed by CSIRO for determining of the flow rates of oil, water and gas in high pressure pipelines, and the results of a trial of this flow meter on an offshore oil platform. Two gamma-ray transmission gauges are mounted about a pipeline carrying the full flow of oil, water and gas. The flow rates are determined by combining single energy gamma-ray transmission measurements which determine the mass per unit area of fluids in the gamma-ray beam as a function of time, dual energy gamma-ray transmission (DUET) which determine the approximate mass fraction of oil in the liquids, cross-correlation of gamma-ray transmission measurements, with one gauge upstream of the other, which determines flow velocity, pressure and temperature measurements, and knowledge of the specific gravities of oil and (salt) water, and solubility of the gas in the liquids, all as a function of pressure and temperature. 3 figs.

  10. Determination of flow rates of oil, water and gas in pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Roach, G.J.; Watt, J.S.; Zastawny, H.W. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lucas Heights, NSW (Australia). Div. of Mineral Physics

    1993-12-31

    This paper describes a multiphase flow meter developed by CSIRO for determining of the flow rates of oil, water and gas in high pressure pipelines, and the results of a trial of this flow meter on an offshore oil platform. Two gamma-ray transmission gauges are mounted about a pipeline carrying the full flow of oil, water and gas. The flow rates are determined by combining single energy gamma-ray transmission measurements which determine the mass per unit area of fluids in the gamma-ray beam as a function of time, dual energy gamma-ray transmission (DUET) which determine the approximate mass fraction of oil in the liquids, cross-correlation of gamma-ray transmission measurements, with one gauge upstream of the other, which determines flow velocity, pressure and temperature measurements, and knowledge of the specific gravities of oil and (salt) water, and solubility of the gas in the liquids, all as a function of pressure and temperature. 3 figs.

  11. Second status report on regional ground-water flow modeling for the Palo Duro Basin, Texas

    International Nuclear Information System (INIS)

    1986-07-01

    Regional ground-water flow within the principal geohydrologic units of the Palo Duro Basin is evaluated by developing a conceptual model of the flow regime and testing the model using a three-dimensional, finite-difference flow code. Sensitivity analyses (a limited parametric study) are conducted to define the system responses to changes in the conceptual model. Of particular interest are the impacts of salt permeability and potential climatic changes on the system response. The conceptual model is described in terms of its areal and vertical discretization, aquifer properties, fluid properties and hydrologic boundary conditions. The simulated ground-water flow fields are described with potentiometric surfaces, tables summarizing the areal and vertical volumetric flows through the principal units, and Darcy velocities within specified finite-difference blocks. The reported work is the second stage of an ongoing evaluation of the Palo Duro Basin as a potential repository for high-level radioactive wastes. The results and conclusions should thus be considered preliminary and subject to modification with the collection of additional data. However, the report does provide a useful basis for describing the sensitivity of the present conceptualization of ground-water flow to particular parameters and, to a lesser extent, the uncertainties in the present conceptualization. 28 refs., 44 figs., 13 tabs

  12. Determination of flow rates of oil, water and gas in pipelines

    International Nuclear Information System (INIS)

    Roach, G.J.; Watt, J.S.; Zastawny, H.W.

    1993-01-01

    This paper describes a multiphase flow meter developed by CSIRO for determining of the flow rates of oil, water and gas in high pressure pipelines, and the results of a trial of this flow meter on an offshore oil platform. Two gamma-ray transmission gauges are mounted about a pipeline carrying the full flow of oil, water and gas. The flow rates are determined by combining single energy gamma-ray transmission measurements which determine the mass per unit area of fluids in the gamma-ray beam as a function of time, dual energy gamma-ray transmission (DUET) which determine the approximate mass fraction of oil in the liquids, cross-correlation of gamma-ray transmission measurements, with one gauge upstream of the other, which determines flow velocity, pressure and temperature measurement