WorldWideScience

Sample records for breakwaters

  1. Reshaping Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Frigaard, Peter

    1987-01-01

    The paper deals with the 3-dimensional stability of the type of rubble mound breakwaters where reshaping of the mound due to wave action is foreseen in the design. Such breakwaters are commonly named sacrificial types and berm types. The latter is due to the relatively large volume of armoure...... stones placed in a seaward berm. However, as also conventional armoured breakwaters sometimes do contain a berm it is assumed that a better and more ambiguous designation would be "reshaping" rubble mound breakwaters. The stability of a reshaping type breakwater was tested in a 3-dimensional model...... at The Hydraulics Laboratory, Department of Civil Engineering, University of Aalborg. The object was to study the stability/erosion of the breakwater head and the trunk, the latter exposed to both head-on and oblique irregular waves. To avoid too many parameters a simple breakwater geometry and only one class...

  2. The Design Of Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans F.

    1994-01-01

    The main purpose of a breakwater is to reduce the waves in an area. More often than not the objectives are to obtain acceptable mooring and manoeuvring conditions for ships, but breakwaters are also used for beach protection. Moreover, many of the principles related to the design of breakwaters a...

  3. Design of the Ciervana Breakwater

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Frigaard, Peter; Uzcanga, J.;

    1995-01-01

    A major expansion of Port Bilbao includes some 4.5 km of breakwaters in water depths up to 28 metres. Construction cost is approximately 190 mill. USD. The paper presents the lay-out and the cross section of the most exposed breakwater section.......A major expansion of Port Bilbao includes some 4.5 km of breakwaters in water depths up to 28 metres. Construction cost is approximately 190 mill. USD. The paper presents the lay-out and the cross section of the most exposed breakwater section....

  4. Scour and its protection at breakwaters

    DEFF Research Database (Denmark)

    Sumer, B. Mutlu; Fredsøe, Jørgen

    1999-01-01

    Work on scour around breakwaters (both vertical-wall breakwaters and rubble-mound breakwaters) has been described. Both 2-D scour at the trunk section of a breakwater, and 3-D scour at the head have been considered. Mechanisms responsible for the scour processes have been recapitulated, and count...

  5. Analysis of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Mettam, J.D.; Allsop, N.W.H.; Bonafous, P.;

    Working Group 12 was set up to consider the analysis of rubble mound breakwaters with a view to achieving a better understanding of safety aspects. The working group decided to develop the practical application of risk analysis in the design of rubble mound breakwaters by using partial coefficien...

  6. Rubble Mound Breakwater Failure Modes

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Z., Liu

    1995-01-01

    The RMBFM-Project (Rubble Mound Breakwater Failure Modes) is sponsored by the Directorate General XII of the Commission of the European Communities under the Contract MAS-CT92- 0042, with the objective of contributing to the development of rational methods for the design of rubble mound breakwaters...... modes, plus development of related partial coefficients which make it possible to design according to preselected reliability levels. Due to limited space only the major activities are described....

  7. Reliability Analysis of Existing Vertical Wall Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Sørensen, John Dalsgaard

    1998-01-01

    Vertical wall breakwaters are used under quite different conditions where failure of the breakwater or a part of it will have very different consequences. Further a number of existing vertical wall breakwaters have been subjected to significant wave loads which have caused partial failures of the...... of the structures. The main objective of this paper is to describe how the reliability of existing breakwater structures within the expected remaining lifetime can be estimated taking into account the available information....

  8. The Lessons From Recent Breakwater Failures

    DEFF Research Database (Denmark)

    Burcharth, Hans F.

    The design and construction of breakwaters is a classical task in coastal engineering. Breakwaters have been built, damaged and repaired for hundred of years. It is generally believed that coastal engineering science has improved a lot during the last 20 years. The profession was therefore taken...... by surprise when a series of major breakwater failures occurred very recently in a four year period....

  9. Optimum Safety Levels for Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Sørensen, John Dalsgaard

    2005-01-01

    Optimum design safety levels for rock and cube armoured rubble mound breakwaters without superstructure are investigated by numerical simulations on the basis of minimization of the total costs over the service life of the structure, taking into account typical uncertainties related to wave...... statistics and structure response. The study comprises the influence of interest rate, service lifetime, downtime costs and damage accumulation. Design limit states and safety classes for breakwaters are discussed. The results indicate that optimum safety levels are somewhat higher than the safety levels...

  10. Design of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, H. F.

    1994-01-01

    Rubble mound breakwaters require availability of often very large quantities of rock materials of various gradings and qualities. Because natural stones are seldom available in sufficient quantities and sizes the materials must in most cases be supplied from quarries. The output from a quarry...

  11. The Lessons From Recent Breakwater Failures:developments in breakwater design

    OpenAIRE

    Burcharth, Hans F.

    1987-01-01

    The design and construction of breakwaters is a classical task in coastal engineering. Breakwaters have been built, damaged and repaired for hundred of years. It is generally believed that coastal engineering science has improved a lot during the last 20 years. The profession was therefore taken by surprise when a series of major breakwater failures occurred very recently in a four year period.

  12. Flow in and on the Zeebrugge breakwater

    DEFF Research Database (Denmark)

    Schlütter, Flemming; Frigaard, Peter; Eelen, Bart;

    1996-01-01

    The paper is based on data and results obtained during the MAST ll project entitled "Full Scale Dynamic Load Monitoring of Rubble Mound Breakwaters". The main part of this project has been exploitation of a fully instrumented rubble mound breakwaters located in the outer harbour of Zeebrugge, Bel......, Belgium and conduction of attaining physical model tests at three different scales. This approach of looking into the hydraulic response of a rubble mound breakwater makes the project unique world-wide....

  13. Breakwater for the Port of Dande, Angola

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Burcharth, Hans F.; Francesco, Comola

    This report deals with a 3-D model test study of the new breakwater at Porto de Dande, Angola. Part of the trunk and the roundhead were tested in 3-D for stability, overtopping and run-up under various sea conditions. The model testing of the breakwater in a 3-D basin was requested for some relev...

  14. The PIANC Safety Factor System for Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, H. F.

    2000-01-01

    The paper presents a summary of the recommendations for implementation of safety in breakwater designs given by the PIANC PTC IT Working Group No 12 on Analysis of Rubble Mound Breakwaters with Vertical and Inclined Concrete Walls. The working groups developed for the most important failure modes...... a system of partial safety factors which facilitate design to any target safety level....

  15. Design of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, H. F.

    1992-01-01

    Rubble mound breakwaters require availability of often very large quantities of rock materials of various gradings and qualities. Because natural stones are seldom available in sufficient quantities and sizes the materials must in most cases be supplied from quarries. The output from a quarry...... the construction stage. Anyway, it is seldom that a fair amount of rocks of mass larger than 10-15 t can be produced, even in good quality quarries. If heavier blocks are needed concrete armour units or vertical structures must be considered....

  16. Safety Aspects for Vertical Wall Breakwaters

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Burcharth, H. F.; Christiani, E.

    1996-01-01

    In this appendix some safety aspects in relation to vertical wall breakwaters are discussed. Breakwater structures such as vertical wall breakwaters are used under quite different conditions. The expected lifetime can be from 5 years (interim structure) to 100 years (permanent structure) and the ......In this appendix some safety aspects in relation to vertical wall breakwaters are discussed. Breakwater structures such as vertical wall breakwaters are used under quite different conditions. The expected lifetime can be from 5 years (interim structure) to 100 years (permanent structure......) and the accepted level of probability of failure in the expected lifetime can vary from a very small number, e.g. 10-4 if failure of the breakwater results in significant damage to large probabilities, e.g. 0.5 if the consequences are insignificant. This has to be taken into account when discussing safety aspects...... and possible level I and D code formats. In the following first the most important failure modes are briefly described, see section 2. It is assumed that the failure modes can be modelled by limit state functions. Wave load models are described in section 3. In section 5 uncertainties related to the parameters...

  17. Innovative Breakwaters Design for Wave Energy Conversion

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Stagonas, D.; Müller, G.;

    2012-01-01

    the rubble mound breakwaters and seawalls related activity and the energy demand of small human communities. Wave loadings and overtopping on a seawall and rubble mound breakwater with front reservoir are discussed on the basis of physical 2-D model tests carried out at University of Southampton (UK......This paper intends contributing to an economically and environmentally sustainable development of coastal infrastructures by investigating the possibility of combining together breakwaters and Wave Energy Converters (WEC). The latter change the wave energy to electricity, which may serve both...

  18. Introduction to Coastal Engineering and Breakwaters

    NARCIS (Netherlands)

    Bijker, E.W.

    1972-01-01

    Collegedictaat f11a and f11b. Lecture notes, short waves, waves near shoreline, coastal formation, sediment transport by waves, coastal protection, delta coasts, muddy coasts, tidal rivers, density currents, breakwater design.

  19. Application of Reliability in Breakwater Design

    DEFF Research Database (Denmark)

    Christiani, Erik

    response, but in one area information has been lacking; bearing capacity has not been treated in depth in a probabilistic manner for breakwaters. Reliability analysis of conventional rubble mound breakwaters and conventional vertical breakwaters is exemplified for the purpose of establishing new ways...... by Bologna University. Thereafter a multiple system of failure for the interaction is established. Relevant stochastic parameters are characterized prior to the reliability evaluation. Application of reliability in crown wall design is illustrated by deriving relevant single foundation failure modes...... methods to design certain types of breakwaters. Reliability analyses of the main armour and toe berm interaction is exemplified to show the effect of a multiple set of failure mechanisms. First the limit state equations of the main armour and toe interaction are derived from laboratory tests performed...

  20. On Front Slope Stability of Berm Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans F.

    2013-01-01

    The short communication presents application of the conventional Van der Meer stability formula for low-crested breakwaters for the prediction of front slope erosion of statically stable berm breakwaters with relatively high berms. The method is verified (Burcharth, 2008) by comparison with the r......The short communication presents application of the conventional Van der Meer stability formula for low-crested breakwaters for the prediction of front slope erosion of statically stable berm breakwaters with relatively high berms. The method is verified (Burcharth, 2008) by comparison...... test results including tests presented in Sigurdarson and Van der Meer (2011) are discussed. A proposal is presented for performance of new model tests with the purpose of developing more accurate formulae for the prediction of front slope erosion as a function of front slope, relative berm height...

  1. Stability of Reshaping Breakwaters with Special Reference to Stone Durability

    DEFF Research Database (Denmark)

    Frigaard, Peter; Hald, Tue; Burcharth, H. F.;

    1998-01-01

    Traditionally, conventional rubble mound breakwaters are designed with stable armour units, and consequently, very large stones or even artificial armour units are required. reshaping breakwater designs allow reshaping of the seaward slope thus involving stone movements. Ultimately, dependent...

  2. Stability prediction of berm breakwater using neural network

    Digital Repository Service at National Institute of Oceanography (India)

    Mandal, S.; Rao, S.; Manjunath, Y.R.

    In the present study, an artificial neural network method has been applied to predict the stability of berm breakwaters. Four neural network models are constructed based on the parameters which influence the stability of breakwater. Training...

  3. Choice of Breakwater Type and Optimum Safety Levels

    DEFF Research Database (Denmark)

    Burcharth, Hans F.

    2009-01-01

    Breakwaters belong generally to the more expensive part of port and coastal protection structures. The fact that the main function of breakwaters is to provide shelter for wave action defines automatically the two main problems related to breakwater engineering, namely construction in often very ...

  4. Reliability Analysis of Geotechnical Failure Modes for Vertical Wall Breakwaters

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Burcharth, H. F.

    2000-01-01

    Vertical wall breakwaters are usually designed as concrete caissons placed on the top of a rubble mound foundation or a rubble bedding layer. The purpose of the breakwater is usually to protect the area behind the breakwater from being flooded by large waves. The area protected can for example...

  5. Choise of Breakwater Type and Optimum Safety Levels

    DEFF Research Database (Denmark)

    Burcharth, Hans F.

    2010-01-01

    Breakwaters belong generally to the more expensive part of port and coastal protection structures. The fact that the main function of breakwaters is to provide shelter for wave action defines automatically the two main problems related to breakwater engineering, namely construction in often very ...

  6. Numerical wave interaction with tetrapods breakwater

    Science.gov (United States)

    Dentale, Fabio; Donnarumma, Giovanna; Carratelli, Eugenio Pugliese

    2014-12-01

    The paper provides some results of a new procedure to analyze the hydrodynamic aspects of the interactions between maritime emerged breakwaters and waves by integrating CAD and CFD. The structure is modeled in the numerical domain by overlapping individual three-dimensional elements (Tetrapods), very much like the real world or physical laboratory testing. Flow of the fluid within the interstices among concrete blocks is evaluated by integrating the RANS equations. The aim is to investigate the reliability of this approach as a design tool. Therefore, for the results' validation, the numerical run-up and reflection effects on virtual breakwater were compared with some empirical formulae and some similar laboratory tests. Here are presented the results of a first simple validation procedure. The validation shows that, at present, this innovative approach can be used in the breakwater design phase for comparison between several design solutions with a significant minor cost.

  7. Stability of Hardly Reshaping Berm Breakwaters

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Van der Meer, Jentsje W.; Burcharth, Hans F.;

    2012-01-01

    in the surging wave area. Moreover, a simple method to estimate the erosion area based on recession formulae and the depth of intersection of reshaped and initial profile is presented and is applicable for hardly reshaping to fully reshaping. Even when using the only very simple and inaccurate estimate...... of the depth of intersection the last method leads to scatter quite similar to the first method when considering hardly and partly reshaping berm breakwaters. The influence of the slope angle is though expected to be more correctly included for hardly reshaping breakwaters using the method for straight non...

  8. Wave transmission by suspended pipe breakwater

    Digital Repository Service at National Institute of Oceanography (India)

    Mani, J.S.; Jayakumar, S.

    ratio of 0.46), a 5% reduction in incident-wave height can be achieved. The cost and performance of conventionally adopted pile breakwater (involving a row of closely spaced piles driven on the seabed) were compared with the present system...

  9. On Optimum Safety Levels of Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Sørensen, John Dalsgaard

    2006-01-01

    The paper presents results from numerical simulations performed with the objective of identifying optimum design safety levels of conventional rubble mound and caisson breakwaters, corresponding to the lowest costs over the service life of the structures. The work is related to the PIANC Working...

  10. Stability of Hardly Reshaping Berm Breakwaters

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; W. van der Meer, Jentsje; Burcharth, Hans F.;

    2012-01-01

    Stability of berm breakwaters has been dealt with by several authors like Van der Meer (1992) and Lykke Andersen & Burcharth (2010). The work of Van der Meer (1992) gives a very good estimate of the full reshaped profile for dynamically stable structures with a stability number Hs/ΔDn50 > 3 . How...

  11. Hydraulic Response of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke

    Rubble mound breakwaters have been extensively investigated in the last decades. Nevertheless, there still exists some white spots where only little knowledge and only poor design rules are available. Some of these white spots are due to new types of structures developed in recent years. In this ...

  12. 2-D Model Test of Dolosse Breakwater

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Liu, Zhou

    1994-01-01

    The rational design diagram for Dolos armour should incorporate both the hydraulic stability and the structural integrity. The previous tests performed by Aalborg University (AU) made available such design diagram for the trunk of Dolos breakwater without superstructures (Burcharth et al. 1992...

  13. Stresses in Dolos Breakwater Armour Units

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Liu, Z.

    1991-01-01

    Breakage of slender unreinforced armour unite is the cause of many breakwater failures. Design diagrams to ensure structural integrity of armour unite such as dolosse and tetrapods have not been available. The article presents results of an analysis of the stresses in dolosse based on model tests...

  14. Toe rock stability for rubble mound breakwaters

    NARCIS (Netherlands)

    Baart, S.; Ebbens, R.; Nammuni-Krohn, J.; Verhagen, H.J.

    2010-01-01

    Present design tools, as found in the Rock Manual or Coastal Engineering Manual, for the determination of toe rock size for rubble mound breakwaters are based on test data with a large spread: data is relatively dispersed around the centre and descriptive equations have limited applicability ranges.

  15. Reliability Index of Caisson Breakwaters for Load Variables Correlated

    Institute of Scientific and Technical Information of China (English)

    郄禄文; 李炎保

    2004-01-01

    In order to suit the condition that the wave uplift is correlated with the horizontal wave load acting on a vertical breakwater, a generally used method for determining the reliability index β of the breakwater, i.e. the Hasofer-Lind method, is extended in a generalized stochastic space for correlative variables. The computational results for a caisson breakwater indicate that the value of β for the case of correlated variables is obviously smaller than that for the case of independent variables.

  16. Toe rock stability for rubble mound breakwaters

    OpenAIRE

    Baart, S.; Ebbens, R.; Nammuni-Krohn, J.; Verhagen, H.J.

    2010-01-01

    Present design tools, as found in the Rock Manual or Coastal Engineering Manual, for the determination of toe rock size for rubble mound breakwaters are based on test data with a large spread: data is relatively dispersed around the centre and descriptive equations have limited applicability ranges. New research has been undertaken to contribute to a more accurate description of toe rock stability. Flume tests have lead to an empirical design criterion for toe bunds in very shallow water base...

  17. State-of-the-Art of Designing and Constructing Berm Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans Falk; Hedar, P. A.; Ouemeraci, H.;

    Berm breakwaters are different from ordinary rubble mound breakwaters. A conventional rubble mound breakwater is required to be almost statically stable for the design wave conditions, while the berm breakwater has traditionally been allowed to reshape to a statically stable or a dynamically stab...

  18. Scour at the head of a vertical-wall breakwater

    DEFF Research Database (Denmark)

    Sumer, B. Mutlu; Fredsøe, Jørgen

    1997-01-01

    This paper presents the results of an experimental investigation on the near-bed flow patterns, the bed shear stress amplification and scour around the head of a vertical-wall breakwater, using regular waves. The Keulegan-Carpenter number (KC), based on the diameter of the breakwater head, is fou...

  19. Innovative rubble mound breakwaters for wave energy conversion

    International Nuclear Information System (INIS)

    This paper presents a new Wave Energy Converter named Overtopping BReakwater for Energy Conversion (OBREC) which consists of a rubble mound breakwater with a front reservoir designed with the aim of capturing the wave overtopping in order to produce electricity. The energy is extracted via low head turbines, using the difference in water levels between the reservoir and the mean sea water level. The new design should be capable of adding a revenue generation function to a breakwater while adding cost sharing benefits due to integration. The design can be applied to harbour expansions, existing breakwater maintenance or upgrades due to climate change for a relatively low cost, considering the breakwater would be built regardless of the inclusion of a WEC

  20. Proposal of honeycomb-based deployable breakwater

    Science.gov (United States)

    Asanuma, H.; Okabe, S.

    2016-04-01

    This paper describes development of a smart breakwater or river bank using honeycomb-like structure to be adaptive to change of water level. A designed cell is deformed using a tensile test machine, and the results show that the honeycomb cell can deploy up to double of is original height without plastic deformation and the deformation is reproducible. It is stacked up to twelve layers and similar performance can be found. In addition, a six-layer and double-row deployable model is prepared and it became clear that the model can change its height in proportion to the water height in the experimental range and successfully block the water.

  1. Fatigue in Breakwater Concrete Armour Units

    DEFF Research Database (Denmark)

    Burcharth, Hans F.

    1985-01-01

    The reliability of rubble mound breakwaters depends on the hydraulic stability and the mechanical strength of the armour units. The paper deals with the important aspect of fatigue related to the strength of concrete armour units. Results showing significant fatigue from impact tests with Dolosse...... made of unreinforced and steel fibre reinforced flyash concrete are presented. Moreover universal graphs for fatigue in armour units made of conventional unreinforced concrete exposed to impact load and pulsating load are presented. The effect of fibre reinforcement and the implementation of fatigue in...

  2. Structural Stability of Low-Crested Breakwaters

    DEFF Research Database (Denmark)

    Kramer, Morten

    equations. New improved design formulae for calculation of static stability of LCS's are developed on the basis of new 2D and 3D laboratory experiments with scale models. The formulae are specially designed for breakwaters subject to shallow water waves and/or depth limited waves, as the majority...... of existing LCS’s are exposed to such conditions. The formulae are validated against prototype experience. Ecological aspects in relation to structural stability are important, and design guidance on how to consider ecology in the design is therefore given. The new design guidance adds practical and helpful...

  3. Experimental Investigation on Caisson Breakwater Sliding

    DEFF Research Database (Denmark)

    Ruol, Piero; Martin, Paolo; Andersen, Thomas Lykke;

    2014-01-01

    This note presents wave flume experiments, carried out at Aalborg University, measuring the horizontal sliding distance of a vertical breakwater in 1:40 scale. Horizontal and uplift wave induced pressures were accurately measured simultaneously with the caisson movements. Caissons of different...... weight and same geometries are tested under regular and irregular waves. It is found that, under breaking conditions, the expected inaccuracy of the prediction of the force, inherent on the variability of the breaking process, induce unacceptable errors in the prediction of the sliding. This observation...

  4. Hydrodynamic Behavior of Curtainwall-Pile Breakwaters

    Institute of Scientific and Technical Information of China (English)

    O.Nejadkazem; A.R.M.Gharabaghi

    2012-01-01

    A numerical model is developed that can predict the interaction of regular waves normally incident upon a curtainwall-pile breakwater; the upper part of which is a vertical wall and the lower part consists of an array of vertical piles.The numerical model is based on an eigenfunetion expansion method,and utilizes a boundary condition nearby the vertical piles that accounts for wave energy dissipation.Numerical solution comprises a finite number of terms,which is a superposition of propagating waves and a series of evanescent waves.The modeling is validated by comparison with previous experimental studies and overall agreement between measurement and calculation is fairly good.The numerical results are related to reflection,transmission,and dissipation coefficient; wave run-up,wave force,and wave overturning moment are also presented.Effect of porosity,relative draft,and relative water depth are discussed; the choice of suitable range of them is described.The relative draft is more effective for shallow water waves.Model shows decrease in relative draft and leads to reduction of relative wave force,overturning moment,and nunup.It is shown that curtainwallpile breakwaters can operate both effectively and efficiently in the range of relative draft between 0.15 and 0.75.The range 0.5 to 0.2 is also recommended for porosity.

  5. Wave Run-Up on Rubble Breakwaters

    DEFF Research Database (Denmark)

    Van de Walle, Bjorn; De Rouck, Julien; Troch, Peter;

    2005-01-01

    vice versa. Differences in wave run-up results between the various data sets could be explained by a difference in spectral width observed within these data sets. A multi-regression formula was fitted to all wave run-up data. The formula is valid for permeable rubble mound breakwaters covered with......Seven sets of data for wave run-up on a rubble mound breakwater were combined and re-analysed, with full-scale, large-scale and small-scale model test results being taken into account. The dimensionless wave run-up value Ru-2%/Hm0 was considered, where R u-2% is the wave run-up height exceeded by 2......% of the wave run-up events and Hm0 is the significant wave height. The wave run-up data sets were compared and a clear influence of the spectral shape, characterised by the spectral width parameter epsilon, on wave run-up was noticed: high values of epsilon correspond to high values of Ru-2%/Hm0 and...

  6. Risk Assessment for Tuzla Naval Base Breakwater

    Institute of Scientific and Technical Information of China (English)

    Can Elmar BALAS

    2003-01-01

    In the applications of reliability-based risk assessment methodology in Turkey, only wave characteristics, tidal range, storm surge, wave set-up, and structural system parameters were included in the past. Tsunami risk was not considered as a major design parameter and thus, was not included in the computation. After a strong earthquake (Mw=7.4) occurred near the town of Golcuk, Izmit Bay, Western Turkey at 00:01 GMT on August 17, 1999, chaotic water movements were observed on the coast of the Marmara Sea. Rubble mound breakwaters demonstrated very little damage, as predicted by the reliability-based risk assessment model developed in this study for the Tuzla Naval Base. For determination of the probability of occurrence under design conditions, which is a function of storm waves, tidal range, storm surge, and tsunami height, the Monte Carlo simulation was interrelated with the βⅡ method. For the Tuzla Naval Base main breakwater, tsunami was not the key design parameter when compared to storm waves, however, in places with great seismic activity, tsunami risk can be significant depending on the probability of occurrence and the magnitude of the tsunami.

  7. Solitary Wave Propagation Influenced by Submerged Breakwater

    Institute of Scientific and Technical Information of China (English)

    王锦; 左其华; 王登婷

    2013-01-01

    The form of Boussinesq equation derived by Nwogu (1993) using velocity at an arbitrary distance and surface elevation as variables is used to simulate wave surface elevation changes. In the numerical experiment, water depth was divided into five layers with six layer interfaces to simulate velocity at each layer interface. Besides, a physical experiment was carried out to validate numerical model and study solitary wave propagation.“Water column collapsing”method (WCCM) was used to generate solitary wave. A series of wave gauges around an impervious breakwater were set-up in the flume to measure the solitary wave shoaling, run-up, and breaking processes. The results show that the measured data and simulated data are in good agreement. Moreover, simulated and measured surface elevations were analyzed by the wavelet transform method. It shows that different wave frequencies stratified in the wavelet amplitude spectrum. Finally, horizontal and vertical velocities of each layer interface were analyzed in the process of solitary wave propagation through submerged breakwater.

  8. Numerical Simulation on Hydraulic Performances of Quarter Circular Breakwater

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Quarter circular breakwater (QCB) is a new-type breakwater developed from semi-circular breakwater (SCB). The superstructure of QCB is composed of a quarter circular front wall, a horizontal base slab and a vertical rear wall. The width of QCB's base slab is about half that of SCB, which makes QCB suitable to be used on relatively firm soil foundation. The numerical wave flume based on the Reynolds averaged Navier-Stokes equations for impressible viscosity fluid is adopted in this paper to simulate the hydraulic performances of QCB. Since the geometry of both breakwaters is similar and SCB has been studied in depth, the hydraulic performances of QCB are given in comparison with those of SCB.

  9. A Probabilistic Method for Motion Analysis of Caisson Breakwaters

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    It is assumed that, during the design period, the waves acting on breakwaters are divided into three types: standing wave, broken wave and breaking wave,and the wave heights fit the Rayleigh distribution while the water depths, wave periods and duration of breaking wave impact force fit normal distribution. Based on the random samples of water depths, wave heights, wave periods and duration of breaking wave impact force, the types of waves acting on breakwaters are distinguished and the time-history model of the wave force is determined. The motions of caisson breakwaters under the wave force are simulated by a dynamic numerical model and the statistic characteristics of the dynamic responses are analyzed with the Monte Carlo method. A probabilistic procedure to analyze the motion of the breakwater is developed therein. The procedure is illustrated by an example.

  10. Wave transmission prediction of multilayer floating breakwater using neural network

    Digital Repository Service at National Institute of Oceanography (India)

    Mandal, S.; Patil, S.G.; Hegde, A.V.

    In the present study, an artificial neural network method has been applied for wave transmission prediction of multilayer floating breakwater. Two neural network models are constructed based on the parameters which influence the wave transmission...

  11. Experimental investigation of rubble mound breakwaters for wave energy conversion

    DEFF Research Database (Denmark)

    Luppa, C.; Contestabile, P.; Cavallaro, L.;

    2015-01-01

    The paper describes recent laboratory investigation on the breakwater integrated device named “OBREC” (Overtopping BReakwater for Energy Conversion). This technology recently appeared on the wave energy converter scene as an executive outcome of improving composite seawalls by including overtopping...... type wave energy converters [1]. Two complementary experimental campaigns were carried out, in 2012 and in 2014. Several geometries and wave conditions were examined. Preliminary comparison of hydraulic behaviour has been summarized, focusing on reflection analysis and overtopping flow rate...

  12. Single-Layer Cubipod Armored Breakwaters in Punta Langosteira (Spain)

    OpenAIRE

    Corredor, Antonio; Santos, Moisés; Peña, Enrique; Maciñeira, Enrique; GÓMEZ MARTÍN, MARÍA ESTHER; Medina, Josep R.

    2014-01-01

    This paper describes the design process, hydraulic stability tests and construction of two single-layer Cubipod armored breakwaters in the Port of Punta Langosteira (A Coruña, Spain), located on the Atlantic coast of Spain, the first single-layer armors of randomly placed massive concrete armor units. The environmental, geotechnical, economic and logistic conditions favored randomly-placed Cubipods in single-layer armoring. 3D hydraulic stability tests of single-layer Cubipod armored breakwat...

  13. Innovative rubble mound breakwaters for overtopping wave energy conversion

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Contestabile, Pasquale; Nørgaard, Jørgen Quvang Harck;

    2014-01-01

    This paper intends contributing to the development of an economically and environmentally sustainable coastal infrastructure, which combines rubble mound breakwaters with Wave Energy Converters (WEC). The energy is produced by collecting wave overtopping in a front reservoir, which is returned...... experiments. The formulae are provided with the aim to be of direct use to engineers in the preliminary design of a first prototype of combined breakwater and wave energy converter....

  14. Partial Safety Factors for Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Burcharth, H. F.; Christiani, E.

    1995-01-01

    On the basis of the failure modes formulated in the various subtasks calibration of partial safety factors are described in this paper. The partial safety factors can be used to design breakwaters under quite different design conditions, namely probabilities of failure from 0.01 to 0.4, design...... lifetimes from 20 to 100 years and different qualities of wave data. A code of practice where safety is taken into account using partial safety factors is called a level I code. The partial safety factors are calibrated using First Order Reliability Methods (FORM, see Madsen et al. [1]) where...... the reliability is measured by reliability indices. For all significant failure modes limit state functions are formulated and uncertain quantities are modelled by stochastic variables. In section 2 the most important failure modes are mentioned and statistical models for the uncertain parameters are described...

  15. Beach morphologies induced by breakwaters with different orientations

    Science.gov (United States)

    Jackson, Nancy L.; Harley, Mitchell D.; Armaroli, Clara; Nordstrom, Karl F.

    2015-06-01

    A desired outcome in the construction of a detached emerged breakwater is the formation of an accretionary salient in its lee to augment the beach, improve beach amenity and provide an additional buffer from storm waves. The extent to which this salient forms and its morphology are strongly controlled by the breakwater geometry with respect to the original shoreline, sediment availability, and local wave climate. The purpose of this paper is to identify how breakwater geometry and orientation of gaps between individual breakwaters alter the direction of waves entering the gaps and change the asymmetry of the salients. Four distinct breakwater sites along the Emilia-Romagna coastline in Northern Italy were chosen for a detailed field and desktop study comprising three-dimensional topographic and bathymetric surveys, sediment sampling, LiDAR flights and historical shoreline mapping. The orientations of the shorelines at these four sites range over 43°, resulting in different exposures to the dominant waves. The oblique orientations of the gaps between individual breakwater segments at three of the four sites effectively create a "gap window" between breakwaters favoring the exposure of short-period waves from the north and diminishing the effect of longer waves from the dominant east. Salients can be symmetrical despite an acute angle of approach of the dominant deep water waves where refraction is enhanced by offshore topography and breakwaters are parallel to the shore. Waves approaching normal to the gap window undergo less diffraction due to their shorter length relative to the gap window width and undergo less attenuation by breaking and bottom friction if they are locally generated and have short periods. Greater breaking-wave energy on the gap-facing slope of the salient can create shoreline and morphological asymmetry. The implication is that breakwater orientations can be designed or altered to selectively dampen or facilitate wave energy to enhance

  16. A Comparison of Homogeneous and Multi-layered Berm Breakwaters with Respect to Overtopping and Stability

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Skals, Kasper; Burcharth, Hans F.

    2008-01-01

    The paper deals with homogeneous and multi-layer berm breakwaters designed to maximize the utilization of the quarry material. Two wide stone classes are typically used for berm breakwaters with a homogeneous berm.......The paper deals with homogeneous and multi-layer berm breakwaters designed to maximize the utilization of the quarry material. Two wide stone classes are typically used for berm breakwaters with a homogeneous berm....

  17. Study of vertical breakwater reliability based on copulas

    Science.gov (United States)

    Dong, Sheng; Li, Jingjing; Li, Xue; Wei, Yong

    2016-04-01

    The reliability of a vertical breakwater is calculated using direct integration methods based on joint density functions. The horizontal and uplifting wave forces on the vertical breakwater can be well fitted by the lognormal and the Gumbel distributions, respectively. The joint distribution of the horizontal and uplifting wave forces is analyzed using different probabilistic distributions, including the bivariate logistic Gumbel distribution, the bivariate lognormal distribution, and three bivariate Archimedean copulas functions constructed with different marginal distributions simultaneously. We use the fully nested copulas to construct multivariate distributions taking into account related variables. Different goodness fitting tests are carried out to determine the best bivariate copula model for wave forces on a vertical breakwater. We show that a bivariate model constructed by Frank copula gives the best reliability analysis, using marginal distributions of Gumbel and lognormal to account for uplifting pressure and horizontal wave force on a vertical breakwater, respectively. The results show that failure probability of the vertical breakwater calculated by multivariate density function is comparable to those by the Joint Committee on Structural Safety methods. As copulas are suitable for constructing a bivariate or multivariate joint distribution, they have great potential in reliability analysis for other coastal structures.

  18. Design formulas of transmission coefficients for permeable breakwaters

    Directory of Open Access Journals (Sweden)

    Su-xiang ZHANG

    2015-10-01

    Full Text Available New empirical formulas of the transmission coefficient for permeable breakwaters were suggested based on available experimental data regarding the low-crest structure (LCS, including the permeable rubble mound breakwater and pile-type breakwater. The rationality of the present formulas was verified by their comparison with existing empirical and analytical formulas. Numerical flume results were obtained by solving the modified Boussinessq-type wave equations (MBEs, and a new expression relating the friction coefficient to the relative submerged depth was also derived. Comparative analysis shows that the results of the present formulas agree with the numerical flume results as well as available experimental data, and the present formulas are superior to the existing empirical and analytical expressions in estimating the transmission coefficient. The present formulas can provide references for estimation of the transmission coefficient in engineering practice.

  19. Design formulas of transmission coefficients for permeable breakwaters

    Institute of Scientific and Technical Information of China (English)

    Su-xiang ZHANG; Xi LI

    2014-01-01

    Newempirical formulas of the transmission coefficient for permeable breakwaters were suggested based on available experimental data regarding the low-crest structure (LCS), including the permeable rubble mound breakwater and pile-type breakwater. The rationality of the present formulas was verified by their comparison with existing empirical and analytical formulas. Numerical flume results were obtained by solving the modified Boussinessq-type wave equations (MBEs), and a new expression relating the friction coefficientαto the relative submerged depth tsRHwas also derived. Comparative analysis shows that the results of the present formulas agree with the numerical flume results as well as available experimental data, and the present formulas are superior to the existing empirical and analytical expressions in estimating the transmission coefficient. The present formulas can provide references for estimation of the transmission coefficient in engineering practice.

  20. Wave loadings acting on Overtopping Breakwater for Energy Conversion

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Nørgaard, Jørgen Harck; Contestabile, Pasquale;

    2013-01-01

    devices. This paper presents results on wave loading acting on an hybrid WEC named Overtopping BReakwater for Energy Conversion (OBREC). The new design is based on the concept of an integration between a traditional rubble mound breakwater and a front reservoir designed to store the wave overtopping from......Any kind of Wave Energy Converter (WEC) requires information on reliability of technology and on time required for the return of the investment (reasonable payback). The structural response is one of the most important parameters to take in to account for a consistent assessment on innovative...... the incoming wave to produce electricity. 2D hydraulic model tests were carried out at the Department of Civil Engineering, Aalborg University (Denmark). The analyses of hydraulic model tests have identified the main shapes assumed by wave surfaces at the breakwater and respective spatial and temporal pressure...

  1. Flow Field Analysis of Submerged Horizontal Plate Type Breakwater

    Institute of Scientific and Technical Information of China (English)

    张志强; 栾茂田; 王科

    2013-01-01

    Submerged horizontal plate can be considered as a new concept breakwater. In order to reveal the wave elimination mechanism of this type breakwater, boundary element method is utilized to investigate the velocity field around plate carefully. The flow field analysis shows that the interaction between incident wave and reverse flow caused by submerged plate will lead to the formation of wave elimination area around both sides of the plate. The velocity magnitude of flow field has been reduced and this is the main reason of wave elimination.

  2. Definition of Geometry for SSG Breakwater at Hanstholm Location

    DEFF Research Database (Denmark)

    Margheritini, Lucia

    study “Definition of Geometry for SSG breakwater at Hanstholm location”, Contract Report no 89. This became necessary as requirement from the turbine people who claimed it was not feasible for a turbine to work to work with less than 1.7 m of head. Despite this had already been proven not to correspond...... to reality in the WaveDragon case, calculations on power production for crest levels higher than 1.5 m have been here compiled. This study develops within the “Feasibility study for integrated wave energy in the new outer breakwater in the port of Hanstholm”; the project has been financed by Innovation...

  3. A New Formula for Front Slope Recession of Berm Breakwaters

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Burcharth, Hans F.

    2010-01-01

    The front slope stability of breakwaters with a homogeneous berm was studied in a large number of two dimensional model tests at Aalborg University, Denmark. The results are presented together with a new formula for prediction of the berm recession which is the most important parameter for descri......The front slope stability of breakwaters with a homogeneous berm was studied in a large number of two dimensional model tests at Aalborg University, Denmark. The results are presented together with a new formula for prediction of the berm recession which is the most important parameter...

  4. 2-D Model Test Study of the Suape Breakwater, Brazil

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Burcharth, Hans F.; Sopavicius, A.;

    This report deals with a two-dimensional model test study of the extension of the breakwater in Suape, Brazil. One cross-section was tested for stability and overtopping in various sea conditions. The length scale used for the model tests was 1:35. Unless otherwise specified all values given...

  5. A database of major breakwaters around the world

    NARCIS (Netherlands)

    Allsop, N.W.H.; Cork, R.S.; Verhagen, H.J.

    2009-01-01

    This paper introduces a co-operative project between HR Wallingford UK (HRW) and Delft University of Technology, Netherlands, (TUD) to develop, populate, and then to apply a database on all major breakwaters around the world. It builds on, and revives, similar initiatives that originate in the late

  6. Design And Construction Of Mounds For Breakwaters And Coastal Protection

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Barends, F.B.J.; Brebner, A.;

    Design and construction of mound breakwaters has during the last 5 to 10 years entered a new era. The major reason for that is the realization of problems encountered as it became necessary to erect port structures on more exposed shores and in deeper waters. As a consequence of that the P.I.A.N....

  7. Design of Vertical Wall Caisson Breakwaters using Partial Safety Factors

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Sørensen, John Dalsgaard

    1999-01-01

    The paper presents a new system for implementation of target reliability in caisson breakwater designs by means of partial safety factors. The development of the system is explained, and tables of partial safety factors are presented for important overall stability failure modes related to caisson...

  8. Comparison construction costs conventional rubblemound breakwaters/bermbreakwater

    NARCIS (Netherlands)

    Hauer, M.; Op den Velde, W.; Vrijling, J.K.; D' Angremond, K.

    1995-01-01

    Given a harbour location and a wave-climate, two different types of rubble-mound breakwaters were designed. Using realistic quarry yield curves and prices for production, transport and constmction, the total costs of the conventional statically stable and dynamically stable bermbreakwater designs we

  9. Overtopping of Rubble Mound Breakwaters with Front Reservoir

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Andersen, Thomas Lykke

    2006-01-01

    The admissible overtopping discharge is a key parameter in fundamental design of breakwaters. Quite often there is a wish to limit the crest level of the structure, mainly for aesthetic reasons as a high structure might block the sea view from restaurants, promenades etc....

  10. Scour at Breakwaters Under Coombined Waves and Current

    DEFF Research Database (Denmark)

    Carstensen, Stefan; Sumer, B. Mutlu

    2015-01-01

    Bed profiles perpendicular to breakwater have been measured for orthogonal combined wave and current scour. The bedprofiles show the distinct features of the wave scour forming due to the presence of recirculating cells, namely deposition/scour at the antinodes/nodes depending on whether the sedi...

  11. Preliminary Results of Breakwater Round-Head Tests

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Liu, Z.

    1995-01-01

    The rational design diagram for Dolos armour should incorporate both the hydraulic stability and the structural integrity. The previous tests performed by Aalborg University (AU) made available such design diagram for the trunk of Dolos breakwater without superstructures (Burcharth et al. 1992...

  12. Wave Impacts on Caisson Breakwaters Situated in Multidirectionally Breaking Seas

    DEFF Research Database (Denmark)

    Grønbech, J.; Burcharth, Hans F.; Frigaard, Peter;

    1999-01-01

    Attention has been addressed to the effects of wave obliquity and multidirectionality on the wave loads on vertical caisson breakwaters situated in non breaking seas. Within the joint European (MAST-LIP-TAW) research project, a 3D model investigation was carried out at Delft Hydraulics to assess...

  13. Wave Impacts on Caisson Breakwaters Situated in Multidirectionally Breaking Seas

    DEFF Research Database (Denmark)

    Grønbech, J.; Burcharth, Hans F.; Frigaard, Peter;

    1998-01-01

    Attention has been addressed to the effects of wave obliquity and multidirectionality on the wave loads on vertical caisson breakwaters situated in non breaking seas. Within the joint European (MAST-LIP-TAW) research project, a 3D model investigation was carried out at Delft Hydraulics to assess...

  14. Numerical evaluation of stability methods for rubble mound breakwater toes

    NARCIS (Netherlands)

    Verpoorten, S.P.K.; Ockeloen, W.J.; Verhagen, H.J.

    2015-01-01

    Since 1977 dedicated studies are made to the stability of rubble mound break-water toes under wave attack. A large number of stability methods is available, but prediction accuracy is low and validity ranges are too small for use in prac-tice. In this research the decoupled model approach is used to

  15. Displacement of Monolithic Rubble-Mound Breakwater Crown-Walls

    DEFF Research Database (Denmark)

    Nørgaard, Jørgen Harck; Andersen, Lars Vabbersgaard; Andersen, Thomas Lykke;

    2012-01-01

    studies on caisson breakwaters, but correction terms are suggested in the present paper to obtain almost equal measured and estimated displacements. This is of great practical importance since many existing rubble-mound crown-walls are subjected to increasing wave loads due to rising sea water level from...

  16. Overtopping And Rear Slope Stabillity Of Reshaping Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans Falk; Lykke Andersen, Thomas

    2003-01-01

    An experimental study of overtopping and rear slope stability of reshaping breakwaters has been carried out. The variation of those two parameters with crest width, crest freeboard and sea state was investigated. The tests showed that the variation in overtopping discharge with crest freeboard...

  17. Modelling of Performance of Caisson Type Breakwaters under Extreme Waves

    Science.gov (United States)

    Güney Doǧan, Gözde; Özyurt Tarakcıoǧlu, Gülizar; Baykal, Cüneyt

    2016-04-01

    Many coastal structures are designed without considering loads of tsunami-like waves or long waves although they are constructed in areas prone to encounter these waves. Performance of caisson type breakwaters under extreme swells is tested in Middle East Technical University (METU) Coastal and Ocean Engineering Laboratory. This paper presents the comparison of pressure measurements taken along the surface of caisson type breakwaters and obtained from numerical modelling of them using IH2VOF as well as damage behavior of the breakwater under the same extreme swells tested in a wave flume at METU. Experiments are conducted in the 1.5 m wide wave flume, which is divided into two parallel sections (0.74 m wide each). A piston type of wave maker is used to generate the long wave conditions located at one end of the wave basin. Water depth is determined as 0.4m and kept constant during the experiments. A caisson type breakwater is constructed to one side of the divided flume. The model scale, based on the Froude similitude law, is chosen as 1:50. 7 different wave conditions are applied in the tests as the wave period ranging from 14.6 s to 34.7 s, wave heights from 3.5 m to 7.5 m and steepness from 0.002 to 0.015 in prototype scale. The design wave parameters for the breakwater were 5m wave height and 9.5s wave period in prototype. To determine the damage of the breakwater which were designed according to this wave but tested under swell waves, video and photo analysis as well as breakwater profile measurements before and after each test are performed. Further investigations are carried out about the acting wave forces on the concrete blocks of the caisson structures via pressure measurements on the surfaces of these structures where the structures are fixed to the channel bottom minimizing. Finally, these pressure measurements will be compared with the results obtained from the numerical study using IH2VOF which is one of the RANS models that can be applied to simulate

  18. Vibrating-Rocking Motion of Caisson Breakwater Under Breaking Wave Impact

    Institute of Scientific and Technical Information of China (English)

    王元战; 郑斌

    2001-01-01

    The possible motions of a caisson breakwater under dynamic load excitation include vibrating, vibrating-sliding andvibrating-rocking motions. The models of vibrating motion and vibrating-sliding motion have been proposed in an earlypaper. In this paper, a model of vibrating-rocking motion of caisson breakwaters under breaking wave impact is presented, which can be used to simulate the histories of vibrating-rocking motion of caisson breakwaters. The effect of rocking motion on the displacement, rotation, sliding force and overturning moment of breakwaters is investigated. In casethe overturning moment exceeds the stability moment ofa caisson, the caisson may only rock. The caisson overturns only in case the rocking angle exceeds the critical angle. It is shown that the sliding force and overturning moment of break-waters can be reduced effectively due to the rocking motion. It is proposed that some rocking motion should be allowedin breakwater design.

  19. Optimum Safety Levels and Design Rules for the Icelandic Type Berm Breakwater

    DEFF Research Database (Denmark)

    Sigurdarson, Sigurdur; van der Meer, Jentsje W.; Burcharth, Hans F.;

    2007-01-01

    Guidance on selection of breakwater types and related design safety levels for breakwaters are almost non-existent, which is the reason that PIANC has initiated working group 47 on this subject. This paper presents ongoing work particulary on the Icelandic type berm breakwater within the PIANC...... working group. It will concentrate on design guidance and on the optimum safety levels for this type of structure....

  20. MODELING THE INTERACTION OF SOLITARY WAVES AND SEMI-CIRCULAR BREAKWATERS BY USING UNSTEADY REYNOLDS EQUATIONS

    Institute of Scientific and Technical Information of China (English)

    刘长根; 陶建华

    2004-01-01

    A vertical 2-D numerical wave model was developed based on unsteady Reynolds equations. In this model, the k-epsilon models were used to close the Reynolds equations, and volume of fluid(VOF) method was used to reconstruct the free surface. The model was verified by experimental data. Then the model was used to simulate solitary wave interaction with submerged, alternative submerged and emerged semi-circular breakwaters. The process of velocity field, pressure field and the wave surface near the breakwaters was obtained. It is found that when the semi-circular breakwater is submerged, a large vortex will be generated at the bottom of the lee side wall of the breakwater; when the still water depth is equal to the radius of the semi-circular breakwater, a pair of large vortices will be generated near the shoreward wall of the semi-circular breakwater due to wave impacting, but the velocity near the bottom of the lee side wall of the breakwater is always relatively small. When the semi-circular breakwater is emerged, and solitary wave cannot overtop it, the solitary wave surface will run up and down secondarily during reflecting from the breakwater. It can be further used to estate the diffusing and transportation of the contamination and transportation of suspended sediment.

  1. Time-domain hydrodynamic analysis of pontoon-plate floating breakwater

    Directory of Open Access Journals (Sweden)

    Zhi-jie CHEN

    2012-09-01

    Full Text Available The hydrodynamic behaviors of a floating breakwater consisting of a rectangular pontoon and horizontal plates are studied theoretically. The fluid motion is idealized as two-dimensional linear potential flow. The motions of the floating breakwater are assumed to be two-dimensional in sway, heave, and roll. The solution to the fluid motion is derived by transforming the governing differential equation into the integral equation on the boundary in time domain with the Green’s function method. The motion equations of the floating breakwater are established and solved with the fourth-order Runge-Kutta method to obtain the displacement and velocity of the breakwater. The mooring forces are computed with the static method. The computational results of the wave transmission coefficient, the motion responses, and the mooring forces of the pontoon-plate floating breakwater are given. It is indicated that the relative width of the pontoon is an important factor influencing the wave transmission coefficient of the floating breakwater. The transmission coefficient decreases obviously as the relative width of the pontoon increases. The horizontal plates help to reduce the wave transmission over the floating breakwater. The motion responses and the mooring forces of the pontoon-plate floating breakwater are less than those of the pontoon floating breakwater. The mooring force at the offshore side is larger than that at the onshore side.

  2. Full Wave Solution for Hydrodynamic Behaviors of Pile Breakwater

    Institute of Scientific and Technical Information of China (English)

    ZHU Da-tong

    2013-01-01

    Rayleigh expansion is used to study the water-wave interaction with a row of pile breakwater in finite water depth.Evanescent waves,the wave energy dissipated on the fluid resistance and the thickness of the breakwater are totally included in the model.The formulae of wave reflection and transmission coefficients are obtained.The accuracy of the present model is verified by a comparison with existing results.It is found that the predicted wave reflection and transmission coefficients for the zero order are all highly consistent with the experimental data (Hagiwara,1984;Isaacson et al.,1998) and plane wave solutions (Zhu,2011).The losses of the wave energy for the fluid passing through slits play an important role,which removes the phenomena of enhanced wave transmission.

  3. An Alternative Stability Equation For Rock Armoured Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Hald, Tue; Burcharth, H. F.

    2000-01-01

    be straight forward to assume, that a relation between the exerted wave loads and the stability of the armour layer would be of major interest, but the normal approach to the problem has simply been to relate easy accessible wave parameters, e.g. wave height and period, directly to the single unit weight......Rubble mound breakwaters are by far the most common type of breakwater, the importance of which is clearly reflected in the vast amount of published research. Especially, the hydraulic stability of the main armour layer has been studied in order to obtain reliable design equations. It should....... Taking a closer look on the stability formulae large differences in the influence of the different parameters are observed although several points of resemblance are observed. Despite the major efforts in obtaining a reliable stability equation a large scatter between damage predicted by the stability...

  4. Wave interaction with a new type perforated breakwater

    Institute of Scientific and Technical Information of China (English)

    Yong Liu; Yucheng Li; Bin Teng

    2007-01-01

    In this study examined is the wave interaction with a new modified perforated breakwater, consisting of a perforated front wall, a solid back wall and a wave absorb-ing chamber between them with a two-layer rock-filled core.The fluid domain is divided into three sub-domains accord-ing to the components of the breakwater. Then by means of the matched eigenfunction expansion method, an analytical solution is obtained to assess the hydrodynamic performance of the new structure. An approach based on a step approach method is introduced Io solve the complex dispersion equa-tions for water wave motions within two-layer porous media.Numerical results of the present model are compared with previous limiting cases. The effects of rock fill on the reflec-tion coefficient and the horizontal wave force are discussed.

  5. Horizontal Coherence of Wave Forces on Vertical Wall Breakwaters

    DEFF Research Database (Denmark)

    Archetti, R.; Frigaard, Peter; Lamberti, A.;

    2001-01-01

    Spatial coherence of wave impact pressures at a vertical breakwater in multidirectional seas is studied as part of an EU project under the LSF‐TMR programme. The lay out and programme of tests are shortly described. A method for the identification of breaking waves is presented. The percentage...... of breaking waves for increasing wave height are estimated and compared with existing empirical formulae. The horizontal dimension of the breaker is investigated using two different methodologies: the first analyses the decreasing of the highest 1/250 force with increasing horizontal dimension of the caisson......, with special attention to the effects of wave spreading, and the second analyses the spatial correlation of impulsive force per unit length along the breakwater....

  6. Risk Assessment of Vertical Breakwaters -- A Case Study in Turkey

    Institute of Scientific and Technical Information of China (English)

    Can Elmar BALAS; Levent KOC

    2002-01-01

    In the reliability-risk assessment, the second order reliability index (βⅡ) method and the Conditional ExpectationMonte Carlo (CEMC) simulation are interrelated as a new Level Ⅲ approach for the analysis of the safety level of theDalaman yacht harbor vertical wall breakwater in Turkey. The missing wave data of the Dalaman measurement station arehindcasted by use of muhi-layer feed-forward neural networks with the steepest descent and conjugate gradient algorithms.The structural failure probabilities of sliding and overturning failure modes are forecasted by approximation of the failure sur-face with a second-degree polynomial of an equal curvature at the design point. In the new approach, for each randomlygenerated load and tide combination, the joint failure probability reflects both the occurrence probability of loading conditionand the structural failure risk at the limit state. The approach can be applied to risk assessment of vertical breakwaters inshort CPU durations of portable computers.

  7. 2-D Physical Modeling to Measure the Effectiveness of Perforated Skirt Breakwater for Short-Period Waves

    OpenAIRE

    Harman Ajiwibowo

    2011-01-01

    The effectiveness of a breakwater can be measured by quantifying the transmission coefficient (KT). The smaller the coefficient, the better the performance of the breakwater. A physical modeling on the proposed breakwater was conducted to identify the coefficient of Perforated Skirt Breakwater (PSB). The PSB model was tested in 2-D wave flume at Ocean Wave Research Laboratory FTSL ITB, to obtain the effectiveness of PSB for short-period waves (prototype periods, Tp= 4 second and smaller). The...

  8. Model Test Study of the Breakwater at the Dubai Port Terminal in Callao, Peru

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Burcharth, Hans F.

    This report deals with a two-dimensional model test study of the new breakwater for the Dubai Port terminal in Callao, Peru. Two cross-sections were tested namely the outer part of the breakwater (Section C) and a cross-section at the container terminal area (Section A). The length scale used...

  9. Experimental Study and Numerical Modeling of Wave Induced Pore Pressure Attenuation Inside a Rubble Mound Breakwater

    DEFF Research Database (Denmark)

    Troch, Peter; Rouck, Julien De; Burcharth, Hans Falk

    2003-01-01

    attenuation is studied using experimental data (in Section 2) and using a numerical wave flume (in Section 3). The experimental study includes the analysis of large scale data from a physical breakwater model and prototype data from the Zeebrugge breakwater. The large scale data are taken from literature...

  10. Optimum Safety Levels and Design Rules for the Icelandic-Type Berm Breakwater

    DEFF Research Database (Denmark)

    Sigurdarson, Sigurdur; van der Meer, Jentsje W.; Burcharth, Hans F.;

    2009-01-01

    This paper gives first an elaboration of berm recession equations for berm breakwaters and then new deterministic design rules for the Icelandic-type berm breakwater. Safety optimization calculations have been performed for a mild depth limited wave climate and for a situation a deep water. Repair...

  11. Experimental study of 2D scour and its protection at a rubble-mound breakwater

    DEFF Research Database (Denmark)

    Sumer, B. Mutlu; Fredsøe, Jørgen

    2000-01-01

    conducted with both regular waves and irregular waves. It was found that the scour/deposition pattern in front of the rubble-mound breakwater emerges in the form of alternating scour and deposition areas lying parallel to the breakwater, similar to the case of the vertical-wall breakwater. The maximum scour......This study deals with the 2D scour at the trunk section of a rubble-mound breakwater. Two breakwater models with slopes of 1:1.2 and 1:1.75 are employed for the experimental study of the scour in a wave flume. 2D scour at a vertical-wall breakwater was also included as a reference case. Tests were...... depth, however, was found to be smaller in the present case than that of the vertical-wall breakwater case. In the case of the irregular waves, the scour depth at the breakwater decreases with respect to that experienced in the case of the regular waves. Countermeasures for toe protection were also...

  12. Flow and Turbulence at Rubble-Mound Breakwater Armor Layers under Solitary Wave

    DEFF Research Database (Denmark)

    Jensen, Bjarne; Christensen, Erik Damgaard; Sumer, B. Mutlu;

    2015-01-01

    to the breakwater, and (3) a porous breakwater where the porous core was added below the breakwater front. One breakwater slope of 1:1.5 was applied. In this paper the focus is on the details of a single sequence of wave approach, run-up, and rundown. To isolate this sequence the experiments were performed applying......This paper presents the results of an experimental investigation of the flow and turbulence at the armor layer of rubble-mound breakwaters during wave action. The study focused on the details of the flow and turbulence in the armor layer and on the effect of the porous core on flow and stability...... a solitary wave. The individual sources of turbulence generation were distinguished using Laser Doppler anemometry measurements, and the effect of the armor layer and porous core was described in terms of a reduced impact of the rundown process, production of lee wake turbulence, and less transport...

  13. Scaled Boundary Finite Element Analysis of Wave Passing A Submerged Breakwater

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The scaled boundary finite element method (SBFEM) is a novel semi-analytical technique combining the advantage of the finite element method (FEM) and the boundary element method (BEM) with its unique properties. In this paper, the SBFEM is used for computing wave passing submerged breakwaters, and the reflection coefficient and transmission coefficient are given for the case of wave passing by a rectangular submerged breakwater, a rigid submerged barrier breakwater and a trapezium submerged breakwater in a constant water depth. The results are compared with the analytical solution and experimental results. Good agreement is obtained. Through comparison with the results using the dual boundary element method (DBEM), it is found that the SBFEM can obtain higher accuracy with fewer elements. Many submerged breakwaters with different dimensions are computed by the SBFEM, and the changing character of the reflection coefficient and the transmission coefficient are given in the current study.

  14. Investigation of Hydrodynamic Parameters and the Effects of Breakwaters During the 2011 Great East Japan Tsunami in Kamaishi Bay

    Science.gov (United States)

    Ozer Sozdinler, Ceren; Yalciner, Ahmet Cevdet; Zaytsev, Andrey; Suppasri, Anawat; Imamura, Fumihiko

    2015-12-01

    The March 2011 Great East Japan Tsunami was one of the most disastrous tsunami events on record, affecting the east coast of Japan to an extreme degree. Extensive currents combined with flow depths in inundation zones account for this devastating impact. Video footage taken by the eyewitnesses reveals the destructive effect and dragging capability of strong tsunami currents along the coast. This study provides a numerical modeling study in Kamaishi Bay, calculating the damage inflicted by tsunami waves on structures and coastlines in terms of the square of the Froude number Fr 2 ; and also other calculated hydrodynamic parameters, such as the distribution of instantaneous flow depths, maximum currents and water surface elevations that occurred during this catastrophic tsunami. Analyses were performed by using the tsunami numerical modeling code NAMI DANCE with nested domains at a higher resolution. The effect of the Kamaishi breakwater on the tsunami inundation distance and coastal damage was tested by using the conditions of "with breakwater," "without breakwater," and "damaged breakwater." Results show that the difference between the hydrostatic pressure on the seaward side of the breakwater and the leeward side of the breakwater is quite high, clarifying conditions contributing to failure of the breakwater. Lower water surface elevations were calculated in the case of a breakwater existing at the entrance, a partly valid condition for the damaged breakwater case. The results are different for current velocities and Fr_{max}2 in the "with breakwater" condition due to the concentration of energy through the breakwater gaps.

  15. Numerical Simulation of Wave Interaction with Perforated Caisson Breakwaters

    Institute of Scientific and Technical Information of China (English)

    陈雪峰; 李玉成; 王永学; 董国海; 白雪

    2003-01-01

    The volume of fluid (VOF) method is presented to determine the reflection coefficient of and the total horizontal wave force on perforated caisson breakwaters. The present numerical model is compared with a linear analytic solution obtained by Sahoo et al. (2000). Also this model is verified with the authors′ laboratory data. It is found that the numerical model is in good agreement with the regression equations obtained from the experimental data. The present numerical method is further discussed to relate porosity, the relative wave absorbing chamber depth, the reflection coefficient of perforated caissons and the total horizontal force on them.

  16. Overtopping of Rubble Mound Breakwaters with Front Reservoir

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Andersen, Thomas Lykke

    2007-01-01

    The design and performance of breakwaters with front reservoir are discussed on the basis of physical 2-D model tests with a number of cross sections, in which vertopping discharge and spatial distribution, wave forces on inner parapet walls, and stability of reservoir armour were studied....... The sensitivity of these quantities to the width of the reservoir is discussed. It is demonstrated that front reservoir solutions are more economical than conventional cross section solutions, such as bermed structures and mild slope structures, in cases where low crests and small overtopping discharges...

  17. Wave Loadings Acting on an Innovative Breakwater for Energy Production

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Ciardulli, F.; Buccino, M.;

    2011-01-01

    The paper reports on 2D small scale experiments conducted to investigate wave loadings acting on a pilot project of device for the conversion of wave energy into electricity. The conversion concept is based on the overtopping principle and the structure is worldwide known with the acronym SSG...... interval. It is also shown that two calculation methods widely employed in the Japanese design practice of vertical face breakwaters, namely Goda (1975) and Hiroi (1919), could be used to achieve safe estimates of the hydrodynamic loadings....

  18. Wave Run-Up on a Rubble Mound Breakwater

    DEFF Research Database (Denmark)

    Rouck, J. De; Troch, P.; Walle, B. Van de;

    2001-01-01

    found by laboratory testing and reported in literature. The design of the crest height of a breakwater is mainly based on wave run-up values obtained by small scale model tests. Prototype measurements are seen as the big challenge to be addressed to verify small scale model test results. Therefore......-o dimensional models (1:30) and on one thr-e dimensional scale model (1:40). For a better determination of wave run-up on the scale models, a novel step gauge is developed. Still, differences between results of prototype measurement and small scale model test results and between the various laboratory results...

  19. Dynamic Stability Analysis of Caisson Breakwater in Lifetime Considering the Annual Frequency of Severe Storm

    Institute of Scientific and Technical Information of China (English)

    王禹迟; 王元战; 洪宁宁

    2015-01-01

    In the dynamic stability analysis of a caisson breakwater, most of current studies pay attention to the motion characteristics of caisson breakwaters under a single periodical breaking wave excitation. And in the lifetime stability analysis of caisson breakwater, it is assumed that the caisson breakwater suffers storm wave excitation once annually in the design lifetime. However, the number of annual severe storm occurrence is a random variable. In this paper, a series of random waves are generated by the Wen Sheng-chang wave spectrum, and the histories of successive and long-term random wave forces are built up by using the improved Goda wave force model. It is assumed that the number of annual severe storm occurrence is in the Poisson distribution over the 50-year design lifetime, and the history of random wave excitation is generated for each storm by the wave spectrum. The response histories of the caisson breakwater to the random waves over 50-year design lifetime are calculated and taken as a set of samples. On the basis of the Monte Carlo simulation technique, a large number of samples can be obtained, and the probability assessment of the safety of the breakwater during the complete design lifetime is obtained by statistical analysis of a large number of samples. Finally, the procedure of probability assessment of the breakwater safety is illustrated by an example.

  20. Ecological Value of Submerged Breakwaters for Habitat Enhancement on a Residential Scale

    Science.gov (United States)

    Scyphers, Steven B.; Powers, Sean P.; Heck, Kenneth L.

    2015-02-01

    Estuarine shorelines have been degraded since humans arrived in the coastal zone. In recent history, a major cause of habitat degradation has been the armoring of shorelines with vertical walls to protect property from erosive wave energy; however, a lack of practical alternatives that maintain or enhance ecological function has limited the options of waterfront residents and coastal zone managers. We experimentally investigated the habitat value of two configurations of submerged breakwaters constructed along an eroding shoreline in northwest Mobile Bay, AL (USA). Breakwaters comprised of bagged oyster shell or Reef Ball™ concrete domes were built by a community-based restoration effort. Post-deployment monitoring found that: bagged oyster breakwaters supported much higher densities of live ribbed mussels than Reef Ball breakwaters; both breakwater configurations supported increased species richness of juvenile and smaller fishes compared to controls; and that larger fishes did not appear to be affected by breakwater presence. Our study demonstrates that ecologically degraded shorelines can be augmented with small-scale breakwaters at reasonable cost and that these complex structures can serve as habitat for filter-feeding bivalves, mobile invertebrates, and young fishes. Understanding the degree to which these structures mitigate erosive wave energy and protect uplands will require a longer time frame than our 2-year-long study.

  1. Analysis Model of Dynamic Response on the Circular Caisson Breakwater Under Random Wave

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The random wave load is applied to dynamic response analysis of circular caisson breakwater. The motion process of circular caisson breakwater is classified as rotation motion mode and rotation-and-sliding motion mode. The dynamic model system composed of damper-antislider to control the lateral sliding is introduced, and corresponding dynamic equations of two motion modes are established. The formulas to calculate added mass and new conversion relation of the unit rotational stiffness coefficient are put forward according to the characteristic of the circular caisson breakwater. An engineering case is calculated by a program compiled in Fortran language using proposed dynamic model and method. The validity of the model is calibrated.

  2. Overtopping on Rubble Mound Breakwaters for Low Steepness Waves in Deep and Depth Limited Conditions

    DEFF Research Database (Denmark)

    Færch Christensen, Nicole; Røge, Mads Sønderstrup; Thomsen, Jonas Bjerg;

    2014-01-01

    In this paper, the investigation of overtopping on rubble mound breakwaters for low steepness waves in both deep and shallow-water conditions are presented. The existing formulae provide quite different results for long waves for both conventional and berm breakwaters. Therefore, new model tests...... with focus on long waves have been performed for both types of breakwaters. The new model tests showed some deviation from the formulae. Therefore, limitations in the use of the present methods and an update for one of the methods are presented....

  3. Wave Run-up on the Zeebrugge Rubble Mound Breakwater

    DEFF Research Database (Denmark)

    De Rouck, Julien; de Walle, Bjorn Van; Troch, Peter;

    2007-01-01

    Full-scale wave run-up measurements have been carried out on the Zeebrugge rubble mound breakwater in the frame of the EU-funded OPTICREST project. Wave run-up has been measured by a run-up gauge and by a so-called spiderweb system. The dimensionless wave run-up value Ru2%Hm0 measured in Zeebrugge...... equals 1.77 for Iribarren number xi(om) = 3.63. An (apparent) influence of the water level on wave run-up has been observed. The porosity of the armor layer has a significant influence on wave run-up and may explain the dependency of wave run-up on the water level observed in Zeebrugge. Full-scale...... measurement results have been compared to literature data. The full-scale wave run-up data are in good agreement with the existing results of wave run-up tests with rip-rap slopes but are clearly higher than other wave run-up data resulting from tests with rubble mound breakwaters....

  4. Estimating transmitted waves of floating breakwater using support vector regression model

    Digital Repository Service at National Institute of Oceanography (India)

    Mandal, S.; Hegde, A.V.; Kumar, V.; Patil, S.G.

    Planning and design of coastal protection works like floating breakwaters requires information about the performance characteristics of the structure in reducing the wave energy. They can be used as a temporary protection for offshore activities...

  5. Innovative Design for Sea Dikes and Breakwaters for Wave Energy Conversion

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Stagonas, Dimitris; Müller, Gerald;

    2012-01-01

    This paper intends contributing to an economically and environmentally sustainable development of coastal infrastructures by investigating the possibility of combining together breakwaters and Wave Energy Converters (WEC). The latter change the wave energy to electricity, which may serve both the...

  6. Final Report for Full-Scale Load Monitoring of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Frigaard, Peter; Helm-Petersen, Jacob;

    As associated partner, Aalborg University (AU) has participated in different aspects of "the Zeebrugge project" . At an early stage AU has developed and tested an algorithm aiming at deducing incident waves at the prototype breakwater by reflection analysis. Secondly AU, has been engaged with the......As associated partner, Aalborg University (AU) has participated in different aspects of "the Zeebrugge project" . At an early stage AU has developed and tested an algorithm aiming at deducing incident waves at the prototype breakwater by reflection analysis. Secondly AU, has been engaged...... with the development of a numerical model able to predict the hydraulic response of the Zeebrugge breakwater. Finally, AU has carried out an extensive number of small-scale model tests (1:65) with the Zeebrugge breakwater with the aim of investigating scale-effects....

  7. Risk Analysis of Breakwater Caisson Under Wave Attack Using Load Surface Approximation

    Institute of Scientific and Technical Information of China (English)

    Dong Hyawn KIM

    2014-01-01

    A new load surface based approach to the reliability analysis of caisson-type breakwater is proposed. Uncertainties of the horizontal and vertical wave loads acting on breakwater are considered by using the so-called load surfaces, which can be estimated as functions of wave height, water level, and so on. Then, the first-order reliability method (FORM) can be applied to determine the probability of failure under the wave action. In this way, the reliability analysis of breakwaters with uncertainties both in wave height and in water level is possible. Moreover, the uncertainty in wave breaking can be taken into account by considering a random variable for wave height ratio which relates the significant wave height to the maximum wave height. The proposed approach is applied numerically to the reliability analysis of caisson breakwater under wave attack that may undergo partial or full wave breaking.

  8. Oblique and Multi-Directional Random Wave Loads on Vertical Breakwaters

    Institute of Scientific and Technical Information of China (English)

    俞聿修; 李本霞; 张宁川

    2003-01-01

    Extensive 3-D model tests have been performed to study the effects of wave obliquity and multi-directionality on the wave loads acting on vertical breakwaters. The variation of horizontal and uplift forces acting on an unit length of a breakwater with wave direction, the longitudinal distribution of wave forces, as well as the longitudinal load reduction are analyzed. Some empirical formulae of the longitudinal distribution coefficient and the longitudinal load reduction factor are presented for practical use.

  9. Wave Defending Effects of V-Type Bottom-Mounted Breakwaters

    Institute of Scientific and Technical Information of China (English)

    MIAO Guo-ping; CHENG Jian-sheng; YOU Yun-xiang; WANG Jing-quan

    2005-01-01

    An analytical method is developed for the study of the wave defending effects of the V-type bottom-mounted breakwater. The breakwater is assumed to be rigid, thin, impermeable and vertically located in water of constant depth. The fluid domain is divided into three sub-regions by an imaginary interface. The velocity potential in each region is expanded by eigenfunctions. By satisfying the corresponding boundary conditions and natching conditions in and between sub-regions, a set of linear algebraic equations can be obtained to determine the unknown coefficients for the eigenfunction ex pansions for each sub-region. The accuracy of the present model is verified by a comparison with existing results for the case of an isolated breakwater. Numerical results, in the form of contour maps of the relative wave amplitude around the breakwater, are presented for a range of wave and breakwater parameters. The results show that the V-type bottommounted breakwater is generally effective in defending against waves. In general, the wave height in the protected area is about 20 ~ 50 percent of the incident wave height.

  10. Wave Height Transformation and Set-up Between A Submerged Permeable Breakwater and A Seawall

    Institute of Scientific and Technical Information of China (English)

    TSAI Ching-piao; YU Chien-hung; CHEN Hong-bin; CHEN Hsin-yu

    2012-01-01

    In this study,we investigated wave transformation and wave set-up between a submerged permeable breakwater and a seawall.Modified time-dependent mild-slope equations,which involve parameters of the porous medium,were used to calculate the wave height transformation and the mean water level change around a submerged breakwater.The numerical solution is verified with experimental data.The simulated results show that modulations of the wave profile and wave set-up are clearly observed between the submerged breakwater and the seawall.In contrast to cases without a seawall,the node or pseudo-node of wave height evolution can be found between the submerged breakwater and the seawall.Higher wave set-up occurs if the nodal or pseudo-nodal point appears near the submerged breakwater.We also examined the influence of the porosity and friction factor of the submerged permeable breakwater on wave transformation and set-up.

  11. Overtopping of Berm Breakwaters Extension of Overtopping Formula

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Burcharth, H. F.

    2005-01-01

    ) formula and the present improved formula. However, for a more stable structure and low wave steepness the improved formula performs better. Six different data sets are used to study the validity of the Lykke Andersen & Burcharth (2004) formula, the present improved formula and the CLASH neural network...... model. The present improved formula seems to be the best choice. The CLASH NN-Model performs very well for berm breakwater data sets included in the fitting of the NN-Model, but much worse for those not included. This demonstrates some degree of overlearning of the neural network due to limited data...... the formula is improved so it gives reliable estimates also for more stable structures. The extension of the overtopping formula is based on analysis of front slope stability data from many different data sets. In most cases there is only a small difference between the Lykke Andersen & Burcharth (2004...

  12. Wave Induced Loading and Stability of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Hald, Tue

    conducting model tests very large variability in e.g. the degree of stability is observed. This background motivated the investigations conducted in the present study. The objective was to investigate and clarify which wave parameters are important for the hydraulic stability of the armour layer on typical...... related to the hydraulic stability was discussed. Further, governing parameters influencing the stability were identified and their influence quantified to retrieve the state- of-the-art. Model tests were conducted at SINTEF with scale models of prototype breakwaters and both the wave induced loading......The present state of knowledge when designing coastal structures has improved in the recent years. However the available design methods concerning especially rubble mound structures are characterized by a number of empirical and semi-empirical formulae making model tests inevitable and even when...

  13. Armor stability of hardly (or partly) reshaping berm breakwaters

    DEFF Research Database (Denmark)

    Moghim, M. N.; Andersen, Thomas Lykke

    2015-01-01

    the structure toe. The main goal of the present paper is to provide an estimation technique based on this physical principle to predict the deformation of the front slope in terms of the eroded area. The proposed method is verified by comparison with model test data. It is found that by using the maximum wave......This paper deals with stability of hardly (or partly) reshaping berm breakwaters. A simple physical argument is used to derive a new stability formula based on the assumption that the maximum wave force causing damage of armor layer is proportional to the maximum wave momentum flux near...... momentum flux approach the damage to the front slope (eroded area) can be very well predicted. Moreover, a simple method to estimate the eroded area based on measured or calculated berm recession (Rec) and depth of intersection of reshaped and initial profile (hf) is presented. The performance...

  14. Hydrodynamic performance of multiple-row slotted breakwaters

    Science.gov (United States)

    Elbisy, Moussa S.; Mlybari, Ehab M.; Helal, Medhat M.

    2016-06-01

    This study examines the hydrodynamic performance of multiple-row vertical slotted breakwaters. We developed a mathematical model based on an eigenfunction expansion method and a least squares technique for Stokes second-order waves. The numerical results obtained for limiting cases of double-row and triple-row walls are in good agreement with results of previous studies and experimental results. Comparisons with experimental measurements of the reflection, transmission, and dissipation coefficients ( C R , C T , and C E ) for double-row walls show that the proposed mathematical model adequately reproduces most of the important features. We found that for double-row walls, the C R increases with increasing wave number, kd, and with a decreasing permeable wall part, dm. The C T follows the opposite trend. The C E slowly increases with an increasing kd for lower kd values, reaches a maximum, and then decreases again. In addition, an increasing porosity of dm would significantly decrease the C R , while increasing the C T . At lower values of kd, a decreasing porosity increases the C E , but for high values of kd, a decreasing porosity reduces the C E . The numerical results indicate that, for triple-row walls, the effect of the arrangement of the chamber widths on hydrodynamic characteristics is not significant, except when kd0.5, where by the horizontal wave force may be smaller than that of a single wall. On the other hand, the difference between double-row and triple-row vertical slotted breakwaters is marginal.

  15. Oyster reefs as natural breakwaters mitigate shoreline loss and facilitate fisheries.

    Directory of Open Access Journals (Sweden)

    Steven B Scyphers

    Full Text Available Shorelines at the interface of marine, estuarine and terrestrial biomes are among the most degraded and threatened habitats in the coastal zone because of their sensitivity to sea level rise, storms and increased human utilization. Previous efforts to protect shorelines have largely involved constructing bulkheads and seawalls which can detrimentally affect nearshore habitats. Recently, efforts have shifted towards "living shoreline" approaches that include biogenic breakwater reefs. Our study experimentally tested the efficacy of breakwater reefs constructed of oyster shell for protecting eroding coastal shorelines and their effect on nearshore fish and shellfish communities. Along two different stretches of eroding shoreline, we created replicated pairs of subtidal breakwater reefs and established unaltered reference areas as controls. At both sites we measured shoreline and bathymetric change and quantified oyster recruitment, fish and mobile macro-invertebrate abundances. Breakwater reef treatments mitigated shoreline retreat by more than 40% at one site, but overall vegetation retreat and erosion rates were high across all treatments and at both sites. Oyster settlement and subsequent survival were observed at both sites, with mean adult densities reaching more than eighty oysters m(-2 at one site. We found the corridor between intertidal marsh and oyster reef breakwaters supported higher abundances and different communities of fishes than control plots without oyster reef habitat. Among the fishes and mobile invertebrates that appeared to be strongly enhanced were several economically-important species. Blue crabs (Callinectes sapidus were the most clearly enhanced (+297% by the presence of breakwater reefs, while red drum (Sciaenops ocellatus (+108%, spotted seatrout (Cynoscion nebulosus (+88% and flounder (Paralichthys sp. (+79% also benefited. Although the vertical relief of the breakwater reefs was reduced over the course of our study

  16. Report on 3D-model Testing of the Breakwater for a new Port at Puerto de la Cruz, Tenerife

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Meinert, Palle; Andersen, Thomas Lykke;

    The report contains a 3-dimensional model test study of the round head and outer part of the breakwater for the new port at Puerto de la Cruz, Tenerife.......The report contains a 3-dimensional model test study of the round head and outer part of the breakwater for the new port at Puerto de la Cruz, Tenerife....

  17. Comparison of Homogenous and Multi-layered Berm Breakwaters with Respect to Overtopping and Front Slope Stability

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Skals, K. T.; Burcharth, Hans F.

    2009-01-01

    A model test study was conducted to study overtopping and front slope stability of homogenous and multi-layered berm breakwaters. The two breakwater types are compared and cons and pros are listed. The study shows that the optimum number of stone classes might be significantly lower than what has...

  18. Dynamic model of vibrating-sliding-uplift rocking coupled motion and dynamic design method of caisson breakwaters

    Institute of Scientific and Technical Information of China (English)

    WANG; Yuanzhan; HUA; Leina; DONG; Shaowei

    2004-01-01

    Vibrating, sliding and uplift rocking are three elementary motion types of caisson breakwaters. The dynamic model and the numerical simulation method of vibrating-sliding-uplift rocking coupled motion of caisson breakwaters are developed. The histories of displacement, rotation, sliding force and overturning moment of a caisson breakwater under the excitation of breaking wave impact are calculated for the motion models of vibrating, vibrating-sliding, vibrating-uplift rocking and vibrating-sliding-uplift rocking. The effects of various motion models on the stability of caisson breakwaters are investigated. The feasibility of the dynamic design idea that the sliding motion and the uplift rocking motion of caisson breakwaters are allowed under the excitation of breaking wave impact is discussed.

  19. Bble Size Distribution for Waves Propagating over A Submerged Breakwater

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Experiments are carried out to study the characteristics of active bubbles entrained by breaking waves as these propagate over an abruptly topographical change or a submerged breakwater. Underwater sounds generated by the entrained air bubbles are detected by a hydrophone connected to a charge amplifier and a data acquisition system. The size distribution of the bubbles is then determined inversely from the received sound frequencies. The sound signals are converted from time domain to time-frequency domain by applying Gabor transform. The number of bubbles with different sizes are counted from the signal peaks in the time-frequency domain. The characteristics of the bubbles are in terms of bubble size spectra, which account for the variation in bubble probability density related to the bubble radius r. The experimental data demonstrate that the bubble probability density function shows a-2.39 power-law scaling with radius for r>0.8 mm, and a-1.11 power law for r<0.8 mm.

  20. Photogrammetric analysis of rubble mound breakwaters scale model tests

    Directory of Open Access Journals (Sweden)

    João Rodrigues

    2016-09-01

    Full Text Available The main goal of this paper is to develop a photogrammetric method in order to obtain arobust tool for damage assessment and quantification of rubble-mound armour layers during physicalscale model tests. With the present work, an innovative approach based on a reduced number ofdigital photos is proposed to support the identification of affected areas. This work considers twosimple digital photographs recording the instants before and after the completion of the physicaltest. Mathematical techniques were considered in the development of the procedures, enabling thetracking of image differences between photos. The procedures were developed using an open-sourceapplication, Scilab, nevertheless they are not platform dependent. The procedures developed enablethe location and identity of eroded areas in the breakwater armour layer, as well as the possibilityof quantifying them. This ability is confirmed through the calculation of correlation coefficients ineach step of the search for the more damaged area. It is also possible to make an assessment of themovement of armour layer units.

  1. Experimental Study on Stability of Breakwaters with Penetrating Box Foundations

    Institute of Scientific and Technical Information of China (English)

    别社安; 李伟; 李增志; 任增金; 及春宁

    2003-01-01

    The breakwater with top-sealed, shallow and wide penetrating box foundations is a new type of structure, applicable to deep water and soft seabed. The relations of horizontal and vertical bearing capacities of the box foundation structure as well as the instability-induced failure modes to its dimensions and external loads are discussed through static model tests and wave tests. The mechanical properties of the stability of the box foundation are similar to those of embedded rigid foundations, i.e. the vertical stresses at the bottom of the box are distributed in a linear pattern under the action of vertical loads, and passive and active soil pressures are developed at the front and back sides of the box under the action of horizontal loads; there are two instability-induced failure modes of the foundation structure-horizontal slide along the box base and tilting due to insufficient local vertical bearing capacity of the soil beneath the box base. The stability of box foundations can be analyzed by use of the methods applied to analysis of the embedded rigid foundations. To increase the width of the box is the most effective way to improve the stability of box foundations.

  2. Prickly business: abundance of sea urchins on breakwaters and coral reefs in Dubai.

    Science.gov (United States)

    Bauman, Andrew G; Dunshea, Glenn; Feary, David A; Hoey, Andrew S

    2016-04-30

    Echinometra mathaei is a common echinoid on tropical reefs and where abundant plays an important role in the control of algal communities. Despite high prevalence of E. mathaei on southern Persian/Arabian Gulf reefs, their abundance and distribution is poorly known. Spatial and temporal patterns in population abundance were examined at 12 sites between breakwater and natural reef habitats in Dubai (UAE) every 3 months from 2008 to 2010. Within the breakwater habitat, densities were greatest at shallow wave-exposed sites, and reduced with both decreasing wave-exposure and increasing depth. Interestingly, E. mathaei were significantly more abundant on exposed breakwaters than natural reef sites, presumably due to differences in habitat structure and benthic cover. Population abundances differed seasonally, with peak abundances during summer (July-September) and lower abundances in winter (December-February). Seasonal fluctuations are likely the result of peak annual recruitment pulses coupled with increased fish predation from summer to winter. PMID:26563547

  3. Experimental Researches on Reflective and Transmitting Performances of Quarter Circular Breakwater Under Regular and Irregular Waves

    Institute of Scientific and Technical Information of China (English)

    SHI Yan-jiao; WU Mi-ling; JIANG Xue-lian; LI Yan-bao

    2011-01-01

    A series of regular and irregular wave experiments are conducted to study the reflective and transmitting performances of quarter circular breakwater (QCB) in comparison with those of semi-circular breakwater (SCB).Based on regular wave tests,the reflection and transmission characteristics of QCB are analyzed and a few influencing factors are investigated.Then,the wave energy dissipation as wave passing over the breakwater is discussed based on the hydraulic coefficients of QCB and SCB.In irregular wave experiments,the reflection coefficients of QCB and their spectrums are studied.Finally,the comparisons between the experimental results and numerical simulations for QCB under regular and irregular wave conditions are presented.

  4. Dynamic Response Analysis for Embedded Large-Cylinder Breakwaters Under Wave Excitation

    Institute of Scientific and Technical Information of China (English)

    王元战; 祝振宇; 周枝荣

    2004-01-01

    A numerical model is developed for dynamic analysis of large-cylinder breakwaters embedded in soft soil. In the model, the large cylinder is taken as a rigid body divided into elements and the soft soil is replaced by discrete 3D nonlinear spring-dashpot systems. The numerical model is used to simulate the dynamic response of a large-cylinder breakwater to breaking wave excitation. The effects of the dynamic stress-strain relationship models of the soil, the radius and embedded depth of the cylinder, the nonlinear behaviors of the soil, and the limit strength condition of the soil on the dynamic responses of the large-cylinder structure are investigated with an example given. It is indicated that the above-mentioned factors have significant effects on the dynamic responses of an embedded large cylinder breakwater under breaking wave excitation.

  5. Prickly business: abundance of sea urchins on breakwaters and coral reefs in Dubai.

    Science.gov (United States)

    Bauman, Andrew G; Dunshea, Glenn; Feary, David A; Hoey, Andrew S

    2016-04-30

    Echinometra mathaei is a common echinoid on tropical reefs and where abundant plays an important role in the control of algal communities. Despite high prevalence of E. mathaei on southern Persian/Arabian Gulf reefs, their abundance and distribution is poorly known. Spatial and temporal patterns in population abundance were examined at 12 sites between breakwater and natural reef habitats in Dubai (UAE) every 3 months from 2008 to 2010. Within the breakwater habitat, densities were greatest at shallow wave-exposed sites, and reduced with both decreasing wave-exposure and increasing depth. Interestingly, E. mathaei were significantly more abundant on exposed breakwaters than natural reef sites, presumably due to differences in habitat structure and benthic cover. Population abundances differed seasonally, with peak abundances during summer (July-September) and lower abundances in winter (December-February). Seasonal fluctuations are likely the result of peak annual recruitment pulses coupled with increased fish predation from summer to winter.

  6. Scour at the round head of a rubble-mound breakwater

    DEFF Research Database (Denmark)

    Fredsøe, Jørgen; Sumer, B. Mutlu

    1997-01-01

    -side of the breakwater. The Keulegan-Carpenter number based on the base diameter of the breakwater head appears to be the main governing parameter regarding the streaming-induced scour, while a parameter, namely T-p root gH(s)/h, involving the peak wave period, T-p, the significant wave height, H-s, the water depth, h......, and the acceleration due to gravity, g, appears to be the main governing parameter regarding the breaker-induced scour. The scour depth increases with increasing values of these parameters. The conventional stone protection is investigated in the study. An empirical formula is developed for the extent...

  7. Flow under standing waves Part 2. Scour and deposition in front of breakwaters

    DEFF Research Database (Denmark)

    Gislason, Kjartan; Fredsøe, Jørgen; Sumer, B. Mutlu

    2009-01-01

    A 3-D general purpose Navier-Stokes solver was used to calculate the 2-D flow in front of the breakwater. The k-omega, SST (shear-stress transport) model was selected as the turbulence model. The morphologic model of the present code couples the flow solution with a sediment transport description...... and routines for, updating the computational mesh based on the mass balance of sediment. Laboratory experiments of scour also were conducted in a wave flume to obtain data for model verification. Both in the numerical simulations and in the laboratory experiment, two kinds of breakwaters were used: A vertical...

  8. Parameters Influencing Wave Run-Up on a Rubble Mound Breakwater

    DEFF Research Database (Denmark)

    Walle, Björn Van de; Rouck, Julien De; Damme, Luc Van;

    2002-01-01

    Full scale wave run-up measurements have been performed on the Zebrugge rubble mound breakwater. Wave run-up also has been investigated on various small scale models of the Zeebrugge breakwater. A significant difference between the results has been noticed. Additional small scale model testing has...... been carried out on a slightly modified scale model: a regular armour unit pattern has been applied in stead of an irregular pattern as in full scale. The aim of the additional laboratory tests was to investigate the influence of the spectral width parameter and the influence of the position of the...

  9. Stability of Low-Crested Breakwaters in Shallow Water Short Crested Waves

    DEFF Research Database (Denmark)

    Kramer, Morten Mejlhede; Burcharth, Hans Falk

    2003-01-01

    The paper presents results of 3D laboratory experiments on low-crested breakwaters. Two typical structural layouts were tested at model scale in a wave basin at Aalborg University, Denmark, to identify and quantify the influence of various hydrodynamic conditions (obliquity of short crested waves......, wave hight and wave steepness) and structural geometries (crest width and freeboard) on the stability of low-crested breakwaters. Results are given in terms of recommendations for design guidelines for structure stability. Damage parameters for the trunk and the roundhead are proposed based on analysis...

  10. 3D laboratory experiments on a system of low-crested breakwaters under oblique wave attack

    Science.gov (United States)

    Papacharalampous, Georgia; Karantinos, Michalis; Giantsi, Theodora; Moutzouris, Constantinos

    2016-04-01

    Low-crested breakwaters are being increasingly used for shore protection. Hydrodynamics around coastal structures are complicated and have not been fully understood. A series of large scale (1:40) 3D laboratory experiments were carried out in the Laboratory of Harbour Works, National Technical University of Athens to investigate the wave disturbance around a system of two non-parallel to the shoreline breakwaters. The structures were of the type of low-crested, permeable and attacked by obliquely incident waves. Three different water depths were tested in the basin with a range of various different spectra. The transmission and reflection coefficients were measured in the middle of each breakwater. For this purpose, 1 gauge and 4 gauges (in line) were placed on the landward and seaward side of each breakwater respectively. The effect of diffraction is incorporate at the measured wave heights. The measured coefficients are being compared to their corresponding estimated using existing empirical formulas. Most of those formulas neglect wave obliquity.

  11. Riprap stability on the inner slopes of medium-height breakwaters

    NARCIS (Netherlands)

    Verhagen, H.J.; Van Dijk, B.; Nederpel, A.

    2003-01-01

    Medium height breakwaters are subjected to a considerable amount of overtopping. This implies the armour on the inner slope has to stable against overtopping waves. Existing equations do lack some basic understanding of the process of starting up movement of rock on the inner slopes. In case one re

  12. Riprap stability on the inner slopes of medium-height breakwaters

    NARCIS (Netherlands)

    Verhagen, H.J.; Van Dijk, B.; Nederpel, A.

    2003-01-01

    Medium height breakwaters are subjected to a considerable amount of overtopping. This implies the armour on the inner slope has to stable against overtopping waves. Existing equations do lack some basic understanding of the process of starting up movement of rock on the inner slopes. In order to get

  13. Validity of simplified Analysis of Stability of Caison Breakwaters on Rubble Foundation Exposed to Impulsive Loads

    DEFF Research Database (Denmark)

    Andersen, Lars; Burcharth, Hans F.; Andersen, Thomas Lykke

    2011-01-01

    Wave slamming on vertical breakwaters cause a sudden, impulsive load that may cause a caisson to slide on its foundation. Alternatively, geotechnical failure may occur in the subsoil. This paper investigates whether simple analytical solutions, accounting only for the sliding along the caisson...

  14. Construction, Maintenance and Repair as Elements in Rubble Mound Breakwater Design

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Rietveld, C.F.W.

    Very often rubble mound breakwater designs seem to be a result only of stability considerations corresponding to design wave conditions. Designers tend to put too little emphasis on practical problems related to construction, maintenance and repair. As is discussed in the paper due consideration ...

  15. Scale Effects Related to Small Physical Modelling of Overtopping of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Andersen, Thomas Lykke

    2007-01-01

    Most coastal structures suffer a certain degree of overtopping, because in most situations it is not economically feasible to construct coastal structures high enough to prevent wave overtopping. Certain functions of the breakwater impose restrictions to the allowable overtopping discharge in ord...

  16. Stability of Monolithic Rubble Mound Breakwater Crown Walls Subjected to Impulsive Loading

    DEFF Research Database (Denmark)

    Nørgaard, Jørgen Harck; Andersen, Lars Vabbersgaard; Andersen, Thomas Lykke;

    2012-01-01

    This paper evaluates the validity of a simple onedimensional dynamic analysis as well as a FEM model to determine the sliding of a rubble mound breakwater crown wall. The evaluation is based on a case example with real wave load time series and displacements measured from two-dimensional physical...

  17. Verification of Overall Safety Factors In Deterministic Design Of Model Tested Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, H. F.

    2001-01-01

    The paper deals with concepts of safety implementation in design. An overall safety factor concept is evaluated on the basis of a reliability analysis of a model tested rubble mound breakwater with monolithic super structure. Also discussed are design load identification and failure mode limit...

  18. COMPARISON OF SCOURS IN FRONT OF VERTICAL BREAKWATERS DUE TO REGULAR AND IRREGULAR WAVES

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this paper the scours of sand bed due to regular and irregular waves in front of vertical breakwaters, such as scouring patterns, scouring mechanisms, etc., are investigated. Thereby, the scours under the action of the two kinds of waves are compared connected.

  19. The wave motion over a submerged Jarlan-type perforated breakwater

    Institute of Scientific and Technical Information of China (English)

    LIU Yong; XIE Luqiong; ZHANG Zhehan

    2014-01-01

    The wave motion over a submerged Jarlan-type breakwater consisting of a perforated front wall and a sol-id rear wall was investigated analytically and experimentally. An analytical solution was developed using matched eigenfunction expansions. The analytical solution was confirmed by previously known solutions for single and double submerged solid vertical plates, a multidomain boundary element method solution, and experimental data. The calculated results by the analytical solution showed that compared with double submerged vertical plates, the submerged Jarlan-type perforated breakwater had better wave-absorbing performance and lower wave forces. For engineering designs, the optimum values of the front wall porosity, relative submerged depth of the breakwater, and relative chamber width between front and rear walls were 0.1-0.2, 0.1-0.2, and 0.3-0.4, respectively. Interchanging the perforated front wall and solid rear wall may have no effect on the transmission coefficient. However, the present breakwater with a seaside perforated wall had a lower reflection coefficient.

  20. Design Formulae for Hydraulic Stability and Structural Integrity of Dolos Breakwater Round-Heads

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Jensen, Jacob Birk; Liu, Z.

    1995-01-01

    A rational design of Dolos armour unit should incorporate both the hydraulic stability and the structural integrity. The previous tests performed by Aalborg University (AU) resulted in design formulae for the trunk of a 1:1.5 slope Dolos breakwater without superstructure including both...

  1. Validity of Simplified Analysis of Stability of Caison Breakwaters on Rubble Foundation Exposed to Impulsive Loads

    DEFF Research Database (Denmark)

    Andersen, Lars; Burcharth, Hans F.; Andersen, Thomas Lykke

    Excessive sliding and foundation failures are common failure modes for caisson breakwaters on rubble foundations. An accurate evaluation of these failure modes demands a dynamic analysis in the time domain, and due to the complexity of the material response, numerical solution methods must...

  2. Application of Reliability Analysis for Optimal Design of Monolithic Vertical Wall Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Sørensen, John Dalsgaard; Christiani, E.

    1995-01-01

    Reliability analysis and reliability-based design of monolithic vertical wall breakwaters are considered. Probabilistic models of some of the most important failure modes are described. The failures are sliding and slip surface failure of a rubble mound and a clay foundation. Relevant design...

  3. Reliability Based Optimal Design of Vertical Breakwaters Modelled as a Series System Failure

    DEFF Research Database (Denmark)

    Christiani, E.; Burcharth, H. F.; Sørensen, John Dalsgaard

    1996-01-01

    Reliability based design of monolithic vertical breakwaters is considered. Probabilistic models of important failure modes such as sliding and rupture failure in the rubble mound and the subsoil are described. Characterisation of the relevant stochastic parameters are presented, and relevant design...... variables are identified and an optimal system reliability formulation is presented. An illustrative example is given....

  4. Overtopping and Rear Slope Stability of Reshaping & Non-reshaping Berm Breakwaters

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Burcharth, H. F.

    2004-01-01

    Overtopping and rear slope stability of reshaping and non-reshaping berm breakwaters have been studied in a wave flume. A total of 695 tests have been performed to cover the influence of crest freeboard, crest width, berm width, berm elevation, stone size and sea state. Formula for average overto...

  5. Analyses of Stability of Caisson Breakwaters on Rubble Foundation Exposed to Impulsive Loads

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Andersen, Lars; Andersen, Thomas Lykke

    2009-01-01

    The paper deals with the analysis of the overall stability of caisson breakwaters exposed to impulsive wave loadings, in particular regarding sliding failure and failure in the subsoil. A comparison is made between prediction of sliding distances by a simple onedimensional (1-D) dynamic analysis ...

  6. On the Choice of Structure and Layout of Rubble Mound Breakwater Heads

    DEFF Research Database (Denmark)

    Maciñeira, Enrique; Burcharth, Hans F.

    2006-01-01

     The paper discusses the various functional, environmental and structural conditions to consider related to the choice of breakwater head type. Results from hydraulic model tests of rubble mound and caisson head solutions for the new deep water port at Punto Langosteira, La Coruña, Spain, are pre...

  7. 2-D Model Test Study of the Breakwater at Porto de Dande , Angola

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Ramirez, Jorge Robert Rodriguez; Burcharth, Hans F.

    This report deals with a two-dimensional model test study of the new breakwater at Porto de Dande, Angola. One cross-section was tested for stability and overtopping in various sea conditions. The length scale used for the model tests was 1:32. Unless otherwise specified all values given in this ...

  8. Physical modeling of long-wave run-up mitigation using submerged breakwaters

    Science.gov (United States)

    Lee, Yu-Ting; Wu, Yun-Ta; Hwung, Hwung-Hweng; Yang, Ray-Yeng

    2016-04-01

    Natural hazard due to tsunami inundation inland has been viewed as a crucial issue for coastal engineering community. The 2004 India Ocean tsunami and the 2011 Tohoku earthquake tsunami were caused by mega scale earthquakes that brought tremendous catastrophe in the disaster regions. It is thus of great importance to develop innovative approach to achieve the reduction and mitigation of tsunami hazards. In this study, new experiments have been carried out in a laboratory-scale to investigate the physical process of long-wave through submerged breakwaters built upon a mild slope. Solitary-wave is employed to represent the characteristic of long-wave with infinite wavelength and wave period. Our goal is twofold. First of all, through changing the positions of single breakwater and multiple breakwaters upon a mild slope, the optimal locations of breakwaters can be pointed out by means of maximum run-up reduction. Secondly, through using a state-of-the-art measuring technique Bubble Image Velocimetry, which features non-intrusive and image-based measurement, the wave kinematics in the highly aerated region due to solitary-wave shoaling, breaking and uprush can be quantitated. Therefore, the mitigation of long-wave due to the construction of submerged breakwaters built upon a mild slope can be evaluated not only for imaging run-up and run-down characteristics but also for measuring turbulent velocity fields due to breaking wave. Although we understand the most devastating tsunami hazards cannot be fully mitigated with impossibility, this study is to provide quantitated information on what kind of artificial coastal structure that can withstand which level of wave loads.

  9. Monte Carlo simulation model for economic evaluation of rubble mound breakwater protection in Harbors

    Institute of Scientific and Technical Information of China (English)

    Richard M. Males; Jeffrey A. Melby

    2011-01-01

    The US Army Corps of Engineers has a mission to conduct a wide array of programs in the arenas of water resources,including coastal protection.Coastal projects must be evaluated according to sound economic principles,and considerations of risk assessment and sea level change must be included in the analysis.Breakwaters are typically nearshore structures designed to reduce wave action in the lee of the structure,resulting in calmer waters within the protected area,with attendant benefits in terms of usability by navigation interests,shoreline protection,reduction of wave runup and onshore flooding,and protection of navigation channels from sedimentation and wave action.A common method of breakwater construction is the rubble mound breakwater,constructed in a trapezoidal cross section with gradually increasing stone sizes from the core out.Rubble mound breakwaters are subject to degradation from storms,particularly for antiquated designs with under-sized stones insufficient to protect against intense wave energy.Storm waves dislodge the stones,resulting in lowering of crest height and associated protective capability for wave reduction.This behavior happens over a long period of time,so a lifecycle model (that can analyze the damage progression over a period of years) is appropriate.Because storms are highly variable,a model that can support risk analysis is also needed.Economic impacts are determined by the nature of the wave climate in the protected area,and by the nature of the protected assets.Monte Carlo simulation (MCS)modeling that incorporates engineering and economic impacts is a worthwhile method for handling the many complexities involved in real world problems.The Corps has developed and utilized a number of MCS models to compare project alternatives in terms of their costs and benefits.This paper describes one such model,Coastal Structure simulation (CSsim) that has been developed specifically for planning level analysis of breakwaters.

  10. Particle swarm optimization based support vector machine for damage level prediction of non-reshaped berm breakwater

    Digital Repository Service at National Institute of Oceanography (India)

    Harish, N.; Mandal, S.; Rao, S.; Patil, S.G.

    breakwater. Soft computing tools like Artificial Neural Network, Fuzzy Logic, Support Vector Machine (SVM), etc, are successfully used to solve complex problems. In the present study, SVM and hybrid of Particle Swarm Optimization (PSO) with SVM (PSO...

  11. Report on 2D-model Testing of the Breakwater for a new Port of Puerto de la Cruz, Tenerife

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Meinert, Palle; Andersen, Thomas Lykke;

    The present report contains the results of a study of the stability and overtopping of the most exposed section of the breakwater protecting a new port at Puerto de la Cruz, Tenerife.......The present report contains the results of a study of the stability and overtopping of the most exposed section of the breakwater protecting a new port at Puerto de la Cruz, Tenerife....

  12. Partial Coefficient System for the Design of Monolithic Vertical Breakwaters Considering Sliding and Rupture Failure of the Foundation

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Christiani, Erik; Sørensen, John Dalsgaard

    1995-01-01

    The main object is to present a set of calibrated partial coefficients for monolithic vertical breakwater failure modes. A preliminary design of the monolithic breakwater will be considered, which will be designed from existing partial coefficients, documented in Eurocode 7 (1994). From this design...... is presented by the example of a translation slip failure involving kinematically correct slip surfaces and failure zones in friction based soil. A conventional quasi-static analysis is used....

  13. Hydraulic Response of Caisson Breakwaters in Multidirectional Breaking and Non-Breaking Waves

    DEFF Research Database (Denmark)

    Grønbech, J.; Kofoed, Jens Peter; Hald, Tue;

    1998-01-01

    induced loading and overtopping on caisson breakwaters situated in breaking seas. Regarding the wave forces only minor differences between breaking and non breaking waves in deep water were observed, and it was found that the prediction formula of Goda also seems to apply well for multidirectionally...... breaking waves at deep water. The study on wave overtopping showed that the 3D wave overtopping formula suggested by Franco et al., 1995b, predicts the wave overtopping reasonable well for both non breaking and breaking waves at deep water.......The present paper concerns the results and findings of a physical study on wave impacts on vertical caisson breakwaters situated in irregular, multidirectional breaking seas. The study has taken place as part of the framework programme "Dynamic of Structures" financially supported by the Danish...

  14. Comparison of New Large and Small Scale Overtopping Tests for Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Burcharth, Hans F.; Gironella, X.

    2011-01-01

    Many breakwaters are, due to functional requirements, designed for small wave overtopping discharges. From the EC-research projects OPTICREST and CLASH it is known that overtopping discharges determined from conventional Froude scale models of rubble mound breakwaters are smaller than measured...... in corresponding prototypes. The present study examines this scale effect by comparing overtopping discharges in small scale and large scale tests. The length scale ratio between the models was 5.7. The reason for using a large scale model instead of a prototype is the difficulties in accurate reproduction...... hardware and software. This demonstrates that, even under controlled conditions, it is very difficult to reproduce similar conditions. From the present test results it is concluded, despite the model effect, that a significant scale effect on small overtopping discharges exists also when wind effects...

  15. Transmitted and Reflected Coefficients for Horizontal or Vertical Plate Type Breakwater

    Institute of Scientific and Technical Information of China (English)

    WANG Ke; ZHANG Zhi-qiang; XU Wang

    2011-01-01

    Surface or submerged horizontal or vertical plate can be considered as a new concept breakwater. This paper investigates the wave-plate interaction of this type of breakwater by use of the boundary element method. The relationships of wave transmitted and reflected among plate thickness, submergence and length are carefully studied by numerical simulation. It is shown that: (1) The transmitted coefficients of submerged horizontal plate or vertical plate will become larger with the increase of plate thickness and reduce rapidly with the decrease of plate submergence. (2) Both surface horizontal and vertical plate are efficient for intermediate and short wave elimination, but vertical plate is more effective. (3)Submerged horizontal plate can act more effectively than submerged vertical plate does. With all wave frequencies, the vertical plate almost has no wave elimination effect.

  16. An Advanced Probabilistic Neural Network for the Design of Breakwater Armor Blocks

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this study, an advanced probabilistic neural network (APNN) method is proposed to reflect the global probability density function (PDF) by summing up the heterogeneous local PDF which is automatically determined in the individual standard deviation of variables. The APNN is applied to predict the stability number of armor blocks of breakwaters using the experimental data of van der Meer, and the estimated results of the APNN are compared with those of an empirical formula and a previous artificial neural network (ANN) model. The APNN shows better results in predicting the stability number of armor blocks of breakwater and it provided the promising probabilistic viewpoints by using the individual standard deviation in a variable.

  17. Artificial breakwaters as garbage bins: Structural complexity enhances anthropogenic litter accumulation in marine intertidal habitats.

    Science.gov (United States)

    Aguilera, Moisés A; Broitman, Bernardo R; Thiel, Martin

    2016-07-01

    Coastal urban infrastructures are proliferating across the world, but knowledge about their emergent impacts is still limited. Here, we provide evidence that urban artificial reefs have a high potential to accumulate the diverse forms of litter originating from anthropogenic activities around cities. We test the hypothesis that the structural complexity of urban breakwaters, when compared with adjacent natural rocky intertidal habitats, is a driver of anthropogenic litter accumulation. We determined litter abundances at seven sites (cities) and estimated the structural complexity in both urban breakwaters and adjacent natural habitats from northern to central Chile, spanning a latitudinal gradient of ∼15° (18°S to 33°S). Anthropogenic litter density was significantly higher in coastal breakwaters when compared to natural habitats (∼15.1 items m(-2) on artificial reefs versus 7.4 items m(-2) in natural habitats) at all study sites, a pattern that was temporally persistent. Different litter categories were more abundant on the artificial reefs than in natural habitats, with local human population density and breakwater extension contributing to increase the probabilities of litter occurrence by ∼10%. In addition, structural complexity was about two-fold higher on artificial reefs, with anthropogenic litter density being highest at intermediate levels of structural complexity. Therefore, the spatial structure characteristic of artificial reefs seems to enhance anthropogenic litter accumulation, also leading to higher residence time and degradation potential. Our study highlights the interaction between coastal urban habitat modification by establishment of artificial reefs, and pollution. This emergent phenomenon is an important issue to be considered in future management plans and the engineering of coastal ecosystems.

  18. Artificial breakwaters as garbage bins: Structural complexity enhances anthropogenic litter accumulation in marine intertidal habitats.

    Science.gov (United States)

    Aguilera, Moisés A; Broitman, Bernardo R; Thiel, Martin

    2016-07-01

    Coastal urban infrastructures are proliferating across the world, but knowledge about their emergent impacts is still limited. Here, we provide evidence that urban artificial reefs have a high potential to accumulate the diverse forms of litter originating from anthropogenic activities around cities. We test the hypothesis that the structural complexity of urban breakwaters, when compared with adjacent natural rocky intertidal habitats, is a driver of anthropogenic litter accumulation. We determined litter abundances at seven sites (cities) and estimated the structural complexity in both urban breakwaters and adjacent natural habitats from northern to central Chile, spanning a latitudinal gradient of ∼15° (18°S to 33°S). Anthropogenic litter density was significantly higher in coastal breakwaters when compared to natural habitats (∼15.1 items m(-2) on artificial reefs versus 7.4 items m(-2) in natural habitats) at all study sites, a pattern that was temporally persistent. Different litter categories were more abundant on the artificial reefs than in natural habitats, with local human population density and breakwater extension contributing to increase the probabilities of litter occurrence by ∼10%. In addition, structural complexity was about two-fold higher on artificial reefs, with anthropogenic litter density being highest at intermediate levels of structural complexity. Therefore, the spatial structure characteristic of artificial reefs seems to enhance anthropogenic litter accumulation, also leading to higher residence time and degradation potential. Our study highlights the interaction between coastal urban habitat modification by establishment of artificial reefs, and pollution. This emergent phenomenon is an important issue to be considered in future management plans and the engineering of coastal ecosystems. PMID:27149151

  19. Spatial Coherence of Impact Pressures at a Vertical Breakwater in Multidirectional Seas

    DEFF Research Database (Denmark)

    Sauer, W.; Löffler, A.; Kortenhaus, A.;

    " (LSF) includes the possibility for researchers to work at selected European large-scale facilities. Within this activity the project "Spatial coherence of impact pressures at a vertical breakwater in multidirectional seas" was founded and could therefore be performed by the University of Bologna...... (DISTART Idraulica, Italy [UoB]), Aalborg University (Hydraulics and Coastal Engineering Laboratory, Denmark [AU]) and Technical University of Braunschweig (Leichtweiss-Institut, Germany [LWI])....

  20. Simulating three dimensional wave run-up over breakwaters covered by antifer units

    Directory of Open Access Journals (Sweden)

    Najafi-Jilani A.

    2014-06-01

    Full Text Available The paper presents the numerical analysis of wave run-up over rubble-mound breakwaters covered by antifer units using a technique integrating Computer-Aided Design (CAD and Computational Fluid Dynamics (CFD software. Direct application of Navier-Stokes equations within armour blocks, is used to provide a more reliable approach to simulate wave run-up over breakwaters. A well-tested Reynolds-averaged Navier-Stokes (RANS Volume of Fluid (VOF code (Flow-3D was adopted for CFD computations. The computed results were compared with experimental data to check the validity of the model. Numerical results showed that the direct three dimensional (3D simulation method can deliver accurate results for wave run-up over rubble mound breakwaters. The results showed that the placement pattern of antifer units had a great impact on values of wave run-up so that by changing the placement pattern from regular to double pyramid can reduce the wave run-up by approximately 30%. Analysis was done to investigate the influences of surface roughness, energy dissipation in the pores of the armour layer and reduced wave run-up due to inflow into the armour and stone layer.

  1. VIBRATING-UPLIFT ROCKING MOTION OF CAISSON BREAKWATERS UNDER VARIOUS BREAKING WAVE IMPACT FORCES

    Institute of Scientific and Technical Information of China (English)

    WANG Yuan-zhan; ZHOU Zhi-rong; YANG Hai-dong

    2005-01-01

    Overturning is one of principal failure types of caisson breakwaters and is an essential content of stability examination in caisson breakwater design. The mass-springdashpot model of caisson-foundation system is used to simulate the vibrating-uplift rocking motion of caisson under various types of breaking wave impact forces, i.e., single peak impact force, double peak impact force, and shock-damping oscillation impact force. The effects of various breaking wave types and the uplift rocking motion on dynamic response behaviors of caisson breakwaters are investigated. It is shown that the dynamic responses of a caisson are significantly different under different types of breaking wave impact forces even when the amplitudes of impact forces are equal. Though the rotation of a caisson is larger due to the uplift rocking motion, the displacement, the sliding force and the overturning moment of the caisson are significantly reduced. It provides the theoretical base for the design idea that the uplift rocking motion of caisson is allowed in design.

  2. Vibrating-Sliding Motion of Caisson Breakwaters Under Various Breaking Wave Impact Forces

    Institute of Scientific and Technical Information of China (English)

    王元战; 于红霞

    2003-01-01

    Sliding is one of the principal failure types of caisson breakwaters and is an essential content of stability examination in caisson breakwater design. Herein, the mass-spring-dashpot model of caisson-base system is used to simulate the vibrating-sliding motion of the caisson under various types of breaking wave impact forces, i.e., single peak impact force, double peak impact force, and shock-damping oscillation impact force. The effects of various breaking wave impacts and the sliding motion on the dynamic response behaviors of caisson breakwaters are investigated and the calculation of relevant system parameters is discussed. It is shown that the dynamic responses of the caisson are significantly different under different types of breaking wave impact forces even when the amplitudes of impact forces are equal. The amplitude of dynamic response of the caisson is lower under single peak impact excitation than that under double peak impact or shock-damping oscillation impact excitation. Though the displacement of the caisson is large due to sliding, the rotation, the sliding force and the overturning moment of the caisson are significantly reduced.

  3. Stability formula for armor units to tsunami on rubble mound breakwater

    International Nuclear Information System (INIS)

    The mechanism of the failure of armor units of the rubble mound breakwater due to tsunami was investigated based on the experiments. Tsunamis with leading wave, negative leading wave and soliton fissions were the target tsunamis in the present work. Two different sizes of the wave flumes were used in the experiments. A shorter wave flume is 76m long, 1.2m deep and 0.90m wide and the longer one 205m long, 6.0m deep and 3.4m wide. The mass of the armor unit used ranges from 14g, 30g, 50g, 112g, 240g to 400g. The stability formula was derived from the balance of the fluid force acting armor units and the resistance force of the armor unit in the armor layer. The two coefficients such as the drag coefficient of the armor unit and the friction coefficient are determined to give the stability condition. The relationship between the mass of armor units and the maximum velocity on the crest of the rubble mound breakwater was obtained to determine the conditions of no damage of the armor layer. The numerical simulation method to estimate the velocity on the crest of the rubble mound breakwater was described in the present work. The numerical simulation results were verified with the experimental results of the time histories of the water depth and the horizontal component of the velocity and a good agreements was confirmed. (author)

  4. Wave transmission over permeable submerged breakwaters; Transmision del oleaje en rompeolas sumergidos permeables

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz-y-Zurvia-Flores, Jaime Roberto; Fragoso-Sandoval, Lucio [Instituto Politecnico Nacional(Mexico)

    2008-10-15

    The permeable submerged breakwaters represent a coastal protection alternative, where some degree of wave energy transmission is acceptable. Such would be the case of tourist beach protection in Mexico. In previous researches, like those performed by D'Angremond et al. (1996), Seabrook and Hall (1998), and Briganti et al. (2003), the empirical formulas developed, give only some limited information over the spatial distribution of wave energy over the structure. Therefore, a decision was made to conduct a study on a reduced physical model of a permeable submerged breakwater based on the results presented by those researchers and with possible applications. Therefore this paper presents the development of a study of wave transmission over permeable submerged breakwaters performed in a reduced physical model of different sections of a submerged rockfill breakwater of the trapezoidal type. This was done in a narrow wave flume with a hydraulic irregular wave generator controlled by a computer that was used to generate and to reproduce different types of irregular waves to be used in the tests. It also has a wave meter with four sensors, and they are connected to a computer in order to process the wave data. The main objective of the study was to determine in an experimental way the influence of the several parameters of submerged breakwater over the wave transmission coefficient. Our experimental results were comparable to those obtained by D'Angremond et al. (1996) and Seabrook and Hall (1998). The results show that the sumerged breakwater parameters of most influence over the wave transmission coefficient were relative submergence and the relative width crest of the sumerged breakwater, and that the formula by Seabrook and Hall correlates best with our results. [Spanish] Los rompeolas sumergidos permeables representan actualmente una alternativa de proteccion de costas, donde un cierto grado de transmision de energia del oleaje es aceptable, como seria el

  5. Estimation of Partial Safety Factors and Target Failure Probability Based on Cost Optimization of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Kim, Seung-Woo; Suh, Kyung-Duck; Burcharth, Hans F.

    2010-01-01

    The breakwaters are designed by considering the cost optimization because a human risk is seldom considered. Most breakwaters, however, were constructed without considering the cost optimization. In this study, the optimum return period, target failure probability and the partial safety factors...... were evaluated by applying the cost optimization to the rubble mound breakwaters in Korea. The applied method was developed by Hans F. Burcharth and John D. Sorensen in relation to the PIANC Working Group 47. The optimum return period was determined as 50 years in many cases and was found as 100 years...... of the national design standard and then the overall safety factor is calculated as 1.09. It is required that the nominal diameter and weight of armor are respectively 9% and 30% larger than those of the existing design method. Moreover, partial safety factors considering the cost optimization were compared...

  6. Experimental and Theoretical Investigation of Wave Forces on A Partially-Perforated Caisson Breakwater with A Rock-Filled Core

    Institute of Scientific and Technical Information of China (English)

    LIU Yong; LI Yu-cheng; TENG Bin; JIANG Jun-jie

    2006-01-01

    The total horizontal and vertical forces acting on a partially-perforated caisson breakwater and their phase difference are investigated in this study. The perforated breakwater sits on the rubble filled foundation, and has a rock-filled core. An analytical solution is developed based on the eigenfunction expansion and matching method to solve the wave field around the breakwater. The finite element method is used for simulating the wave-induced flow in the rubble-filled foundation. Experiments are also conducted to study the wave forces on the perforated caissons. Numerical predictions of the present model are compared with experimental results. The phase differences between the total horizontal and vertical forces are particularly analyzed by means of experimental and numerical results. The major factors that affect the wave forces are examined.

  7. Consolidation and dynamics of 3D unsaturated porous seabed under rigid caisson breakwater loaded by hydrostatic pressure and wave

    Institute of Scientific and Technical Information of China (English)

    YE JianHong; JENG DongSheng; CHAN A H C

    2012-01-01

    In this study,based on the dynamic Biot's theory "u-p" approximation,a 3D finite element method (FEM) numerical soil model is developed,in which the Generalized Newmark-β method is adopted to determine the time integration.The developed 3D FEM soil model is a part of the coupled model PORO-WSSI 3D for 3D wave-seabed-marine structures interaction problem,and is validated by the analytical solution proposed by Wang (2000) for a laterally infinite seabed loaded by a uniform force.By adopting the developed 3D soil model,the consolidation of seabed under a caisson breakwater and hydrostatic pressure is investigated.The numerical results show that the caisson breakwater built on seabed has very significant effect on the stresses/displacements fields in the seabed foundation after the transient deformation and primary consolidation are completed.The parametric study indicates that the Young's modulus E of seabed is the most important parameter to affect the settlement of breakwater,and the displacement fields in seabed foundation.Taking the consolidation status as the initial condition,the interaction between ocean wave,caisson breakwater and seabed foundation is briefly investigated.The 3D ocean wave is determined by solving the Navier-Stokes equations with finite volume method (FVM).The numerical results indicate that there is intensive interaction between ocean wave,caisson breakwater and seabed foundation; and the breakwater indeed can effectively block the wave energy propagating to the coastline.

  8. 2-D Physical Modeling to Measure the Effectiveness of Perforated Skirt Breakwater for Short-Period Waves

    Directory of Open Access Journals (Sweden)

    Harman Ajiwibowo

    2011-04-01

    Full Text Available The effectiveness of a breakwater can be measured by quantifying the transmission coefficient (KT. The smaller the coefficient, the better the performance of the breakwater. A physical modeling on the proposed breakwater was conducted to identify the coefficient of Perforated Skirt Breakwater (PSB. The PSB model was tested in 2-D wave flume at Ocean Wave Research Laboratory FTSL ITB, to obtain the effectiveness of PSB for short-period waves (prototype periods, Tp= 4 second and smaller. The scaling of PSB models applies the principle of Froude Similarity, where the Froude number in model equals to the Froude number in prototype (Frm=Frp. The flume is equipped with 5 resistance-type wave probes and 8-channel DAS (Data Acquisition System. Wave heights (H and wave periods (T data were observed both manually by visual observation and wave probes readings (processed later with method of “zero mean up-crossing” technique. The incoming wave heights (Hi and transmitted wave heights (Ht were measured and processed to obtain the transmission coefficient (KT. The relationships between KT and non-dimensional variables (skirt draft / incident wave height, S/Hi are analyzed and the calculated effectiveness of the PSB for varied environmental condition is obtained to be up to 70%.Abstract. The effectiveness of a breakwater can be measured by quantifying the transmission coefficient (KT. The smaller the coefficient, the better the performance of the breakwater. A physical modeling on the proposed breakwater was conducted to identify the coefficient of Perforated Skirt Breakwater (PSB. The PSB model was tested in 2-D wave flume at Ocean Wave Research Laboratory FTSL ITB, to obtain the effectiveness of PSB for short-period waves (prototype periods, Tp= 4 second and smaller. The scaling of PSB models applies the principle of Froude Similarity, where the Froude number in model equals to the Froude number in prototype (Frm=Frp. The flume is equipped with 5

  9. RESEARCH ON WAVE FORCES ACTING ON THE UNIT LENGTH OF A VERITICAL BREAKWATER BY TESTS AND A NUMERICAL MODEL

    Institute of Scientific and Technical Information of China (English)

    HU Jin-peng; YU Yu-xiu; ZHU Liang-sheng

    2006-01-01

    Comprehensive 3D model tests and numerical simulation were performed to study the effects of wave obliquity and multidirectionality on the wave forces acting on vertical breakwaters.The variation of wave forces acting on the unit length of a breakwater was analyzed, and the results were compared with Goda's formula.A numerical model based on a short-crest wave system was used to model regular wave forces for practical use, which showed good results for those waves with small incident angles.

  10. Reflection of Oblique Incident Waves by Breakwaters with Partially-Perforated Wall

    Institute of Scientific and Technical Information of China (English)

    李玉成; 刘洪杰; 滕斌; 孙大鹏

    2002-01-01

    The reflection of oblique incident waves from breakwaters with a partially-perforated front wall is investigated. Thefluid domain is divided into two sub-domains and the eigenfunction expansion method is applied to expand velocity poten-tials in each domain. In the eigen-expansion of the velocity potential, evanescent waves are included. Numerical resultsof the present model are compared with experimental data. The effect of porosity, the relative chamber width, the relativewater depth in the wave absorbing chamber and the water depth in front of the structure are discussed.

  11. Development of a Partial Coefficient System for the Design of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, H. F.

    Subgroup F is the last of the subgroups formed under the PIANC II Working Group 12 on Rubble Mound Structures. The terms of reference of subgroup F are to propose safety guidelines for rubble mound breakwaters including evaluation of the safety levels inherent in conventionally designed existing...... coefficient system which is simple to apply and well known from other fields of civil engineering. This report presents a proposal for safety guidelines supported by a presentation of the main problems which have been considered together with the outcome of the related calculations. The limitations...

  12. Wave Forces and Overtopping on Crown Walls of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Pedersen, Jan

    in the coastal laboratory at Aalborg University. Based on analyses of experimental data a design method for assessing the maximum wave forces on the vertical face of the crown wall structures has been developed as well as new and more versatile design equation for the related overtopping discharges...... of rubble mound breakwater crown walls. This background motivated the initialization of the present study on wave imposed forces and wave overtopping on crown wall structures. The two subjects where investigated through an excessive parametric model study involving more than 370 long duration test series...

  13. Estimation of Wave Conditions Along a New Breakwater for the Hanstholm Harbour, Using the Numerical Model MILDwave

    DEFF Research Database (Denmark)

    Stratigaki, Vasiliki; Troch, Peter; Margheritini, Lucia;

    2012-01-01

    the wave conditions along the planned breakwater, close to the Danish Wave Energy Centre (DanWEC). Numerical results of the wave climate in the study area are presented here, including validation of the performance of the wave breaking module implemented in MILDwave, showing very good agreement...

  14. Computer aided optimum design of rubble-mound breakwater cross-sections: manual of the RUMBA computer package, release 1

    NARCIS (Netherlands)

    De Haan, W.

    1989-01-01

    The computation of the optimum rubble-mound breakwater crosssection is executed on a micro-computer. The RUMBA computer package consists of two main parts: the optimization process is executed by a Turbo Pascal programme, the second part consists of editing functions written in AutoLISP. AutoLISP is

  15. Model Testing and Reliability Evalution of the New Deepwater Breakwater at La Coruña, Spain

    DEFF Research Database (Denmark)

    Burcharth, Hans Falk; Maciñeira, Enrique; Canalejo, Pedro

    2003-01-01

    A new deepwater port development at Punta Langosteira near La Coruña is under design. Shelter is provided by a 2 km long rubble mound breakwater fully exposed to Atlantic waves. Max. water depth is 45 m, crownwall crest level is + 25 m and main armour blocks are 150 t cubes. Moorings for oil...

  16. On Methods of Establishing Design Diagrams for Structural Integrity of Slender Complex Types of Breakwater Armour Units

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Howell, Gary J.

    1988-01-01

    Many of the recent dramatic failures of a number of large rubble mound breakwaters armoured with Dolosse and Tetrapods were caused by breakage of the concrete armour units. Breakage took place before the hydraulic stability of intact units in the armour layers expired. Thus there was not a balance...

  17. Experimental Study on the Effects of A Breakwater on Wave Field Characteristics

    Institute of Scientific and Technical Information of China (English)

    尹彰; 周宗仁; 黄伟柏

    2000-01-01

    Studies on the possible effects of a detached breakwater on the characteristics of the wave field are carried out experimentally. A serpentine wave generator is used to generate both uni- and multi-directional waves. Characteristics of the wave fields analyzed here include the wave field directionality, and the probability distributions of surface elevations and of the wave heights. Owing to the presence of the breakwater, waves outside the harbour are found to be reflected with, however, concentrated energy within the harbour entrance. In general wave heights can be approximated with a Rayleigh distribution, with occasional deviations from the theory. This occurs more frequently for waves with higher peak frequency values than for those with lower values both for uni- and multi-directional waves. Surface elevations can be approximated with the Gaussian model although the Edgeworth′s form of the type A Gram-Charlier series expansions would yield better fits. Wave directionality is found to have no discernible effects on the statistical characteristics of the wave field.

  18. Modelling of Random Waves over Submerged Breakwaters and Its Application to Reflection Estimation

    Institute of Scientific and Technical Information of China (English)

    SHIH Ruey-Syan; CHOU Chung-Ren; YIM John-Z

    2006-01-01

    Reflection and transmission of random waves from submerged obstacles under various conditions are investigated in this study by means of the boundary element method. The algorithm is based on the Lagrangian description with finite difference adopted for the approximation of time derivative. The accuracy of the model is confirmed by a previous study of the transmission of irregular waves in a water tank without any obstacle, under which sets of submerged breakwaters are located. To reduce the effect of reflection from the wall, a sponge zone is employed at the other end of the flume as an artificial absorbing beach. The power spectrum of Bretschneider-Mitsuyasu type defined by significant wave height, H1/3, and period, T1/3, is employed for the condition of incident waves chosen for the generation of irregular waves. Time histories of water elevations are measured with numerous pseudo wave gages on the free water surface. With reference to the method for the estimation of irregular incident and reflected waves in random sea presented by Goda and Suzuki (1976), the dissipation efficiency of the breakwaters is investigated. Gauges in different positions are tested for their suitability for the estimation of reflection coefficients for irregular waves. The present results demonstrate the effectiveness of the estimation of reflection coefficient for random waves, and indicate the feasibility of the numerical model.

  19. Numerical analyses of caisson breakwaters on soft foundations under wave cyclic loading

    Science.gov (United States)

    Wang, Yuan-zhan; Yan, Zhen; Wang, Yu-chi

    2016-03-01

    A caisson breakwater is built on soft foundations after replacing the upper soft layer with sand. This paper presents a dynamic finite element method to investigate the strength degradation and associated pore pressure development of the intercalated soft layer under wave cyclic loading. By combining the undrained shear strength with the empirical formula of overconsolidation clay produced by unloading and the development model of pore pressure, the dynamic degradation law that describes the undrained shear strength as a function of cycle number and stress level is derived. Based on the proposed dynamic degradation law and M-C yield criterion, a dynamic finite element method is numerically implemented to predict changes in undrained shear strength of the intercalated soft layer by using the general-purpose FEM software ABAQUS, and the accuracy of the method is verified. The effects of cycle number and amplitude of the wave force on the degradation of the undrained shear strength of the intercalated soft layer and the associated excess pore pressure response are investigated by analyzing an overall distribution and three typical sections underneath the breakwater. By comparing the undrained shear strength distributions obtained by the static method and the quasi-static method with the undrained shear strength distributions obtained by the dynamic finite element method in the three typical sections, the superiority of the dynamic finite element method in predicting changes in undrained shear strength is demonstrated.

  20. Numerical Analyses of Caisson Breakwaters on Soft Foundations Under Wave Cyclic Loading

    Institute of Scientific and Technical Information of China (English)

    王元战; 焉振; 王禹迟

    2016-01-01

    A caisson breakwater is built on soft foundations after replacing the upper soft layer with sand. This paper presents a dynamic finite element method to investigate the strength degradation and associated pore pressure development of the intercalated soft layer under wave cyclic loading. By combining the undrained shear strength with the empirical formula of overconsolidation clay produced by unloading and the development model of pore pressure, the dynamic degradation law that describes the undrained shear strength as a function of cycle number and stress level is derived. Based on the proposed dynamic degradation law and M-C yield criterion, a dynamic finite element method is numerically implemented to predict changes in undrained shear strength of the intercalated soft layer by using the general-purpose FEM software ABAQUS, and the accuracy of the method is verified. The effects of cycle number and amplitude of the wave force on the degradation of the undrained shear strength of the intercalated soft layer and the associated excess pore pressure response are investigated by analyzing an overall distribution and three typical sections underneath the breakwater. By comparing the undrained shear strength distributions obtained by the static method and the quasi-static method with the undrained shear strength distributions obtained by the dynamic finite element method in the three typical sections, the superiority of the dynamic finite element method in predicting changes in undrained shear strength is demonstrated.

  1. Backwash process of marine macroplastics from a beach by nearshore currents around a submerged breakwater.

    Science.gov (United States)

    Kataoka, Tomoya; Hinata, Hirofumi; Kato, Shigeru

    2015-12-30

    A key factor for determining the residence time of macroplastics on a beach is the process by which the plastics are backwashed offshore (backwash process). Here, we deduced the backwash process of plastic fishing floats on Wadahama Beach based on the analysis of two-year mark-recapture experiments as well as nearshore current structures revealed by sequential images taken by za webcam installed at the edge of a cliff behind the beach. The analysis results revealed the occurrence of a combination of offshore currents and convergence of alongshore currents in the surf zone in storm events around a submerged breakwater off the northern part of the beach, where 48% of the backwashed floats were last found. We conclude that the majority of the floats on the beach were transported alongshore and tended to concentrate in the convergence zone, from where they were backwashed offshore by the nearshore currents generated in the events. PMID:26561445

  2. Pressure-induced forces and shear stresses on rubble mound breakwater armour layers in regular waves

    DEFF Research Database (Denmark)

    Jensen, Bjarne; Christensen, Erik Damgaard; Sumer, B. Mutlu

    2014-01-01

    measurements in the core material: (1) core material with an idealized armour layer made out of spherical objects that also allowed for detailed velocity measurements between and above the armour, and (2) core material with real rock armour stones. The same core material was applied through the entire......This paper presents the results from an experimental investigation of the pressure-induced forces in the core material below the main armour layer and shear stresses on the armour layer for a porous breakwater structure. Two parallel experiments were performed which both involved pore pressure...... pressure gradients were found which exerted a lift force up to ≈60% of the submerged weight of the core material. These maximum outward directed pressure gradients were linked to the maximum run-down event and were in general situated at, or slightly below, the maximum run-down level. Detailed velocity...

  3. Damage pattern and damage progression on breakwater roundheads under multidirectional waves

    DEFF Research Database (Denmark)

    Comola, F.; Andersen, Thomas Lykke; Martinelli, L.;

    2014-01-01

    characteristics. The damage progression is observed dependent on significant wave height and peak wave period, but not on the directional spreading and the spectral width of the incident waves. Combining the results of both damage pattern and damage progression, a stability formula for the distribution of damage......An experimental model test study is carried out to investigate damage pattern and progression on a rock armoured breakwater roundhead subjected to multidirectional waves. Concerning damage pattern, the most critical sector is observed to shift leeward with increasing wave period. Taking angles...... relative to mean wave direction, the critical sector is observed in the sector 10°–55° for short waves and in the sector 100°–145° for long waves. A probabilistic approach is developed to predict for one typical roundhead geometry the damage distribution depending on the incomingwaves and structural...

  4. Coastal defence through low crested breakwater structures: jumping out of the frying pan into the fire?

    Science.gov (United States)

    Munari, Cristina; Corbau, Corinne; Simeoni, Umberto; Mistri, Michele

    2011-08-01

    The Adriatic coast of Punta Marina (Ravenna) is protected by 3-km long low crested breakwater structures (LCSs). Through a 3-years long multidisciplinar study, we assessed the impact of such defensive structures on environmental and biological condition. LCSs create pools where conditions are very different from the surrounding nearshore system. Mechanical disturbance by currents and waves varied greatly in intensity and frequency between seaward and landward sides of the structures. Sedimentary budget was positive at the landward side, but it was due to a gain on the seafloor and not on the emerged beach. The budget at seaward was negative. LCSs determine differences in benthic assemblages, alter the seasonal pattern of communities, and modify seasonal fluctuations of animal assemblages. Landward sheltered areas can be seen as "lagoonal island" surrounded by a "sea of marine habitat". Differences in ecological quality status, obtained through M-AMBI, are due to the sum of these factors. PMID:21722927

  5. Backwash process of marine macroplastics from a beach by nearshore currents around a submerged breakwater.

    Science.gov (United States)

    Kataoka, Tomoya; Hinata, Hirofumi; Kato, Shigeru

    2015-12-30

    A key factor for determining the residence time of macroplastics on a beach is the process by which the plastics are backwashed offshore (backwash process). Here, we deduced the backwash process of plastic fishing floats on Wadahama Beach based on the analysis of two-year mark-recapture experiments as well as nearshore current structures revealed by sequential images taken by za webcam installed at the edge of a cliff behind the beach. The analysis results revealed the occurrence of a combination of offshore currents and convergence of alongshore currents in the surf zone in storm events around a submerged breakwater off the northern part of the beach, where 48% of the backwashed floats were last found. We conclude that the majority of the floats on the beach were transported alongshore and tended to concentrate in the convergence zone, from where they were backwashed offshore by the nearshore currents generated in the events.

  6. The force of oblique incident wave on the breakwater with a partially perforated wall

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Wave forces induced by the interaction between the oblique incident wave and the breakwater with a partially perforated front wall is investigated. The fluid domain is divided into two sub-domains and the eigen-function expansion method is applied to expanding velocity potentials in each domain. In the eigen-expansion of the velocity potential, evanescent waves are included. Numerical results of the present model are compared with other theories and a good agreement can be found between them. Experimental data have been compared with the present theoretical results. The effect of the traverse wall on wave forces has been discussed in detail. On the basis of the linear wave theory, it is shown that in the range of engineering practice, the incident angle of wave has small influence on wave forces on the unit length of perforated caisson.

  7. PREDICTION OF HYDRODYNAMIC COEFFICIENTS OF PERMEABLE PANELED BREAKWATER USING ARTIFICIAL NEURAL NETWORKS

    Directory of Open Access Journals (Sweden)

    Mona A. Hagras

    2013-08-01

    Full Text Available In the present study, Artificial Neural Networks (ANNs with different topologies have been evaluated to be used to predict hydrodynamic coefficients of permeable paneled breakwater. Two neural network models are constructed, one to predict wave transmission coefficient (Kt and another for the prediction of wave reflectioncoefficient (Kr. Back propagation algorithm was used to train a multi-layer feed-forward network (Levenberg Marquardt algorithm. The capability of ANN topologies to estimate these coefficients is evaluated using the Mean Squared Error (MSE. Based on training patterns of different ANNs, a 5-7-1 topology has been selected topredict both coefficients. The results of the developed ANN models proved that this technique is reliable in such field. A good match between the measured and predicted values was observed with correlation values varying in the range (0.9508-0.9805 for the training set and (0.9159-0.9877 for the testing set.

  8. Spatial variability in community composition on a granite breakwater versus natural rocky shores: lack of microhabitats suppresses intertidal biodiversity.

    Science.gov (United States)

    Aguilera, Moisés A; Broitman, Bernardo R; Thiel, Martin

    2014-10-15

    Strong differences have been observed between the assemblages on artificial reefs and on natural hard-bottom habitats worldwide, but little is known about the mechanisms that cause contrasting biodiversity patterns. We examined the influence of spatial attributes in relation to both biogenic and topographic microhabitats, in the distribution and composition of intertidal species on both artificial and natural reefs. We found higher small-scale spatial heterogeneity on the natural reef compared with the study breakwater. Species richness and diversity were associated with a higher availability of crevices, rock pools and mussels in natural habitats. Spatial distribution of certain grazers corresponded well with the spatial structure of microhabitats. In contrast, the lack of microhabitats on the breakwater resulted in the absence of several grazers reflected in lower species richness. Biogenic and topographic microhabitats can have interactive effects providing niche opportunities for multiple species, explaining differences in species diversity between artificial versus natural reefs. PMID:25103901

  9. Effect of Short-Crestedness and Obliquity on Non-Breaking and Breaking Wave Forces Applied to Vertical Caisson Breakwaters

    DEFF Research Database (Denmark)

    Martinelli, Luca; Lamberti, Alberto; Frigaard, Peter

    2007-01-01

    This paper addresses wave forces applied to vertical caisson breakwaters. Design diagrams are proposed to evaluate the reduction of the breaker wave force with increasing horizontal length of the units. A model in 1:100 scale of a typical Italian vertical breakwater was tested under...... multidirectional waves, causing mainly spilling and occasionally plunging breakers, in the CRF-LSF (Wallingford, UK) wave basin. Seven adjacent modules were instrumented with synchronized force transducers. Pulsating and breaking loads were distinguished on the basis of the frequency content and the spatial...... correlation of the force per unit length was fitted to a single or a double bell shaped distribution. The experimental autocorrelation function for pulsating loads agrees with theoretical solutions; for breaking waves it has a Taylor microscale which is approximately 7% of wavelength, only slightly dependent...

  10. Effect of water depth on the performance of intelligent computing models in predicting wave transmission of floating pipe breakwater.

    Digital Repository Service at National Institute of Oceanography (India)

    Patil, S.G.; Mandal, S.; Hegde, A.V.

    , wave heights ranging from 0.030 m to 0.18m, and wave periods ranging from 1.2 sec to 2.2 sec. The widths of the breakwater were decided by varying the W / L values from 0.4 to 2.65. The transmitted wave heights on the leeside of the breakwater... · Number 2 · 2014 Figure 1. Typical Experimental set up of HIMMFPB Wave-specific parameters Experimental range Incident wave height, iH (mm) 30, 60, 90, 120, 150, 180 Wave period, T (sec) 1.2, 1.4, 1.6, 1.8, 2.0, 2.2 Depth of water, d (mm) 400, 450...

  11. A non-intrusive and continuous-in-space technique to investigate the wave transformation and breaking over a breakwater

    Directory of Open Access Journals (Sweden)

    Ferrari Simone

    2016-01-01

    Full Text Available To design longshore breakwaters, the evaluation of the wave motion transformations over the structures and of the energy they are able to absorb, dissipate and reflect is necessary. To characterize features and transformations of monochromatic wave trains above a breakwater, both submerged and emerged, we have designed and developed a non-intrusive and continuous-in-space technique, based on Image Analysis, and carried out an experimental campaign, in a laboratory flume equipped with a wave-maker, in order to test it. The investigation area was lighted with a light sheet and images were recorded by a video-camera. The working fluid was seeded with non buoyant particles to make it bright and clearly distinct from dark background and breakwater. The technique, that is based on a robust algorithm to identify the free surface, has showed to properly work also in prohibitive situations for traditional resistive probes (e.g., very shallow waters and/or breaking waves and to be able to measure the free surface all over the investigation field in a non-intrusive way. Two kind of analysis were mainly performed, a statistical and a spectral one. The peculiarities of the measurement technique allowed to describe the whole wave transformation and to supply useful information for design purposes.

  12. Effects of vertical wall and tetrapod weights on wave overtopping in rubble mound breakwaters under irregular wave conditions

    Directory of Open Access Journals (Sweden)

    Park Sang Kil

    2014-12-01

    Full Text Available Rubble mound breakwaters protect the coastal line against severe erosion caused by wave action. This study examined the performance of different sizes and properties (i.e. height of vertical wall and tetrapod size of rubble mound breakwaters on reducing the overtopping discharge. The physical model used in this study was derived based on an actual rubble mound in Busan Yacht Harbor. This research attempts to fill the gap in practical knowledge on the combined effect of the armor roughness and vertical wall on wave overtopping in rubble mound breakwaters. The main governing parameters used in this study were the vertical wall height, variation of the tetrapod weights, initial water level elevation, and the volume of overtopping under constant wave properties. The experimental results showed that the roughness factor differed according to the tetrapod size. Furthermore, the overtopping discharge with no vertical wall was similar to that with relatively short vertical walls ( 1 γv = 1. Therefore, the experimental results highlight the importance of the height of the vertical wall in reducing overtopping discharge. Moreover, a large tetrapod size may allow coastal engineers to choose a shorter vertical wall to save cost, while obtaining better performance.

  13. Assessing shoreline response to three submerged breakwaters at Kerteh Bay, Terengganu, Malaysia using Landsat imagery

    International Nuclear Information System (INIS)

    As part of a project to determine the exact structural and environmental parameters governing the mode and magnitude of salient formation behind a submerged breakwater, a remote sensing technique is being adopted to assess the extent of erosion/accretion at Kerteh Bay, T errengganu, Malaysia. Multi-temporal Landsat satellite images of coarse resolution for the years of 1994, 2000, 2006, 2009 and 2012 were acquired for this purpose. The images were subsets divided into smaller areas of interest and classified using supervised classification of support vector machine. The classified image is then vectorized to extract shoreline based on waterline in each of the subset rasters images. Tidal correction were adopted to correct the waterline/shoreline to the mean sea level (MSL) datum. Comparison of corrected shorelines was carried to obtain the extent of erosion/accretion at the Kerteh Bay, Terrenganu, Malaysia. It was observed that substantial accretion was observed between the years 1994-2006 at the upper part of the study area, the part between northern part and the southern part also experienced accretion but not as much as compared to northern part for the same year. Erosion was noted between the years 2006-2012 for all of the areas of the study area but the rate slowed down between the years 2009-2012 for all the areas. Slope estimated from the imageries were compared with in situ slope of the same area, this served as a validation for the method used

  14. Prediction of Seaward Slope Recession in Berm Breakwaters Using M5' Machine Learning Approach

    Institute of Scientific and Technical Information of China (English)

    Alireza Sadat HOSSEINI; Mehdi SHAFIEEFAR

    2016-01-01

    In the design process of berm breakwaters, their front slope recession has an inevitable rule in large number of model tests, and this parameter being studied. This research draws its data from Moghim’s and Shekari’s experiment results. These experiments consist of two different 2D model tests in two wave flumes, in which the berm recession to different sea state and structural parameters have been studied. Irregular waves with a JONSWAP spectrum were used in both test series. A total of 412 test results were used to cover the impact of sea state conditions such as wave height, wave period, storm duration and water depth at the toe of the structure, and structural parameters such as berm elevation from still water level, berm width and stone diameter on berm recession parameters. In this paper, a new set of equations for berm recession is derived using the M5' model tree as a machine learning approach. A comparison is made between the estimations by the new formula and the formulae recently given by other researchers to show the preference of new M5' approach.

  15. Experimental study on wave dissipation of new plate breakwaters%新型透空板式防波堤消浪效果试验研究

    Institute of Scientific and Technical Information of China (English)

    王晶; 程永舟; 杨小桦; 徐宁; 刘仔锋

    2015-01-01

    A new type of pile foundation double horizontal plate breakwater (model c) is presented to in-crease wave energy dissipation and stability of the double-plate breakwater. Based on the physical model experiments, the relationship between the breakwater transmission coefficient and reflection coefficient with relative plate width was obtained and compared with other two kinds of breakwaters (models a and b). It discussed the transmission coefficient and reflection coefficient of new breakwater change with relative wa-ter depth, relative wave steepness, relative submerged depth, and the wave energy dissipation of new break-water was also analyzed. The results show that the new breakwater has good effect on wave absorption for the long period wave in the experimental parameters and the wave energy dissipation is better when the new breakwater elevation as the same with the water level than other elevations.%为增大双层板式防波堤的波能耗散和防波堤结构的稳定,提出了的一种新型桩基双层板式防波堤,通过物理模型试验,对比分析了该防波堤结构(模型 c)与另两种结构型式的防波堤(模型 a、b)在不同的波浪参数下透射系数、反射系数的变化关系,探讨了新型桩基双层板式防波堤(模型 c)透射系数、反射系数随相对波高、相对水深及相对淹没深度的变化关系,分析了其波能损耗情况。结果表明,在试验范围内,对于长周期波,模型 c 比其他两种型式的防波堤消波效果好;当水深与模型顶平齐时新结构(模型 c)对波能的消耗大于淹没和出水两种情况,说明防波堤高程与水位平齐时其消波效果较好。

  16. Reflection of regular and irregular waves from a partially perforated caisson breakwater with a rock-filled core

    Institute of Scientific and Technical Information of China (English)

    LIU Yong; LI Yucheng; TENG Bin; MA Baolian

    2007-01-01

    The reflection of regular and irregular waves from a partially perforated caisson breakwater with a rock-filled core is examined. The present mathematical model is developed by means of the matched eigenfunction method. Numerical results of the present model are compared with the experimental data of different researchers. Numerical examples are given to examine the effect of rock fill on the reflection coefficient. The differences between regular and irregular waves are also investigated by means of theoretical and experimental results. It is found that the minimum reflection coefficient of irregular waves is larger than that of corresponding regular waves, but the contrary is the case for the maximum reflection coefficient.

  17. Reliability Evaluation of Monolithic Vertical Wall Breakwaters Considering Impulsive Wave Breaking Forces and Failure Modes of the Foundation

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Sørensen, Jørgen S.; Christiani, E.

    1994-01-01

    Impulsive wave breaking forces on a vertical caisson breakwater has been included by Takahashi et al, (1994) in Goda's wave pressure formula (Goda et al. 1972 and Goda 1974). Based on these formulae a deterministic design method following the Japanese recommendations has been used for the design...... of a caisson structure. A reliability evaluation of the same structure is then performed using a level II FORM analysis. In this only the failure modes sliding and overturning are taken into account. The various modes of the foundation slip failures are presented. The method of probabilistic foundation...

  18. Modelling of massive particulates for breakwater engineering using coupled FEMDEM and CFD

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The seaward slope of many breakwaters consists of thousands of interlocking units of rock or concrete comprising a massive granular system of large elements each weighing tens of tonnes.The dumped quarry materials in the core are protected by progressively coarser particulates.The outer armour layer of freely placed units is intended to both dissipate wave energy and remain structurally stable as strong flows are drawn in and out of the particulate core.Design guidance on the mass and shape of these units is based on empirical equations derived from sealed physical model tests.The main failure mode for armour layers exposed to severe storms is hydraulic instability where the armour units of concrete or rock are subjected to uplift and drag forces which can in turn lead to rocking,displacement and collisions sufficient to cause breakage of units.Recently invented armour unit designs making up such granular layered system owe much of their success to the desirable emergent properties of interlock and porosity and how these combine with individual unit structural strength and inertial mass. Fundamental understanding of the forces governing such wave-structure interaction remains poor.We use discrete element and combined finite-discrete element methods to model the granular solid skeleton of randomly packed units coupled to a CFD code which resolves the wave dynamics through an interface tracking technique.The CFD code exploits several methods including a compressive advection scheme, node movement, and general mesh optimization.We provide the engineering context and report progress towards the numerical modelling of instability in these massive granular systems.

  19. Functional and environmental design of detached, low crest level breakwaters; Diseno funcional y ambiental de diques exentos de baja cota de coronacion

    Energy Technology Data Exchange (ETDEWEB)

    Bricio Garberi, L.; Negro Valdecantos, V.; Diez Gonzalez, J. J.; Lopez Gutierrez, J. S.

    2010-07-01

    The research work as presented in this article covers the design of detached breakwaters since they constitute a type of coastal defense work with which to combat many of the erosion problems found on beaches in a stable, sustainable fashion. The main aim of this work is to formulate a functional and environmental (non structural) method of design enabling the fundamental characteristics of a detached breakwater to be defined as a function of the effect it is wished to induce on the coast whilst meeting social demands and preserving or improving the quality of the littoral environment. The general applicability of the method is also sought by means of considering relations between variables od different natures (climatic, geomorphologic and geometric) influencing the changes experienced on the coast after the detached breakwater has been built. The study of the relations between the different variables is carried out on the data from a abase of nineteen actual, existing detached breakwaters on the Spanish Mediterranean coastline and follows a methodology based on the implementation of non-dimensional monomials and on a search for relations of dependency between them. Finally, a discussion on the results obtained lead to a proposal for a design method that uses some of the graphic relations found between the variables studied with which the aforesaid main objective is achieved. (Author) 9 refs.

  20. Subtidal eelgrass/macroalgae surveys for the proposed breakwaters at the US Coast Guard Station at Ediz Hook, Washington, March 1993

    Energy Technology Data Exchange (ETDEWEB)

    Shreffler, D.K. [Battelle/Marine Sciences Lab., Sequim, WA (US)

    1993-05-01

    In 1993, the US Coast Guard proposed to construct two breakwaters and a debris boom to protect its existing pier and moored vessels inside Ediz Hook in Port Angeles Harbor, Washington. To assist the US Army Corps of Engineers -- Seattle District in determining the potential environmental impacts of the proposed breakwaters, Battelle/Marine Sciences Laboratory performed subtidal SCUBA surveys as specified in the Washington Department of Fisheries intermediate eelgrass/macroalgae habitat survey guidelines. The objectives of the subtidal surveys were to (1) quantify the shoot densities of eelgrass; (2) provide percent cover estimates for non-eelgrass macroalgae species; (3) develop a site map indicating the qualitative distribution of eelgrass/macroalgae species, substrate characterization, approximate depth contours, and the approximate location of the proposed project features; and (4) document the time and date of the surveys, turbidity/visibility, presence of invertebrate/vertebrate species, and anecdotal observations pertinent to habitat characterization of the project site. A total of 14 dives along 12 transects (T1--T12) were successfully completed between March 15 and March 17, 1993. Eelgrass was observed on all of the transects except T7 and T8 at the western debris barrier and T12 along the waterward margin of the existing T-pier. The vicinity of the proposed east breakwater had the highest eelgrass shoot densities (up to 89 shoots/m{sup 2}) observed by the divers. Macroalgae and invertebrate species diversity were also highest at the east breakwater site. The low eelgrass densities observed at the west debris barrier site (0 to 14 shoots/m{sup 2}) can be attributed mostly to the lack of suitable substrate. The existing layer of wood debris armoring the bottom at the west project site currently limits, and in the areas of heaviest deposition probably precludes, the growth of eelgrass. As was expected, no eelgrass was observed at the south breakwater site.

  1. Seasonal dynamics of fish assemblages on breakwaters and natural rocky reefs in a temperate estuary: consistent assemblage differences driven by sub-adults.

    Science.gov (United States)

    Fowler, Ashley M; Booth, David J

    2013-01-01

    Development of infrastructure around cities is rapidly increasing the amount of artificial substrate (termed artificial reef, 'AR') in coastal marine habitats. However, effects of ARs on marine communities remain unknown, because it is unclear whether ARs can maintain similar communities to natural reefs. We investigated whether well-established (> 30 years old) breakwaters could consistently approximate fish assemblages on interspersed rocky reefs in a temperate estuary over 6 consecutive seasons using regular visual surveys between June 2009 (winter) and November 2010 (spring). We examined whether assemblage differences between reef types were driven by differences in juvenile recruitment, or were related to differences in older life-stages. Assemblages on both reef types were dominated by juveniles (61% of individuals) and sub-adults (34% of individuals). Seasonal fluctuations in assemblage parameters (species richness, diversity, sub-adult abundance) were similar between reef types, and levels of species diversity and assemblage composition were generally comparable. However, abundance and species richness were consistently higher (1.9-7.6 and 1.3-2.6 times, respectively) on breakwaters. These assemblage differences could not be explained by differences in juvenile recruitment, with seasonal patterns of recruitment and juvenile species found to be similar between reef types. In contrast, abundances of sub-adults were consistently higher (1.1-12 times) at breakwaters, and assemblage differences appeared to be driven by this life-stage. Our results indicate that breakwaters in temperate estuaries are capable of supporting abundant and diverse fish assemblages with similar recruitment process to natural reefs. However, breakwaters may not approximate all aspects of natural assemblage structure, with differences maintained by a single-life stage in some cases.

  2. Seasonal dynamics of fish assemblages on breakwaters and natural rocky reefs in a temperate estuary: consistent assemblage differences driven by sub-adults.

    Science.gov (United States)

    Fowler, Ashley M; Booth, David J

    2013-01-01

    Development of infrastructure around cities is rapidly increasing the amount of artificial substrate (termed artificial reef, 'AR') in coastal marine habitats. However, effects of ARs on marine communities remain unknown, because it is unclear whether ARs can maintain similar communities to natural reefs. We investigated whether well-established (> 30 years old) breakwaters could consistently approximate fish assemblages on interspersed rocky reefs in a temperate estuary over 6 consecutive seasons using regular visual surveys between June 2009 (winter) and November 2010 (spring). We examined whether assemblage differences between reef types were driven by differences in juvenile recruitment, or were related to differences in older life-stages. Assemblages on both reef types were dominated by juveniles (61% of individuals) and sub-adults (34% of individuals). Seasonal fluctuations in assemblage parameters (species richness, diversity, sub-adult abundance) were similar between reef types, and levels of species diversity and assemblage composition were generally comparable. However, abundance and species richness were consistently higher (1.9-7.6 and 1.3-2.6 times, respectively) on breakwaters. These assemblage differences could not be explained by differences in juvenile recruitment, with seasonal patterns of recruitment and juvenile species found to be similar between reef types. In contrast, abundances of sub-adults were consistently higher (1.1-12 times) at breakwaters, and assemblage differences appeared to be driven by this life-stage. Our results indicate that breakwaters in temperate estuaries are capable of supporting abundant and diverse fish assemblages with similar recruitment process to natural reefs. However, breakwaters may not approximate all aspects of natural assemblage structure, with differences maintained by a single-life stage in some cases. PMID:24086634

  3. Seasonal dynamics of fish assemblages on breakwaters and natural rocky reefs in a temperate estuary: consistent assemblage differences driven by sub-adults.

    Directory of Open Access Journals (Sweden)

    Ashley M Fowler

    Full Text Available Development of infrastructure around cities is rapidly increasing the amount of artificial substrate (termed artificial reef, 'AR' in coastal marine habitats. However, effects of ARs on marine communities remain unknown, because it is unclear whether ARs can maintain similar communities to natural reefs. We investigated whether well-established (> 30 years old breakwaters could consistently approximate fish assemblages on interspersed rocky reefs in a temperate estuary over 6 consecutive seasons using regular visual surveys between June 2009 (winter and November 2010 (spring. We examined whether assemblage differences between reef types were driven by differences in juvenile recruitment, or were related to differences in older life-stages. Assemblages on both reef types were dominated by juveniles (61% of individuals and sub-adults (34% of individuals. Seasonal fluctuations in assemblage parameters (species richness, diversity, sub-adult abundance were similar between reef types, and levels of species diversity and assemblage composition were generally comparable. However, abundance and species richness were consistently higher (1.9-7.6 and 1.3-2.6 times, respectively on breakwaters. These assemblage differences could not be explained by differences in juvenile recruitment, with seasonal patterns of recruitment and juvenile species found to be similar between reef types. In contrast, abundances of sub-adults were consistently higher (1.1-12 times at breakwaters, and assemblage differences appeared to be driven by this life-stage. Our results indicate that breakwaters in temperate estuaries are capable of supporting abundant and diverse fish assemblages with similar recruitment process to natural reefs. However, breakwaters may not approximate all aspects of natural assemblage structure, with differences maintained by a single-life stage in some cases.

  4. 梳状防波堤上波浪反射%Wave reflection from comb-type breakwater

    Institute of Scientific and Technical Information of China (English)

    傅朝方; 朱大同

    2013-01-01

    The reflection coefficients of perforated-pipe breakwater are studied.Based on analysis of the flow resistance and the nonlinear acceleration term,the analytical formulas of reflected wave heights are obtained.In the formulas,all the parameters can be either obtained from textbooks and manuals,or calculated by structural and hydrologic parameters.The theoretical predictions by the present method are compared with test data,and it is found that the results from this theory are agreeable to experimental data in the literatures.%对梳状沉箱防波堤的波浪反射特征进行研究.在对梳状沉箱防波堤非线性消耗波能机理分析基础上,采用阻抗分析方法,导出一组所有参数都是事先知道的、完全封闭的波反射系数公式.

  5. The Experimental Investigation of the Duckweed-type Floating Breakwater%浮漂式防波堤的试验研究

    Institute of Scientific and Technical Information of China (English)

    吴静萍; 王仁康; 郑晓伟; 姜曼松; 石记柱

    2001-01-01

    模仿水生植物“浮漂”的结构形式,设计一种新形式的防波堤.将多块圆形木板柔性连接成一体,平铺于水面,对其进行了一系列的消浪效果的初步试验研究.试验结果表明,该结构具有消浪性能,并且其固定方式采用系泊于水下的消浪效果优于系泊于岸边的.%This paper presents a new-type floating breakwater with the structure of “duckweed”.Some circular wooden blocks were flexibly tied together and flat located on water surface.A series of experimental investigation were carried out.The experimental results show that 1) there are wave attenuation characteristics of the new-type floating breakwater;2) by comparing the two installation styles,the wave attenuation effectiveness anchored on the sea bed is better than that of anchored on the sea shore.

  6. Study of resonant modes of the harbour of Siracusa, Italy, and of the effects of breakwaters in case of a tsunami event.

    Science.gov (United States)

    Pagnoni, Gianluca; Tinti, Stefano

    2016-04-01

    The eastern coast of Sicily has been hit by many historical tsunamis of local and remote origin. This zone and in particular Siracusa, as test site, was selected in the FP7 European project ASTARTE (Assessment, Strategy And Risk Reduction for Tsunamis in Europe - FP7-ENV2013 6.4-3, Grant 603839). According to the project goals, in this work oscillations modes of the Siracusa harbour were analysed with focus on the typical tsunami periods range, and on the protecting effects of breakwaters by using linear and non-linear simulation models. The city of Siracusa is located north of the homonymous gulf and has two harbours, called "Piccolo" (small) and "Grande" (grand) that are connected through a narrow channel. The harbour "Piccolo" is the object of this work. It is located at the end of a bay facing east and bordered on the south by the peninsula of Ortigia and on the north by the mainland. The basin has an area of approximately 100,000 m2 and is very shallow with an average depth of 2.5 m. It is protected by two breakwaters reducing its mouth to only 40 m width. This study was carried out using the numerical code UBO-TSUFD that solves linear and non-linear shallow-water equations on a high-resolution 2m x 2m regular grid. Resonant modes were searched by sinusoidal forcing on the open boundary with periods in a range from about 60 s to 1600 s covering the typical tsunami spectrum. The work was divided into three phases. First we studied the natural resonance frequencies, and in particular the Helmholtz resonance mode by using a linear fixed-geometry model and assuming that the connecting channel between the two Siracusa ports is closed. Second, we repeated the analysis by using a non-linear simulation model accounting for flooding and for an open connection channel. Eventually, we forced the harbour by means of synthetic signals with amplitude, period and duration of the main historical tsunamis attacking Siracusa, namely the AD 365, the 1693 and the 1908 tsunami

  7. On the Uplift Forces of Waves on the Piled Baffle Permeable Breakwater%桩基挡板式透空堤底板波浪的上托力

    Institute of Scientific and Technical Information of China (English)

    茆福文; 陈德春; 董霞

    2013-01-01

    The uplift forces of waves acting on the plate are the important parameters for designing the piled baffle permeable breakwater.Based on the wave model test,the wave steepness and superelevation are analyszd which are the main factors that influence the uplift forces of the impact pressure on the plate.Through the dimensional analysis and linear regression method,the empirical formula of calculating the uplift forces of the impact pressure on the plate of piled baffle permeable breakwater is derived when 1.67 < d/H < 3.2,0.03 < H/L < 0.1and-0.16 < △h/H < 0.48.Finnaly,compared with the former results,the experimental data show that the expirical formula is consistent with the experiment.%波浪对底板的上托力是桩基挡板式透空堤设计的重要参数.通过波浪模型试验,分析波陡、超高等因素对其底板波浪上托力冲击压强的影响,采用因次分析和线性回归方法,得到1.67<∥H< 3.23,0.03 <H/L <0.1,-0.16<△h/H<0.48波浪条件下,桩基挡板式透空堤底板波浪上托力冲击压强的计算公式,并与以往公式进行比较.试验资料表明,该公式与试验值有较好的一致性.

  8. Benthic Community zonation in a breakwater on the north coast of the state of Rio de Janeiro, Brazil

    Directory of Open Access Journals (Sweden)

    Bruno Pereira Masi

    2009-06-01

    Full Text Available The present study presents the vertical zonation pattern of the intertidal benthic organisms on granitic boulders in the Farol de São Tomé beach (22º02'S, 41º03'W, Rio de Janeiro State. Four sampling profiles using 20 x 20 cm quadrats through a photo quadrat technique revealed four horizontal bands: (1 Littoral Fringe characterized by empty space and Littorina; (2 Upper eulittoral mainly occupied by Chthamalus and bare rock; (3 Lower eulittoral characterized by Chthamalus, Phragmatopoma, Ulva and Centroceras; and (4 Sublittoral Fringe characterized by Ulva, Phragmatopoma and Hypnea. The high variability in the relative abundance of the dominant species among the profiles may be attributed to the high topographic irregularity, reflecting in different wave action intensity at the same height, and consequently favoring the establishment of different species. The frequent substrate alternation from granitic rock to Phragmatopoma sandy reefs might contribute to the small-scale spatial variability. The implantation of a breakwater on an area without natural rocky shores allowed the study of intertidal benthic communty zonation, and provide a baseline for the experimental studies.O presente estudo teve como objetivo apresentar um esquema de zonação vertical de organismos bênticos da região entremarés em blocos graníticos na praia do Farol de São Tomé (22º02'S, 41º03'W na costa norte do estado do Rio de Janeiro. Quadrados de 20 x 20 cm foram sobrepostos em quatro perfis e utilizado o método por foto quadrat com 100 pontos de interseção. A análise de agrupamento e a porcentagem de cobertura de organismos bênticos indicadores sugeriram um padrão na distribuição vertical da região entremarés com quatro faixas: Franja do Supralittoral caracterizado por espaço vazio e Littorina ziczac; Médiolitoral Superior ocupado por Chthamalus spp e espaço vazio; médiolitoral inferior caracterizado por Chthamalus spp, Phragmatopoma lapidosa

  9. Feature articles, thermal power and atomic power. Study on antiseismic property of breakwater bulkhead (model experiment of caisson dike and its numerical simulator). Karyoku, genshiryoku. Bohagogan no teishinsei ni kansuru kenkyu (keson tei no mokei jikken to sono suchi simulation)

    Energy Technology Data Exchange (ETDEWEB)

    Tochigi, H. (Central Research Inst. of Electric Power Industry, Tokyo (Japan))

    1994-05-31

    Recently the social demand is increasing for utilizing the offshore marine space for building an artificial island for air port or power plant. The improvement in reliability of safety of breakwater bulkhead is thus required. In order to rationalize and sensitize the evaluation method of antiseismic stability, the investigation in which the seismic behaviors such as sliding and settling are taken into consideration is required in addition to the conventional investigation based on the seismic intensity method. In this case, if the breakwater bulkhead constructed as the outer shell of the island can keep the stability of the reclaimed ground against the waves even after being deformed to some extent by sliding and settling, the stability of the backward facilities can be kept. In this study, a large scale experiment was conducted for understanding the seismic behavior of the breakwater bulkhead. A numerical simulation was also made for performing various dynamic test on the strength, deformation characteristic, and settlement property of the large size aggregate and for investigating the evaluation of seismic behavior. 7 refs., 16 figs., 1 tab.

  10. The extreme wave interaction with the constructions of the breakwaters including the damping chamber that was filled up with the stones and concrete units

    Science.gov (United States)

    Maximov, Vasily; Nudner, Igor; Revyakin, Alexei

    2010-05-01

    The eight types of the breakwaters constructions including the damping chamber were experimentally studied. The damping chamber has the infilling with the stones, with the concrete units, or with the combinations of the stones and units. The back wall of the damping chamber was impermeable. The construction varies by the volume and by the type of the infilling. The experiments to specify the pressure at the internal walls of the damping chamber, the reflected wave height, and the wave height at the front wall were performed at the hydro flume. This flume has the following dimensions: 43 m length, 0.7 m width, and 1.2 m height. The periodic waves were produced by the shield-type wavemaker. We vary in this research the periods of the waves over the range 0.8 s to 1.64 s, and the wave height over the range 10 cm to 24 cm. The analysis revealed the most improved structure possessing the good wave-protective features.

  11. Numerical Simulation Study on Wave Dissipating Performances of Air Bubbles Breakwater with Single & Double Air Discharge Pipes%单排与双排气幕防波堤消波性能数值模拟

    Institute of Scientific and Technical Information of China (English)

    张成兴; 王永学; 马加

    2011-01-01

    将气液两相流看成是变密度单流体,以连续方程、雷诺平均方程和k-ε模型为控制方程,采用VOF方法追踪两相流界面,通过UDF在连续方程中添加附加质量源项的方法,建立了气幕防波堤数学模型.通过数值计算得到的波浪透射系数同试验数据吻合较好.在此基础上讨论了不同原型入射波浪要素、不同气幕间距以及不同供气量等对单排与双排气幕防波堤消波性能的影响,进而通过分析得出相应的结论,为气幕防波堤的设计提供有意义的依据.%Assuming the two-phase fluid of water and air as a variable density fluid, a numerical model of air bubble breakwater is developed with the continuity equation, Reynolds average equation and k -e model taken as the governing equations, the VOF method for tracing the interface of the two-phase flows, and the additional source term of the air bubble model added to the continuity equation by the Macro of UDF. The transmission coefficients obtained at the different air amounts and the wave periods agree well with the experimental data. The effects of single & double air discharging pipes on the wave dissipating performance of the air bubble breakwater are analyzed with different incident wave characteristics, different distances between two air discharged pipes, the incident wave height and air amounts, then some conclusions are obtained, which are meaningful to study the wave dissipating performances of air bubble breakwaters.

  12. Centrifuge Modeling on Displacement Characteristics of Bucket Foundation Breakwater Under Horizontal Static Load%水平静荷载作用下箱筒型基础防波堤位移特性的离心模拟

    Institute of Scientific and Technical Information of China (English)

    蒋敏敏; 韩尚宇; 蔡正银; 肖昭然

    2012-01-01

    Displacement characteristics of bucket foundation breakwater under horizontal static load are studied through centrifuge model test. Test results show that: breakwater tilts to harbor side, sea side and harbor side will move upward and downward respectively. Tilt angle, harbor side vertical and horizontal displacements decrease with foundation soil strength, while sea side vertical displacement increases, with the larger soil strength. When load ratio is larger than yield load ratio,displacement velocity increases significantly. The yield load ratio increases with the larger foundation soil strength.%通过离心试验对箱筒型基础防波堤在水平静荷载下的位移特性进行了研究.研究表明:防波堤发生向港侧转动,海侧和港侧分别发生向上和向下位移,整个防波堤发生向港侧水平位移.地基土体强度越大,转角、港侧竖向位移量和水平位移量越小,而海侧竖向位移量越大.荷载比大于屈服荷载比后,位移速率显著增大,地基土体强度越高,屈服荷载比越大.

  13. Numerical Simulation, Comparison and Study of Feasibility Proposal of Bata Port Breakwater%巴塔港防波堤设计方案可行性数值模拟对比研究

    Institute of Scientific and Technical Information of China (English)

    蒋勇; 李会兴; 张杰峰

    2015-01-01

    The improved equation Boussinesq has been used as the theoretical control equation, which adopts the numerical model MIKE21-BW to carry out the numerical simulation, comparison and study of four feasibility proposals for extending the breakwater of Bata Port, Equatorial Guinea. In addition, the optimum design of the breakwater has been made through calculating the berthing wave heights at different survey points under the design high water level or wave force in W direction based on the above four proposals.%本文以改进的 Boussinesq 方程为理论控制方程,采用 MIKE21-BW 数值模型对赤道几内亚巴塔港防波堤延长的四种设计方案进行可行性数值模拟对比研究。通过计算4种方案在设计高水位、W 向波浪作用下各测点的泊稳波高,为防波堤结构进行优化设计。

  14. 离心模型试验中深水防波堤上波浪循环荷载的模拟研究%CENTRIFUGE MODELING STUDY OF CYCLIC WAVE LOAD ON BREAKWATER IN DEEP WATER

    Institute of Scientific and Technical Information of China (English)

    蒋敏敏; 蔡正银; 徐光明; 王志选; 肖昭然

    2013-01-01

      研制离心模型试验中新型的非接触式循环荷载加载系统,用于模拟深水防波堤上的波浪荷载,解决了波浪荷载模拟研究中的消能困难、产生附加约束和附加质量以及难以模拟波谷反向荷载等问题,通过计算机控制加载,能够达到模拟风暴荷载的要求。开发动力离心试验的新测控系统,包含高速数据采集、低通数字滤波去除噪声和干扰、改进比例积分微分(PID)加载控制、控制信号生成等功能模块,优化动力离心试验中加载控制和数据采集的功能。通过在离心模型试验中对箱筒型基础防波堤施加非接触式波浪荷载的作用,表明该加载设备可精确、稳定地施加不同的波浪荷载,并可任意调节波浪荷载幅值。得出波浪荷载作用下箱筒形基础防波堤的动位移特征:动倾角的累积值和幅值均有一定的增长,水平位移量以幅值增大为主,而竖向位移量以累积值增大为主;箱筒形基础防波堤主要表现为振动–摇摆耦合运动模式。%  A new non-contact cyclic wave load generation system for centrifuge model test is developed. Through computer controlled load device,the system can simulate storm wave load on breakwater in deep water. The system solves the problems accounted in previous study such as difficulty in energy dissipation,generating additional constraint and mass,and applying of reversal load that is hard to be carried out. Then a new measuring and controlling system is developed for dynamic centrifuge model test,which contains four functional modules:high speed data acquisition,low pass digital filter for signal noise and interference removal,modified proportion integration differentiation(PID) load control and signal generation control. The system also optimizes load control and data acquisition functions in dynamic centrifuge test. The feasibility of non-contact wave load generation system is verified by

  15. Foundation Design of Caisson Breakwaters

    DEFF Research Database (Denmark)

    Groot, M.B. De; Andersen, K.H.; Burcharth, H. F.;

    1996-01-01

    This document has been prepared as a part of the dissemination of results of the MCS-Project (Contract No. MAS2-CT92-0047) which was led by the University of Hannover (Coordinator: H. Oumeraci) within the 2nd Research Programme of the European Union (EU) on Marine and Science Technology. The supp...

  16. Reliability analysis of breakwaters based on the cumulative sampling response surface method%基于样本累积响应面法的防波堤可靠度分析

    Institute of Scientific and Technical Information of China (English)

    刘君; 魏开涛; 易平

    2015-01-01

    reliability of the breakwater for a nuclear power plant was analyzed by the improved method. The results showed that the breakwater has certain failure probability under earthquake excitation. However, such failure proba-bility will be very large if there is a silted floor on the bottom of breakwater, which is rather dangerous to normal op-eration of the nuclear power project and should be provided with more attention.

  17. Pore Pressure Measurements inside Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Helgason, Einar; Burcharth, H. F.; Grüne, Joachim

    Large scale model tests have been performed in the LARGE WAVE CHANNEL (GWK) of the Coastal Research Centre (FZK).......Large scale model tests have been performed in the LARGE WAVE CHANNEL (GWK) of the Coastal Research Centre (FZK)....

  18. WAVE INTERACTION WITH PERFORATED CAISSON BREAKWATERS

    Institute of Scientific and Technical Information of China (English)

    Chen Xue-feng

    2003-01-01

    The reflection coefficient of perforated caissons and the total horizontal forces acting on them were experimentally and numerically analyzed and discussed when wave propagates normally. To consider the viscosity effect of fluid and nonlinear action of waves on structures, the VOF (Volume Of Fluid) method combined with the k-ε turbulence model was used to simulate the interaction between waves and structures. Governing equations were solved with the finite difference method. Through 2D experimental study in the wave flume, the empirical relationship between the reflection coefficient of perforated caissons and the main affecting factors were obtained from the experimental data using the least square method. Also the correlation between the ratio of the total horizontal force acting on perforated caisson and the force acting on solid caisson and the main affecting factors were regressed from the experimental data.

  19. Laboratory Experiments on Low-crested Breakwaters

    DEFF Research Database (Denmark)

    Kramer, Morten Mejlhede; Zanuttigh, B.; van der Meer, J. W.;

    2004-01-01

    The ducument describe 3D tests at scale 1:20 performed in the Laboratory at Department of Civil Engineering, Aalborg University.The wave obliquity was one of the main parameters, which were studied in the wave basin experiments. The experiments provide unique information about the influences...

  20. Laboratory Experiments on Low-crested Breakwaters

    DEFF Research Database (Denmark)

    Kramer, Morten; Zanuttigh, B.; van der Meer, J.W.;

    2005-01-01

    New unique laboratory experiments on low-crested structures (LCSs) have been performed within the DELOS project. The experiments were carried out in three European laboratories aiming at extending and completing existing available information with respect to a wide range of engineering design...... in a wave channel at small scale, and scale effects regarding wave transmission and reflection were studied in a wave channel at a large scale facility. The paper describes the experiments and associated databank with respect to objectives, test program, set-ups and measurements. Results, guidelines...

  1. Toe Structure Stability of Sloping Breakwater

    Institute of Scientific and Technical Information of China (English)

    吴中; 嵇才苏

    2003-01-01

    Based on physical model tests, the rubble mound toe structure stability under the action of both regular and irregular waves is studied. Test results show that wave height and water depth at the toe structure are the most important factors affecting the stability of toe berm stone, and that irregular waves cause greater damage to the toe structure than regular waves. Analyses prove that the Gerding formula agrees better with our test results than the Meer formula. Tests on two different types of main armors also indicate that the shape and composition of the main armor have effect on the stability of the toe structure.

  2. Pore Pressure Measurements Inside Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Helgason, Einar; Burcharth, H. F.; Grüne, Joachim

    2004-01-01

    The present paper presents pore pressure measurements from large scale model tests performed at the Large Wave Channel, Hannover, Germany and small scale model test performed at the Hydraulic & Coastal Engineering Laboratory, Aalborg University, Denmark. Information on pore pressure attenuation a...

  3. The Permeability of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Williams, A.F.; Burcharth, H. F.; Adel, H. den

    1992-01-01

    The results of an extensive series of permeability experiments originally analysed by Shih (1990) are reinterpreted in the light of new experiments. It is proposed that the Forchheimer equation might not fully describe flow at the high Reynolds numbers found in the interior of rubble material. A...... new series of tests designed to test for deviations from the Forchheimer equation and investigate the effects of material shape are described. While no evidence can be found to indicate a deviation from the Forchheimer equation a dependency of permeability and the surface roughness the material is...

  4. Stability analysis of rubblemound breakwater using ANN

    Digital Repository Service at National Institute of Oceanography (India)

    Mandal, S.; Rao, S.; Manjunath, Y.R.; Kim, D.H.

    Engineering, Kunsan Jeonbuk South Korea eastlite@kunsan.ac.kr ABSTRACT The stability analysis of coastal structure is very important because it involves many design parameters to be considered for the safe and economical design of structure...

  5. Structural Stability Of Detached Low Crested Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Kramer, Morten; Lamberti, Alberto;

    2006-01-01

    determining armour stone size in shallow water conditions is given together with a rule of thumb for the required stone size in depth-limited design waves. Rock toe stability is discussed on the basis of prototype experience, hard bottom 2-D tests in depth-limited waves and an existing hydraulic stability...

  6. State of the Art in the Conceptual Design of Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, H. F.

    2000-01-01

    Design and construction of coastal structures have always been a challenge as engineers are working in still more exposed locations, and the former acceptance of some failures caused by the inpredictable sea is no more valid . Today it is generally expected that the coastal engineer can cope...... with the vagaries of nature and produce structures which will survive and function for several generations. The design tools available to us are better than ever and we can, in a rational way, deal with the uncertainties inherent in sea states and structural responses. Provided no failure mode is overlooked we can...... in fact design on the basis of target probability of specific damage within structure lifetime, identified by economic optimization....

  7. The effect of foreshore slope on breakwater stability

    NARCIS (Netherlands)

    Verhagen, H.J.

    2005-01-01

    In case of coasts with steep foreshores coastal structures suffer more from damage than normally could be expected from given boundary conditions at deep water. For that reason in many guidelines it is recommended to apply a heavier class of rock in those cases; manufacturers of single layer units (

  8. Stability of Reshaping Breakwaters with Special Reference to Stone Durability

    DEFF Research Database (Denmark)

    Frigaard, Peter; Hald, Tue; Burcharth, H. F.;

    1996-01-01

    inherently cause some breakage and abrasion of the individual stones and thereby also reduced stability. In order to avoid excessive abrasion a high stone quality is demanded or larger stones must be applied when constructed. To allow the designer to account for abrasion and armour stone breakage due...... movements. Also tensile stresses occur, as a result of stone against stone impact are discussed in order to make a more close connection between wave climate, stone movements and abrasion/breakage. Finally, a comparison to selected prototype structures is made to compare the armour stone movement model...

  9. Scaling of Core Material in Rubble Mound Breakwater Model Tests

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Liu, Z.; Troch, P.

    1999-01-01

    that the diameter of the core material in models is chosen in such a way that the Froude scale law holds for a characteristic pore velocity. The characteristic pore velocity is chosen as the average velocity of a most critical area in the core with respect to porous flow. Finally the method is demonstrated......The permeability of the core material influences armour stability, wave run-up and wave overtopping. The main problem related to the scaling of core materials in models is that the hydraulic gradient and the pore velocity are varying in space and time. This makes it impossible to arrive at a fully...... correct scaling. The paper presents an empirical formula for the estimation of the wave induced pressure gradient in the core, based on measurements in models and a prototype. The formula, together with the Forchheimer equation can be used for the estimation of pore velocities in cores. The paper proposes...

  10. Wave Run-up on the Zeebrugge Rubble Mound Breakwater

    DEFF Research Database (Denmark)

    De Rouck, Julien; Van de Walle, Björn; Troch, Peter;

    2007-01-01

    A clear difference between full-scale wave run-up measurements and small-scale model test results had been noticed during a MAST II project. This finding initiated a thorough study of wave run-up through the European MAST III OPTICREST project. Full-scale measurement have been carried out......-up has been measured by a digital run-up gauge. This gauge has proven to measure wave run-up more accurately than the traditional wire gauge. Wave spectra measured in Zeebrugge have been reproduced in the laboratories. Results of small-scale model tests and full-scale measurements results have been...... compared. This comparison confirmed the MAST II outcome: wave run-up is underestimated by small-scale model tests. The difference between full-scale measurement results and small-scale model test results is the result of model effects. The porosity of the armor layer has a significant influence on wave run...

  11. Flow in Porous Media with Special Reference to Breakwater Structures

    DEFF Research Database (Denmark)

    Andersen, O. Holst

    A literature study concerning porous flow is carried out. For the stationary case, the hydraulic radius theory, for which some justification can be given based on Navier-Stokes equations, appears to be adequate. Three different porous flow regimes are identified and the associated flow resistance...... coefficients are found from the literature. For the non-stationary flow case, existing expressions are discussed, and with the aim of decribing the inertia term a new analogy based on cylinders/spheres is presented. The predicted variation of the virtual mass coefficient with the porosity compares to a series...

  12. Hybrid morphological modelling of shoreline response to a detached breakwater

    DEFF Research Database (Denmark)

    Kristensen, Sten Esbjørn; Drønen, Nils; Deigaard, Rolf;

    2013-01-01

    the evolving cross-shore profile is described by a limited number of parameters. The hybrid morphological model is a strong tool for medium and long term modelling because it is cost effective while containing important features of the sediment transport description.Two versions of the model are developed...

  13. On Establishing Big Data Wave Breakwaters with Analytics (Invited)

    Science.gov (United States)

    Riedel, M.

    2013-12-01

    The Research Data Alliance Big Data Analytics (RDA-BDA) Interest Group seeks to develop community based recommendations on feasible data analytics approaches to address scientific community needs of utilizing large quantities of data. RDA-BDA seeks to analyze different scientific domain applications and their potential use of various big data analytics techniques. A systematic classification of feasible combinations of analysis algorithms, analytical tools, data and resource characteristics and scientific queries will be covered in these recommendations. These combinations are complex since a wide variety of different data analysis algorithms exist (e.g. specific algorithms using GPUs of analyzing brain images) that need to work together with multiple analytical tools reaching from simple (iterative) map-reduce methods (e.g. with Apache Hadoop or Twister) to sophisticated higher level frameworks that leverage machine learning algorithms (e.g. Apache Mahout). These computational analysis techniques are often augmented with visual analytics techniques (e.g. computational steering on large-scale high performance computing platforms) to put the human judgement into the analysis loop or new approaches with databases that are designed to support new forms of unstructured or semi-structured data as opposed to the rather tradtional structural databases (e.g. relational databases). More recently, data analysis and underpinned analytics frameworks also have to consider energy footprints of underlying resources. To sum up, the aim of this talk is to provide pieces of information to understand big data analytics in the context of science and engineering using the aforementioned classification as the lighthouse and as the frame of reference for a systematic approach. This talk will provide insights about big data analytics methods in context of science within varios communities and offers different views of how approaches of correlation and causality offer complementary methods to advance in science and engineering today. The RDA Big Data Analytics Group seeks to understand what approaches are not only technically feasible, but also scientifically feasible. The lighthouse Goal of the RDA Big Data Analytics Group is a classification of clever combinations of various Technologies and scientific applications in order to provide clear recommendations to the scientific community what approaches are technicalla and scientifically feasible.

  14. Variação do número de estômatos e micropêlos em Paspalum vaginatum Sw: em relação às condições abióticas numa marisma do estuário da Lagoa dos Patos, RS-Brasil Variation in the number of stomata and microhairs of Paspalum vaginatum Sw: en relation to abiotic conditions in a breakwater in the Lagoa dos Patos estuary, RS-Brazil

    Directory of Open Access Journals (Sweden)

    Eleci de Oliveria Bastos

    1992-12-01

    Full Text Available Paspalum vaginatum Sw., gramínea perene, estolonífera, com folhas anfistomáticas e pequenas é característica de pântanos salgados, crescendo em condições estressantes na marisma da lagoa dos Patos, molhe oeste da Barra do Rio Grande, RS. Foram feitas contagens mensais de estômatos e micropêlos nas superfícies adaxial e abaxial das lâminas e relacionadas às características abióticas do ambiente. O número de micropêlos da superfície foliar abaxial variou significativamente e diretamente com a temperatura da água intersticial junto às rizosferas. Estes, porém, não mantiveram correlação com a salinidade intersticial. Os resultados sugerem que a espécie seja uma halófita facultativa. O número de estômatos da superfície abaxial manteve um relacionamento inverso com a pluviosidade. Paspalum vaginatum, apresenta-se como uma espécie com características xeromórficas.Paspalum vaginatum Sw., a perennial, stoloniferous grass with small leaves presenting stomata on both epidermises is characteristic of salt marshes, growing under stressful conditions near the west breakwater of the Rio Grande outlet, Lagoa dos Patos, Rio Grande do Sul, Brazil. Monthly counts of stomata and microhairs on the adaxial and abaxial surfaces were related to the abiotic characteristics of the enviroment. The number of microhairs of the abaxial leaf surface varied significantly and directly with interstitial water temperature close to the rhyzosphere. However, these counts did not correlate with the interstitial salinity. The results suggest that the species is a facultative halophyte. Stomata counts of the abaxial surface showed an inverse relation to precipitation. Paspalum vaginatum appears to be a species with xeromorphic characteristics.

  15. Portable floating breakwater for controlling bar formation and sediment transport near tidal inlets

    Digital Repository Service at National Institute of Oceanography (India)

    Vethamony, P.; Krishnakumar, V.; Swamy, G.N.

    stream_size 4 stream_content_type text/plain stream_name Inst_Eng_India_J_76_185.pdf.txt stream_source_info Inst_Eng_India_J_76_185.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset=ISO-8859-1 ...

  16. Single Wave Overtopping Volumes and their Travel Distance for Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Burcharth, Hans F.; Gironella, F. X.

    2009-01-01

    In the present paper small and large scale overtopping data for rubble mound structures have been analysed with respect to single wave overtopping volumes and their travel distance. The analysis has led to formulae for estimation of maximum single wave overtopping volumes and their travel distance...... similar to the spatial distribution of the total overtopping volume in a sea state....

  17. On The Use Of High-Density Rock In Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Helgason, Einar; Burcharth, H. F.

    2005-01-01

    Natural rock with high density is widely used in the Scandinavian countries. However, the use of natural rock with density higher than 2:9t=m3 is ordinarily associated with some kind of problem solving, e.g. where normal density stones have to be replaced with heavier stones without increasing th...... on stability from the increased density is overestimated by conventional armour stability formulae in case of steep slopes. The infuence of the density depends on the slope angle and the type of armour units....... the construction volume or layer thickness. Most common design formulae do not give a clear conclusion on the in°uence of the rock density on the stability. The present paper presents results of small and large scale model tests in which is used rock with different densities. It is shown that the positive effect...

  18. Direct Numerical Simulation of Interaction Between Wave and Porous Breakwater Based on N-S Equation

    Institute of Scientific and Technical Information of China (English)

    WANG Deng-ting

    2012-01-01

    In this paper,a numerical model is established.A modified N-S equation is used as a control equation for the wave field and porous flow area.The control equations are discreted and solved by the finite difference method.The free surface is tracked by the VOF method.The pressure field and velocity field of the whole flow area are solved by the reiterative iteration method.Finally,compared with the physical model test results of wave flume,the numerical model established in the present study is validated.

  19. Power Production from Integration of SSG in a Breakwater at Liseleje

    DEFF Research Database (Denmark)

    Borgarino, Bruno; Kofoed, Jens Peter

    This report presents the steps carried out in order to propose a SSG setup at Liseleje location. The goal is to give an estimation of the available power and  flow in the harbour. These data will assist the projects managers in their applications for funds and consents. Because the project is at ......]. It is an occasion of testing the enhanced version of the software for simulating the SSG structure and it provides a first experience in working with the modified tool. The study uses the previously calculated sea states at Liseleje [1], given in Section A....

  20. Study on Scattering Wave Force of Horizontal and Vertical Plate Type Breakwaters

    Institute of Scientific and Technical Information of China (English)

    WANG Ke; ZHANG Xi; GAO Xin

    2011-01-01

    The interaction between wave and horizontal and vertical plates is investigated by the boundary element method,and the relations of wave exciting force with plate thickness,submergence and length are obtained.It is found that:1)The efficient wave exciting force exists while plate submergence is less than 0.5 m,and the plate is very thin with order O(0.005 m).2) The maximum heave wave exciting force exists,and it is the main factor for surface and submerged horizontal plate while the roll force can be ignored.3) The maximum sway wave exciting force exists,it is the main factor for surface or submerged vertical plate,and the roll force is about 20 times of horizontal plate.

  1. Large Scale Experiments on the Interaction of a Caisson Breakwater with Breaking Waves

    DEFF Research Database (Denmark)

    Stagonas, Dimitris; Marzeddu, Andrea; Buccino, Mariano;

    2014-01-01

    measurements were complimented with high speed and high definition video records. ln addition, a pressure mapping system employing tactile pressure sensors was deployed in cornbination with force panels, both positioned at still water level. Although at a very early stage, data analysis yields promising...

  2. Damage Accumulation in Vertical Breakwaters due to Combined Impact Loading and Pulsating Wave Loads

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Nielsen, Søren R. K.

    1999-01-01

    elasto-plastic oscillator. The pulsating part of the wave loading is modelled as a filtered white noise process, and the impact load is modelled by a filtered Poisson process. It is shown how a distribution function for the accumulated permanent deformations can be obtained. Finally, an illustrative...

  3. Two-Dimensional Model Test Study of the New Caisson Breakwater at Playa Blanca, Lanzarote

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Garborg, Karsten; Stagsted, Esben Rubech

    This report present the results of 2-D physical model tests (length scale 1:42.5) carried out in a wave flume at Department of Civil Engineering, Aalborg University (AAU) on behalf of SENER Ingenera y Sistemas S.A. Associate Prof. Thomas Lykke Andersen was in charge of the model tests, assisted...

  4. Three-Dimensional Model Test Study of the New Breakwaters at Playa Blanca, Lanzarote

    OpenAIRE

    Andersen, Thomas Lykke; Garborg, Karsten; Stagsted, Esben Rubech

    2012-01-01

    This report present the results of 3-D physical model tests (length scale 1:42.5) carried out in a wave bassin at Department of Civil Engineering, Aalborg University (AAU) on behalf of SENER Ingenera y Sistemas S.A. Associate Prof. Thomas Lykke Andersen was in charge of the model tests, assisted by B.Sc. Karsten Garborg and B.Sc. Esben Rubeck Stagsted. Engineer assistant Niels Drustrup and Leif Mortensen assisted in the laboratory with the construction and instrumentation of the model. The mo...

  5. Scouring of a sand bed in front of a vertical breakwater

    NARCIS (Netherlands)

    De Best, A.; Bijker, E.W.

    1971-01-01

    The scouring profile of a bottom consisting of movable material as this is formed in front of a vertical wall under influence of the standing wave against this wall is discussed. The form of this profile is different for coarse and fine material. In the case of fine material this material is moved i

  6. Scale Effects Related to Small Physical Modelling of Overtopping of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Andersen, Thomas Lykke

    2009-01-01

    in the paper and it is explained why it is impossible quantitatively to identify model and scale effects by comparison of the performance of prototype and small scale models. For such identification are needed special dedicated tests. The paper presents such a test which identify the scale effect in the rubble......By comparison of overtopping discharges recorded in prototype and small scale physical models it was demonstrated in the EU-CLASH project that small scale tests significantly underestimate smaller discharges. Deviations in overtopping are due to model and scale effects. These effects are discussed...... armour on the upper part of the slope. This effect is believed to be the main reason for the found deviations between overtopping in prototype and small scale tests....

  7. Three-Dimensional Model Test Study of Modified Caisson Breakwater at Port of Castellon, Spain

    DEFF Research Database (Denmark)

    Nørgaard, Jørgen Harck; Andersen, Thomas Lykke

    This report present the results of 3-D physical model tests (length scale 1:60) carried out in a wave basin at Department of Civil Engineering, Aalborg University (AAU) on behalf of the client; BP OIL ESPAÑA. The report describe the model testing of the proposed modifications to the existing...

  8. Three-Dimensional Model Test Study on the Existing Caisson Breakwater at Port of Castellon, Spain

    DEFF Research Database (Denmark)

    Nørgaard, Jørgen Harck; Andersen, Thomas Lykke

    This report present the results of 3-D physical model tests (length scale 1:60) carried out in a wave basin at Department of Civil Engineering, Aalborg University (AAU) on behalf of the client; BP OIL ESPAÑA. Associate Prof. Thomas Lykke Andersen and M.Sc. Jørgen Quvang Harck Nørgaard were...

  9. Parameter optimization using GA in SVM to predict damage level of non-reshaped berm breakwater.

    Digital Repository Service at National Institute of Oceanography (India)

    Harish, N.; Lokesha.; Mandal, S.; Rao, S.; Patil, S.G.

    tools, such as Artificial Neural Network (ANN), Support Vector Machine (SVM), Adaptive Neuro Fuzzy Inference System (ANFIS), etc., are successfully used in different fields (Kazperkiewiecz et al 1995, Voga and Belchior 2006, Dong et al 2005). Also... Balas C.E., Koc M.L. and Tur R.(2010) ‘’Artificial neural networks based on principal component analysis, fuzzy systems and fuzzy neural networks for preliminary design of rubble mound breakwaters’’, Applied Ocean Research, 32, 425 – 433. Dong B., Cao C...

  10. Adaptive neuro fuzzy inference system modeling to predict damage level of non-reshaped berm breakwater

    Digital Repository Service at National Institute of Oceanography (India)

    Harish, N.; Mandal, S.; Rao, S.; Lokesha

    coefficient (CC) and scatter index (SI) for test data are 8.072, 2.841, 0.92, and 0.218 respectively. Comparing with the artificial neural network model, ANFIS yields higher CC and lower SI. From the results it can be concluded that ANFIS can be an efficient...

  11. Damage level prediction of non-reshaped berm breakwater using ANN, SVM and ANFIS models

    Digital Repository Service at National Institute of Oceanography (India)

    Mandal, S.; SubbaRao; Harish, N.; Lokesha

    Marine Structures Laboratory, Department of Applied Mechanics and Hydraulics, NITK, Surathkal, India. Soft computing techniques like Artificial Neural Network (ANN), Support Vector Machine (SVM) and Adaptive Neuro Fuzzy Inference system (ANFIS) models...

  12. Three-Dimensional Model Test Study of the New Breakwaters at Playa Blanca, Lanzarote

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Garborg, Karsten; Stagsted, Esben Rubech

    This report present the results of 3-D physical model tests (length scale 1:42.5) carried out in a wave bassin at Department of Civil Engineering, Aalborg University (AAU) on behalf of SENER Ingenera y Sistemas S.A. Associate Prof. Thomas Lykke Andersen was in charge of the model tests, assisted...

  13. Geotechnical Failure of a Concrete Crown Wall on a Rubble Mound Breakwater Considering Sliding Failure and Rupture Failure of Foundation

    DEFF Research Database (Denmark)

    Christiani, E.; Burcharth, H. F.; Sørensen, John Dalsgaard

    1995-01-01

    are calculated for a given design by Bradbury et al. (1988a,b) and compared to acceptable overtopping rates, prior to a determininstic design. The method of foundation stability analysis is presented by the example of a translation slip failure involving kinematically correct slip surfaces and failure zones...

  14. Hybrid genetic algorithm tuned support vector machine regression for wave transmission prediction of horizontally interlaced multilayer moored floating pipe breakwater

    Digital Repository Service at National Institute of Oceanography (India)

    Patil, S.G.; Mandal, S.; Hegde, A.V.; Muruganandam, A.

    ). Apart from ANNs, many authors have used a new approach to solve coastal engineering problems like genetic programming by Gaur and Deo (2008) for real time wave forecasting, Guven et al. (2009) for prediction of circular pile scour. Adaptive neuro...- fuzzy inference system by Sylaios (2009) for wind wave modeling, Model trees by Shahidi and Mahjoobi (2009) for prediction of signifi cant wave height. Support vector machines by Han et al. (2007) for fl ood forecasting, Radhika and Shashi (2009...

  15. Neuro-fuzzy based approach for wave transmission prediction of horizontally interlaced multilayer moored floating pipe breakwater

    Digital Repository Service at National Institute of Oceanography (India)

    Patil, S.G.; Mandal, S.; Hegde, A.V.; Alavandar, S.

    used by the researchers to predict ocean wave parameters like wave height, wave period, impact wave force, etc. ([Deo et al., 2001], [Deo and Jagdale, 2003], [Gunaydin, 2008] and [Londhe and Deo, 2003]). Apart from this, it has provided promising.... The most significant features of neural networks are the extreme flexibility, due to learning ability and the capability of nonlinear function approximations. This fact leads us to expect neural networks to be an excellent tool for solving the motion...

  16. Geometry Optimization of an Overtopping Wave Energy Device Implemented into the New Breakwater of the Hanstholm Port Expansion

    DEFF Research Database (Denmark)

    Margheritini, Lucia; Stratigaki, Vasiliki; Troch, Peter

    2012-01-01

    The study presented here describes the geometry optimization of the Sea wave Slot cone Generator (SSG) overtopping wave energy converter as part of the feasibility study for the implementation of the device in the development plan of Hanstholm harbour in Denmark. The total length of the new plann...

  17. Reliability Evaluation of a Concrete Crown Wall on a Rubble Mound Breakwater considering Sliding Failure, Overturning and Rupture Failure of the Foundation

    DEFF Research Database (Denmark)

    Christiani, E.; Sørensen, Jørgen S.; Burcharth, Hans F.

    1994-01-01

    and rupture failure in the rubble mound are taken into account. The method of probabilistic foundation stability analysis is presented by the example of a translation slip failure involving kinematically correct slip surfaces and failure zones in friction based soil. A conventional static quasi...

  18. Genetic algorithm based support vector machine regression in predicting wave transmission of horizontally interlaced multi-layer moored floating pipe breakwater

    Digital Repository Service at National Institute of Oceanography (India)

    Patil, S.G.; Mandal, S.; Hegde, A.V.

    concluded that the ANFIS model is more flexible 4 than the FIS model, with more options for incorporating the fuzzy nature of the real world system. Sylaios et al., [23] have used Takagi-Sugeno [32] rule based fuzzy inference system for forecasting... coastal engineering problems like genetic programming by Gaur and Deo [35] for real time wave forecasting, Guven et al.,[36] for prediction of circular pile scour. SVMs are the recently developed learning techniques that have gained enormous popularity...

  19. Characteristics of Wave Reflection for Vertical and Slit Caissons with Porous Structures

    OpenAIRE

    Tae-Hwa Jung; Sung-Jae Lee; Yong-Sik Cho

    2012-01-01

    Offshore structures are occasionally located at a relatively deep water region, the outside of breakwater. In this case, these structures may be damaged by the supposition of incident and reflected waves from a vertical breakwater. To prevent the damage, the reflected waves are controlled by installing porous structures at the face of the vertical breakwater. In this study, numerical experiments are carried out to identify the characteristics of wave reflection from the porous structures inst...

  20. Integrated construction technology of gantry mounting and template for breakwater crest wall%防波堤胸墙施工中门架模板一体式的工艺

    Institute of Scientific and Technical Information of China (English)

    罗柳; 唐蔚东; 谭永安; 唐如蜜

    2013-01-01

    In order to guarantee the quality and efficiency of a deepwater breakwater’s 1 510 m long crest wall, according to the difficulties that the wave breast wall is of 6.5 meters high, containing 20%stones, and with narrow passages, etc. we carry out a research on the construction technology of the crest wall, and develop the integrated construction technology of gantry mounting and template innovatively. For the technology, we design the bottom crest wall gantry mounting and the top crest wall gantry mounting in view of the template’s installation, riprap technology, as well as the allocation of resources. By the special technology, we realize the quickest construction at that time under the prerequisite of guaranteeing the casting technology of the crest wall.%为了高质高效地完成某深水防波堤1510 m防浪胸墙施工,根据防浪胸墙高6.5 m、掺石20%、通道狭窄等难点,在对防浪胸墙施工工艺进行了深入的研究后,创新地采用了门架模板一体式施工工艺。针对该工艺,综合考虑模板安拆、抛石工艺、资源配置等情况,设计了底层胸墙门架、顶层胸墙门架。该特殊施工工艺在保证防浪胸墙浇筑质量的前提下,创造了防波堤施工史上的最快速度。

  1. Breakwater Engineering at Marsaxlokk Port of the Republic of Malta%马耳他共和国马尔萨什洛克港防波堤工程

    Institute of Scientific and Technical Information of China (English)

    孙一冰

    2008-01-01

    马耳他共和国马尔萨什洛克港防波堤工程为当年我国水运工程实践规模最大、技术最复杂的工程.最大水深一28m,设计最大波高10m,最大沉箱7000t,最重块体20t.文章由十余万字的工程总结缩编而成,内容以施工为主,主要介绍在极端困难条件下,如何千方百计完成艰巨的施工任务.

  2. Breakwater engineering at Marsaxlokk Port of the Republic of Malta%马耳他共和国马尔萨什洛克港防波堤工程

    Institute of Scientific and Technical Information of China (English)

    孙一冰

    2011-01-01

    马耳他共和国马尔萨什洛克港防波堤工程为当年我国水运工程实践规模最大、技术最复杂的工程.最大水深-28 m,设计最大波高10m,最大沉箱7000t,最重块体20t.文章由十余万字的工程总结缩编而成,内容以施工为主,主要介绍在极端困难条件下,如何千方百计完成艰巨的施工任务.

  3. Material, Structural Design of Armour Units

    DEFF Research Database (Denmark)

    Burcharth, Hans F.

    Stone and concrete are two materials generally used for the construction of rubble mound breakwaters. This paper deals with concrete only.......Stone and concrete are two materials generally used for the construction of rubble mound breakwaters. This paper deals with concrete only....

  4. The Importance of Pressure Sampling Frequency in Models for Determination of Critical Wave Loadings on Monolithic Structures

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Andersen, Thomas Lykke; Meinert, Palle

    2008-01-01

    Wave induced pressures on model scale monolithic structures like caissons and concrete superstructures on rubble mound breakwaters show very peaky variations, even in cases without impacts from slamming waves.......Wave induced pressures on model scale monolithic structures like caissons and concrete superstructures on rubble mound breakwaters show very peaky variations, even in cases without impacts from slamming waves....

  5. Safety of Marine Structures

    DEFF Research Database (Denmark)

    Burcharth, H. F.

    1990-01-01

    of a "future safe" design code for exposed marine structures like breakwaters should be different from the ones usually applied in modern design standards for conventional structures within civil engineering. Moreover, results from ongoing development of a design code for rubble mound breakwaters are presented....

  6. Permeability of Rubble Mound Material

    DEFF Research Database (Denmark)

    Williams, A.F.; Burcharth, H. F.; Adel, H. den;

    The flow of water through the pores of rubble mound breakwaters has two effects upon breakwater performance. The pore pressures generated within the rubble material will effect the stability of the mound. The flow of water in and out of the pores plays a critical part in the dissipation of wave e...

  7. Wave Reflection

    DEFF Research Database (Denmark)

    Helm-Petersen, J.; Frigaard, Peter

    1994-01-01

    This report is Aalborg University's first contribution to the MAS2-CT92 project: Full scale dynamic load monitoring of rubble mound breakwaters.......This report is Aalborg University's first contribution to the MAS2-CT92 project: Full scale dynamic load monitoring of rubble mound breakwaters....

  8. Transformation of statistical and spectral wave periods crossing a smooth low-crested structure

    Directory of Open Access Journals (Sweden)

    Dalibor Carevic

    2012-02-01

    Full Text Available We carried out experimental studies of a smooth submerged breakwater in a wave channel in order to study such a structure impacts on thechanges of statistically and spectrally defined representative wave periods as waves cross it. We discuss the impact of relative submersion, i.e.the relationship between the breakwater crown submersion and the incoming significant wave length Rc / Ls-i, on the representative wave periods.The mean periods, estimated using statistical and spectral methods, were compared in front of and behind the breakwater: the two periods turned out to beidentical. Based on the measurements of the spectral mean wave periods in front of and behind the breakwater, an empirical model is derived for estimating the reduction in mean spectral period for submerged and emerged smooth breakwaters.

  9. Design of north bulkhead of Hitachi-Naka thermal power station and characteristics of the coastal hydraulics; Hitachinaka karyoku hatsudensho kitagogan no sekkei to kaigan suirijo no tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Fukazawa, A.; Sato, Y.; Fujita, Y. [Electric Power Development Co. Ltd., Tokyo (Japan)

    1995-01-05

    For the bulkhead construction of Hitachi-Naka No. 4 Quay where the Hitachi-Naka Thermal Power Station is to be built, Electric Power Development Co., Ltd. is constructing the north bulkhead. The north bulkhead is constructed perpendicularly to the coast line. Since the wave affects the structures as an alongshore wave, the flow condition surrounding the levee body, stability of root protection blocks, and wave pressure affecting caissons are considered to be different from the common case in which the incident wave comes from the front of levee body. This paper describes the design of north bulkhead, in which these phenomena are taken into account. The north bulkhead has been designed as a breakwater combining the rubble-mound inclined breakwater and the caisson type composite breakwater. For the design of north bulkhead, weight of the root protection block was decided considering influence of the slanting wave incidence. Furthermore, results of investigation on the flow condition surrounding the breakwater are described. Are illustrated the periodic change of incident wave, the frequency spectrum and directional spectrum of incident wave, the water level variation surrounding breakwater, wave height distribution surrounding breakwater, and the flow velocity distribution surrounding breakwater. 8 refs., 20 figs., 4 tabs.

  10. Application to Representative Structures. Other Representative Structures: Mutsu-Ogawara, Niigata East and West

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Burcharth, Hans F.

    1999-01-01

    Reliability analyses are performed for three Japanese vertical wall breakwaters in this chapter. Only the geotechnical failure modes described in chapter 3 are investigated. For none of the breakwaters detailed data are available for the wave climate and for the soil conditions. Therefore represe...... representative values for those parameters are used and consequently the results should be considered as the result of a parameter study. The following three breakwaters are considered in sections 2, 3 and 4: Mutsu-Ogawara, Niigata East and Niigata West....

  11. Characteristics of Wave Reflection for Vertical and Slit Caissons with Porous Structures

    Directory of Open Access Journals (Sweden)

    Tae-Hwa Jung

    2012-01-01

    Full Text Available Offshore structures are occasionally located at a relatively deep water region, the outside of breakwater. In this case, these structures may be damaged by the supposition of incident and reflected waves from a vertical breakwater. To prevent the damage, the reflected waves are controlled by installing porous structures at the face of the vertical breakwater. In this study, numerical experiments are carried out to identify the characteristics of wave reflection from the porous structures installing in front of a vertical or slit caisson.

  12. Directional waverider buoy in Indian waters - Experiences of NIO

    Digital Repository Service at National Institute of Oceanography (India)

    AshokKumar, K.; Diwan, S.G.

    Information on directional waves is extremely important in the design of harbour structures, such as breakwaters and jetties and to study the sediment transport pattern. Till recent days our country has been using waverider buoys which give all wave...

  13. Variations in wave direction estimated using first and second order Fourier coefficients

    Digital Repository Service at National Institute of Oceanography (India)

    SanilKumar, V.; Anand, N.M.

    In most design applications such as alignment of the berthing structure and breakwater alignment, it becomes necessary to determine the direction of design wave. There are two different approaches to determine wave direction. One involves the use...

  14. Local scour at roundhead and along the trunk of low crested structures

    DEFF Research Database (Denmark)

    Sumer, B. Mutlu; Fredsøe, Jørgen; Lamberti, Alberto;

    2005-01-01

    not exhibit the pattern experienced in the case of emerged breakwaters where the scour and deposition areas are bcorrelatedQ with the nodal and antinodal points of the standing wave in front of the structure. Furthermore, it was found that scour occurs not only at the offshore side of the breakwater but also....... The breakwater models have a side slope of 1: 1.5. To substantiate scour measurements, velocity measurements also were made. The latter data were used to obtain steady streaming in front of the breakwater. Regarding the trunk-scour study, the experiments indicated that substantial scour may occur at the toe...... at the onshore side. As for the roundheadscour study, it was found that severe scour can be experienced at the roundhead. The scour can occur both at the offshore side of the roundhead and at the back. The one at the offshore side is caused by the combined effect of severe waves and the steady streaming...

  15. Resonant Wave Energy Converters: Concept development

    International Nuclear Information System (INIS)

    The Resonant Wave Energy Converter (REWEC) is a device for converting sea wave energy to electrical energy. It belongs to the family of Oscillating Water Columns and is composed by an absorbing chamber connected to the open sea via a vertical duct. The paper gives a holistic view on the concept development of the device, starting from its implementation in the context of submerged breakwaters to the recently developed vertical breakwaters.

  16. Zonação de comunidade bêntica do entremarés em molhes sob diferente hidrodinamismo na costa norte do estado do Rio de Janeiro, Brasil Zonation of intertidal benthic communities on breakwaters of different hydrodynamics in the north coast of the state of Rio de Janeiro, Brazil

    Directory of Open Access Journals (Sweden)

    Bruno P. Masi

    2008-12-01

    Full Text Available O presente estudo pretende comparar a distribuição vertical da comunidade bêntica na zona entremarés em dois locais compostos por matacões graníticos caracterizados por hidrodinâmica distinta, reflexo da diferença na orientação dos molhes nas praias do Farol de São Tomé (Píer e na Barra do Furado (Barra, norte do Estado do Rio de Janeiro. Quadrados de 400 cm² foram sobrepostos ao longo de três perfis verticais de ambos os sítios e amostrados através do método de fotoquadrats, desde o nível 0,2 m da maré até o limite superior de Littorina spp. O limite superior dos organismos marinhos foi ampliado na Barra (3,8 m em relação ao Píer (2,2 m. Quanto à composição taxonômica, nove espécies foram comuns. Chaetomorpha sp., Chondracanthus teedii (Mertens ex Roth Fredericq e Grateloupia sp. foram exclusivas na Barra, enquanto Tetraclita stalactifera (Lamarck, 1818, Fissurella clench, Gracilaria domingensis (Kützing Sonder ex Dickie e Hypnea musciformis (Wulfen in Jacqu. Lamouroux ocorreram somente no Píer. Em ambos os locais, a riqueza e a diversidade de espécies foram superiores nos quadrados intermediários. Os maiores valores foram registrados na Barra. As maiores diferenças nos agrupamentos entre faixas equivalentes de locais distintos ocorreram na faixa eulitorânea superior, seguida pela faixa eulitorânea inferior e franja sublitorânea. Apenas a orla litorânea não revelou diferença significativa entre os locais, mas uma maior extensão desta franja e da faixa eulitorânea superior era bastante evidente. As demais faixas na Barra do Furado foram caracterizadas em grande parte por espécies típicas de ambientes mais expostos como Chaetomorpha sp. na faixa eulitorânea superior e Perna perna (Linnaeus, 1758 na eulitorânea inferior, além de C. teedii e Ulva fasciata Delile, 1813 na franja sublitorânea. No Píer, as diferentes faixas apresentavam distribuição eqüitativa, refletindo um ambiente menos estressante. As diferenças observadas na distribuição vertical dos organismos bênticos, principalmente na extensão das faixas superiores, evidenciam condições de exposição a ondas variáveis.The present study aims to compare the vertical distribution of intertidal benthic communities in two sites composed by granitic boulders with distint hydrodynamics due to different wave swells at Farol de São Tomé (Pier and Barra do Furado beaches (Barra, both in northern state of Rio de Janeiro. Quadrats of 400 cm² were overlapped along three vertical profiles on each site and were sampled by the photoquadrat method from 0.2 m of the tide level to the upper limit of Littorina spp. The upper limit of the marine organisms was higher at Barra site (3.8 m than at Píer site (2.2 m. Nine species were common to both sites. Chaetomorpha sp., Chondracanthus teedii (Mertens ex Roth Fredericq, and Grateloupia sp. were unique to Barra, whereas Tetraclita stalactifera (Lamarck, 1818, Fissurella clench, Gracilaria domingensis (Kützing Sonder ex Dickie, and Hypnea musciformis (Wulfen in Jacqu. Lamouroux occurred only at Píer boulders. On both sites species richness and diversity were superior at the intermediate quadrats of the intertidal zone. The highest values were recorded at Barra. The most pronounced assemblage differences between equivalent areas of either site occurred on the lower upper eulittoral band followed by the lower eulittoral and the sub-littoral fringe, respectively. The littoral fringe assemblage was the only one that did not show significant differences among the studied sites, yet a larger range of this fringe and the upper eulittoral band at Barra was quite evident. This site was mostly characterized by species of more exposed areas, such as Chaetomorpha sp. and Perna perna (Linnaeus, 1758 on upper and lower eulittoral bands, and by C. teedii and Ulva fasciata Delile, 1813 on the sub-littoral fringe. At Píer, the intertidal zone showed an even distribution, reflecting a less stressful environment. The differences on vertical distribution of the local benthic, particularly in the extent of the upper bands, indicate the variable conditions of wave exposure.

  17. Development of Floating Wave Barriers for Cost Effective Protection of Irrigation and Catfish Pond Levees

    Science.gov (United States)

    Ozeren, Y.; Wren, D. G.; Alonso, C. V.

    2007-12-01

    Earth levees for catfish ponds and irrigation water storage experience significant embankment erosion due to wind generated waves. Large seasonal fluctuations in water level make vegetative bank protection impractical, and other stabilization methods such as the use of old tires or riprap are not acceptable due to ecological and economic concerns. The goal of the present work is to define configurations and construction techniques for inexpensive floating breakwaters made of polyethylene irrigation tubing. Based on wave characteristics measured in an irrigation pond near Lonoke, Arkansas, a laboratory scale wave generating flume was designed, constructed, and used to test multiple wave barrier configurations for regular waves in deep and transitional water depths. Wave transmission characteristics were investigated for the following breakwater arrangements: (1) fully restrained, (2) vertically restrained with a single mooring line, (3) horizontally restrained with a rigid arm hinged at one end, and (4) horizontally restrained with piles at both sides of the breakwater. The test results show that cylindrical pipes can be used effectively as floating breakwaters and that wave transmission characteristics strongly depend on the draft of the breakwater and the mooring configuration. The use of multiple small cylinders instead of a single large one can reduce cost while maintaining the same level of wave attenuation. The wave characteristics measured in the field and the results of laboratory testing resulted in a final design that is to be tested at the prototype scale in an irrigation pond.

  18. Navier-Stokes-Brinkman system for interaction of viscous waves with a submerged porous structure

    Directory of Open Access Journals (Sweden)

    Lemi Guta

    2010-09-01

    Full Text Available In this paper the interaction of a two-dimensional progressive wave train over a submerged rectangular porous breakwater is studied theoretically. For this purpose, the time dependent incompressible Navier-Stokes-Brinkman system is newly derived for wave propagating over submerged breakwater. A staggered grid Finite Volume Method (FVM is used to solve the Navier-Stokes-Brinkman system. The free surface boundary condition and the interfacial boundary conditions between the water and porous media are in complete form. A Volume-of-Fluid (VOF methodology is employed to track the free surface. The validity of present model is verified based on the compressions with the existing experimental results. Having verified the accuracy of the numerical model, the effects of several parameters of a wave and a submerged breakwater were systematically investigated. The results indicate that the wave transformations are affected primarily by the breakwater width and the structure permeability. The numerical results also illustrate that for the porous breakwater, an optimum porosity value seems to exist at which the transmitted wave height is minimized. It has been observed that the transmission coefficient decreases as the permeability increases. However, the results indicate that further increase of the structure permeability beyond the optimal value increase the transmission coefficient.

  19. Wave Interaction with Porous Coastal Structures

    DEFF Research Database (Denmark)

    Jensen, Bjarne

    of structures are rubble mound breakwaters and berm breakwaters where common structural elements are core material, filter layers and armour layers. The armour stones serves as the main protection of the filter and core material against wave action. Therefore the armour stones must maintain stable when exposed...... are also applied as part of investigating and designing breakwaters. The models can provide more detailed information on some topics, such as pressure attenuation through the porous core material, while it is more difficult to simulate the direct destabilisation and movements of individual stones...... the contribution to generation of turbulence, and destabilizing shear stresses, from the wave breaking, the armour layer, and the porous core was singled out. In Chapter 3 a similar detailed approach was taken towards experimental investigation of the pressure induced forces in the filter layers below the main...

  20. RESERCH STUDIES ON THE LOCATION OF A WAVE ENERGY POWER PLANT WITHIN CONSTANTA AREA

    Directory of Open Access Journals (Sweden)

    SAMOILESCU Gheorghe

    2015-05-01

    Full Text Available This paper is based on a research project on the development and installation of the first hydropneumatic plant in the Black Sea. It shows the location and its particularities, existing and previous hydrometeorological conditions, required work, plant qualities and standards to be met. The wave characteristics calculation and the hydrotechnic studies were presented: articulated concrete blocks demolition of the existing breakwater; dredging for the foundation of the plant; accomplish the foundation of the plant; installation of the plant; testing; consolidation and assuring protection of the breakwater; consolidation and assuring protection of the plant. Environmental protection measures are an important part of any research project of this type.

  1. Wave Forces on Crown Walls

    DEFF Research Database (Denmark)

    Pedersen, Jan; Burcharth, H. F.

    1993-01-01

    This paper presents some of the results from a large parametric laboratory study including more than 200 long-duration model tests. The study addresses both the wave forces imposed on the breakwater crown wall as well as the performance of the structure in reducing the wave overtopping. The testing...... programme includes variations of the sea state parameters and of the geometrical configuration of the breakwater and crown wall. Basic relations between forces/overtopping and the varied parameters are examined and preliminary design guidelines for structures within the tested range of variations are...

  2. A Case Study of Nearshore Wave Transformation Processes along the Coast of Mexico near the Laguna Verde Nuclear Power Plant Using a Fast Simulation Method

    Directory of Open Access Journals (Sweden)

    Israel-Enrique Herrera-Díaz

    2010-01-01

    numerical method was developed using a split proposed version of the mild-slope equation and solved by an implicit method in a finite volume grid; this technique easily allows model the wave effects caused by the breakwater building in coastal waters, where industrial and other economic activities take place. Controlled case studies have been made and the results match very well with the reference solution. The capability and utility of the model for real coastal areas are illustrated by application to the breakwater of the Laguna Verde Nuclear Power Plant (LVNPP.

  3. Zeebrugge Model

    DEFF Research Database (Denmark)

    Liu, Zhou; Frigaard, Peter

    This report presents the model on wave run-up and run-down on the Zeebrugge breakwater under short-crested oblique wave attacks. The model test was performed in March-April 2000 at the Hydraulics & Coastal Engineering Laboratory, Aalborg University.......This report presents the model on wave run-up and run-down on the Zeebrugge breakwater under short-crested oblique wave attacks. The model test was performed in March-April 2000 at the Hydraulics & Coastal Engineering Laboratory, Aalborg University....

  4. Description of Model Tests Carried Out by Aalborg University

    DEFF Research Database (Denmark)

    Frigaard, Peter; Schlütter, F.; Andersen, H.

    1996-01-01

    As associated partner, Aalborg University (AU) have participated in different aspects of "the Zeebrugge project". AU has carried out an extensive number of small-scale model tests (1:65) with the Zeebrugge breakwater with the aim of investigating scale-effects.......As associated partner, Aalborg University (AU) have participated in different aspects of "the Zeebrugge project". AU has carried out an extensive number of small-scale model tests (1:65) with the Zeebrugge breakwater with the aim of investigating scale-effects....

  5. Wave Scattering by Double Slotted Barriers in A Steady Current: Experiments

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The adoption of slotted breakwaters can be an ideal option in the protection of very large near-shore floating structures that may extend offshore to a considerable water depth. In this paper, we experimently investigated the behaviour of wave transmission and reflection coefficients of double slotted barriers in the presence of a steady opposing current. The experimental results show that opposing currents have only minor effects on wave reflection, but can significantly reduce the wave transmission through double slotted barriers. The experimental results suggest that coastal currents should be taken into consideration for an economical design of slotted breakwaters.

  6. 3-D Hydraulic Model Testing of the New Roundhead in Suape, Brazil

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Burcharth, Hans F.; Sipavicius, A.;

    This report deals with a three-dimensional model test study of the extension of the breakwater in Suape, Brazil. The roundhead was tested for stability in various sea conditions. The length scale used for the model tests was 1:35. Unless otherwise specified all values given in this report...

  7. Parametric Study of the Roundhead for the New Port of La Coruna at Punta Langosteira

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Haagensen, Per

    The Port of La Coruna, Spain is to be expanded by a new port at Punta Langosteria. The Port Authority of La Coruna has by contract of October 28, 2002, retained the Hydraulic and Coastal Engineering Laboratory at Aalborg University, Denmark, to make a systematic model test study of the breakwater...

  8. 斯里兰卡港口工程明年开始

    Institute of Scientific and Technical Information of China (English)

    M.J.C

    1998-01-01

    Work on the Colombo and Galle port projects will begin next year, Sri Lanka' s deputy finance minister GL Peiris told Parliament recently while presenting the government' s 1999 budget.'The container handling capacity of Colombo' s Queen Elizabeth Quay will be increased to 1 m TEU a year, from 250000 TEU for the present, at a cost of $ 350 m breakwater.

  9. Coastal Erosion and Flooding Hazards on the North Sea Coast at Thyboron, Denmark

    DEFF Research Database (Denmark)

    Sørensen, Per; Sørensen, Carlo Sass; Nielsen, Peter;

    Since a breach of the coastal barrier in 1862, the Thyboron Channel connecting the North Sea and the Lim Fiord has been artificially maintained by construction of breakwaters and groins on the North Sea coast and inside the channel, respectively. Sand nourishment schemes have since the 1980s...

  10. A General Discussion of Problems Related to the Determination of Concrete Armour Unit Stresses Including Specific Results related to Static and Dynamic Stresses in Dolosse

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Liu, Zhou

    1989-01-01

    Recent breakwater failures revealed the shortcomings of the traditional design procedures for concrete armour units. This paper deals with one of them, which can be expressed as the "lack of balance between the hydraulic stability of the armour layer and the mechanical strength or integrity...

  11. New Formula for Stability of Cube Armoured Roundheads

    DEFF Research Database (Denmark)

    Maciñeira, Enrique; Burcharth, Hans F.

    2007-01-01

    Design of armour for rubble mound breakwater roundheads constitutes in many cases a problem due to the limitation of available data and guidelines. The objective of the paper is to present the results of a comprehensive model test study on the stability of cube armoured roundheads, resulting...... in a new stability formula...

  12. Dynamic Response of Coarse Granular Material to Wave Load

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo

    1998-01-01

    waves. The stress conditions in the soil below a foundation exposed to these types of loading are very complex. The key to explain and quantify the soil response beneath a vertical breakwater is to understand the role of the volume changes and to be able to model these correctly. It is shown...

  13. Coastal Changes due to the Construction of Artificial Harbour Entrances and Practical Solutions, including Beach Replenishment

    NARCIS (Netherlands)

    Bijker, E.W.; Van der Leijé, J.P.; Pilon, J.J.; Svasek, J.N.; In 't Veld, J.K.; Verhagen, H.J.

    1981-01-01

    When longshore sediment transport is interrupted by a construction along a coast, e.g harbour moles or a dredged approach channel, the equilibrium of the coastline may be disturbed. When the disruption is caused by breakwaters, the longshore transport that is held back will cause accretion updrift o

  14. 78 FR 75249 - Safety Zone: Google's Night at Sea Fireworks Display, San Francisco Bay, Alameda, CA

    Science.gov (United States)

    2013-12-11

    .... SUPPLEMENTARY INFORMATION: Table of Acronyms DHS Department of Homeland Security FR Federal Register NOAA... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone: Google's Night at Sea Fireworks Display... the breakwater in Alameda, CA in support of Google's Night at Sea Fireworks Displays on December...

  15. The Use of Gabbro Rock Armour in Rubble Mound Structures

    DEFF Research Database (Denmark)

    Beck, J. Blow; Burcharth, H. F.; Danielsen, S. W.;

    2000-01-01

    Throughout several years Gabbro rocks have been used for various coast protective constructions and breakwaters at the North Sea Coast and in inner Danish waters. So far the use of Gabbro has been based solely on calculations from Shore Protection Manuals, i.e without model tests. Compared to ord...

  16. 33 CFR 80.1118 - Marina Del Rey, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Marina Del Rey, CA. 80.1118 Section 80.1118 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1118 Marina Del Rey, CA. (a) A line drawn from Marina Del Rey Breakwater South Light...

  17. Probabilistic Design

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Burcharth, H. F.

    This chapter describes how partial safety factors can be used in design of vertical wall breakwaters and an example of a code format is presented. The partial safety factors are calibrated on a probabilistic basis. The code calibration process used to calibrate some of the partial safety factors...

  18. Marine Structures with Extreme Overtopping Rates

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Frigaard, Peter

    2000-01-01

    In design of sea defence structures like seawalls, breakwaters and dikes, one of the main objectives is to minimize or even eliminate wave overtopping. For this reason numerous investigations have been performed over the past many years to determine the amount of overtopping occurring for typical...... sea defence structures....

  19. Ceodouro project : overall design of an OWC in the new OPorto break water

    Energy Technology Data Exchange (ETDEWEB)

    Martins, E.; Carrilho, L. [EDP, Lisboa (Portugal); Neumann, F. [Centro de Energia das Ondas, Lisboa (Portugal); Ramos, F. Silveira [Consulmar, Lisboa (Portugal); Justino, Paulo Alexandre [INETI/DER, Lisboa, (Portugal); Gato, L.M.C. [Dep. de Engenharia Mecanica, IST, Lisboa, (Portugal); Trigo, L. [Kymaner, S. Domingos de Rana, (Portugal)

    2005-07-01

    The purpose of this work is to present and describe the design approach of the integration of an OWC wave energy plant in a caisson breakwater to be built at the Portuguese northern coast as a promising solution towards sustainable port structures. The presentation of different case study results by Neumann and Sarmento (2000) suggested that such a combination turns out to be a realistic alternative to the traditional coastal protection schemes. The large Portuguese engineering consulting company Consulmar, being responsible for a number of coastal and maritime engineering projects, has accepted the challenge of leading a project for an OWC integration in a caisson breakwater head in Northern Portugal. After the concession of the breakwater construction in 2004, a Consortium has proceeded with preliminary works concerning the integration of an OWC into the breakwater. The Portuguese companies Labelec (EDP group), Kymaner (mechanical components), EFACEC (electrical components) and the Institutions IPTM (Port and Maritime Institute), LNEC (Hydraulic Laboratory), INETI (National Laboratory), IST (University) and the WEC (Wave Energy Centre) are further contributors in the planning phase. This paper presents an overall description of the project, its steps and present state of development.

  20. Zeebrugge Model

    DEFF Research Database (Denmark)

    Jensen, Morten S.; Frigaard, Peter

    In the following, results from model tests with Zeebrugge breakwater are presented. The objective with these tests is partly to investigate the influence on wave run-up due to a changing waterlevel during a storm. Finally, the influence on wave run-up due to an introduced longshore current...

  1. Zeebrugge Model

    DEFF Research Database (Denmark)

    Sclütter, Flemming; Frigaard, Peter; Liu, Zhou

    This report presents the model test results on wave run-up on the Zeebrugge breakwater under the simulated prototype storms. The model test was performed in January 2000 at the Hydraulics & Coastal Engineering Laboratory, Aalborg University. The detailed description of the model is given...

  2. 33 CFR 80.160 - Montauk Point, NY to Atlantic Beach, NY.

    Science.gov (United States)

    2010-07-01

    ... Beach, NY. 80.160 Section 80.160 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... to Atlantic Beach, NY. (a) A line drawn from the Shinnecock Inlet East Breakwater Light to Shinnecock... southernmost extremity of the spit of land at the western end of Oak Beach. (d) A line drawn from Jones...

  3. EPro user manual

    DEFF Research Database (Denmark)

    Meinert, Palle

    EPro is an Erosion PROfiling program, which was original, developed for the Hydraulics and Coastal Engineering group at Aalborg University. Its purpose was/is to make non-contact 3D-measurements of breakwaters, seabed etc. in order to determine erosion. The distances are measured by laser. All me...

  4. Hydraulic Stability of Single-Layer Dolos and Accropode Armour Layers

    DEFF Research Database (Denmark)

    Christensen, M.; Burcharth, H. F.

    1995-01-01

    A new design for Dolos breakwater armour layers is presented: Dolos armour units are placed in a selected geometric pattern in a single layer. A series of model tests have been performed in order to determine the stability of such single-layer Dolos armour layers. The test results are presented a...

  5. Stranden en strandverdediging

    NARCIS (Netherlands)

    Wentholt, L.R.

    1912-01-01

    Description of the Dutch (sandy) coastline, data on high water line, low water line and dunefoot, description of groynes along the coast, effects of harbour moles and breakwaters on the sandy coastline. Detailed analysis on the efficiency of groins along the coast of Holland as well as the Wadden is

  6. Erosion Pressure on the Danish Coasts

    DEFF Research Database (Denmark)

    Sørensen, Carlo Sass; Sørensen, Per; Kroon, Aart;

    by the ocean, coastal erosion issues become increasingly more important to the human values at risk. Along many Danish coastlines, hard structures already act as coastal protection in the form of groins, breakwaters, revetments etc. These eroding coasts however still lack sand and where the public, in general...

  7. THESEUS Deliverable ID2.4

    DEFF Research Database (Denmark)

    Zanuttigh, Barbara; Nørgaard, Jørgen Harck; Andersen, Thomas Lykke;

    . The tested technologies are: - by reducing incident wave energy with a totally innovative solution, wave energy converters placed nearshore (WT 2.1, Part B), and with multi-purpose coastal defences characterised by low environmental impact, as artificial reefs (WT 2.2, Part C) and floating breakwaters (WT2...

  8. THESEUS Deliverable ID2.5

    DEFF Research Database (Denmark)

    Zanuttigh, Barbara; Nørgaard, Jørgen Harck; Ruol, Piero;

    . The tested technologies are: - by reducing incident wave energy with a totally innovative solution, wave energy converters placed near-shore (WT 2.1, Part B), and with multi-purpose coastal defences characterised by low environmental impact, as artificial reefs (WT 2.2, Part C) and floating breakwaters (WT2...

  9. Fieldwork Coastal Engineering: Varna (Bulgaria)

    NARCIS (Netherlands)

    Bos, C.; Burgers, J.J.; Van Dijk, M.; Heeringa, E.; Van den Hengel, D.; Lausman, R.; Oortman, N.; Poot, R.; Segboer, T.; De Sonneville, B.

    2004-01-01

    Research has been carried out in St. Konstantin, Varna, Bulgaria. In the second chapter of this report an Analysis of the Tetra pods on breakwater of the “Sunny Day Marina is presented, where the damage is determined and different approaches are used and compared to determine the significant wave he

  10. Stability of Cubipod Armoured Roundheads in Short Crested Waves

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Andersen, Thomas Lykke; Medina, Josep R.

    The roundhead is generally the most exposed part of the breakwater. Moreover, in case of rubble mound structures the needed armour size is larger than in the adjacent trunk. Typically units of almost double mass are needed in the roundhead if high density stones or concrete are not used in the head....

  11. Durability and Testing of Stone for use in Rubblemound structures

    DEFF Research Database (Denmark)

    Magoon, O.T.; Baird, W.F.; Ahrends, J.P.;

    1993-01-01

    Rubblemound structures protected from wave action by a layer of quarried rock (stones) are the most common form of breakwaters. While extensive guidelines and procedures exist to select the size of stone there is very little information available on procedures to be followed to assure the quality...

  12. Wave Reflection Model Tests

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Larsen, Brian Juul

    The investigation concerns the design of a new internal breakwater in the main port of Ibiza. The objective of the model tests was in the first hand to optimize the cross section to make the wave reflection low enough to ensure that unacceptable wave agitation will not occur in the port. Secondly...

  13. Behaviour of moored ships in harbours

    NARCIS (Netherlands)

    van der Molen, W.

    2006-01-01

    Ports are more and more planned directly facing the ocean. Breakwaters are built to protect the berths against ocean waves. However, protection against long waves, mainly associated with wave groups at the ocean, is much more difficult. Calculations should be performed in the design stage of the por

  14. 33 CFR 322.2 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... 33 CFR 325.2(e) and 33 CFR part 330.) (g) The term artificial reef means a structure which is... States and all other terms relating to the geographic scope of jurisdiction are defined at 33 CFR part..., breakwater, bulkhead, revetment, riprap, jetty, artificial island, artificial reef, permanent...

  15. Feasibility design of a floating airport and estimation of environmental forces on it; Futaishiki kuko no sekkei to kankyo gairyoku no suitei ni kansuru kento

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Y.; Tabeta, S.; Takei, Y. [Yokohama National University, Yokohama (Japan). Faculty of Engineering

    1996-12-31

    A rough design was performed on a floating airport. On this floating structure, environmental external force was estimated, mooring design was carried out, and discussions was given on the position retaining performance important for airport functions and behavior of the floating structure. The discussion was given on cases that the airport is surrounded and not surrounded by floating breakwaters. A floating structure which becomes super-large in size requires considerations on force due to sea level gradient as a result of a tide. Deriving flow condition changes and force acting on the floating structure simultaneously by using numerical calculations makes it possible to estimate current force given with considerations on influence of the flow conditions created by installing the floating airport. Estimation was carried out by using a zone dividing method on wave drifting force acting upon the floating airport. As a result, it was found that installing floating and permeating type breakwaters can reduce the wave drifting force acting on the floating airport. The wave drifting force working on the floating airport can be reduced by installing the floating and permeating type breakwaters to lower levels than when no such breakwaters are installed. The airport may be moored with less number of fenders when the fenders of the same type are used. 18 refs., 10 figs., 5 tabs.

  16. NUMERICAL SOLUTION OF SHORELINE EVOLUTION NEAR COASTAL STRUCTURES

    Institute of Scientific and Technical Information of China (English)

    Cai Ze-wei; Song Xiao-gang; Ye Chun-yang

    2003-01-01

    Numerical analysis was made for shoreline evolution in the vicinity of coastal structures, including spur dike, detached breakwaters. The nonlinear partial differential equation was derived, and numerical solutions were obtained by the finite difference method. The numerical results show good agreement with previous analytical results.

  17. Revised draft environmental statement related to construction of Atlantic Generating Station Units 1 and 2 (Docket Nos. STN 50-477 and STN 50-478)

    International Nuclear Information System (INIS)

    The proposed action is the issuance of a construction permit to Public Service Electric and Gas Company (PDE and G) for the construction of the Atlantic Generating Station (AGS), Units 1 and 2. The AGS is the first nuclear power station in the United States proposed for construction in the offshore waters on the continental shelf. The AHS will be located in the Atlantic Ocean 2.8 miles offshore of Atlantic and Ocean countries. New Jersey, 11 miles northeast of Atlantic City, and will consist of two floating nuclear power plants enclosed in a protective rubble-mound breakwater. Both plants will be identical, of standardized design, and will employ pressurized water reactors to produce up to approximately 3425 megawatts thermal (MWt) each. Steam turbine generators will use this heat to produce up to approximately 1150 megawatts of electrical power (MWe) per unit. The main condensers will be cooled by the flow of seawater drawn from within the breakwater and discharged shoreward and external to the breakwater. This statement identifies various environmental aspects and potential adverse effects associated with the construction and operation of the AGS. Based upon an approximate two-year review period which included a multidisciplined assessment of extensive survey and modeling data, these effects are considered by the staff to be of a generally acceptable nature. Breakwater construction will result in the destruction of 100 acres of benthic infauna (burrowing animals) and the development of a reef-type community on the breakwater. The production of new biomass (standing crop) by the reef community is expected to compensate for the infaunal biomass destroyed by dredging and will contribute mainly to the local sport fishery. 93 figs., 110 tabs

  18. Wave Reflection Coefficient Spectrum

    Institute of Scientific and Technical Information of China (English)

    俞聿修; 邵利民; 柳淑学

    2003-01-01

    The wave reflection coefficient frequency spectrum and directional spectrum for concrete face slope breakwaters and rubble mound breakwaters are investigated through physical model tests in the present study. The reflection coefficients of oblique irregular waves are analyzed by the Modified Two-Point Method (MTPM) proposed by the authors. The results show that the wave reflection coefficient decreases with increasing wave frequency and incident angle or decreasing structure slope. The reflection coefficient frequency spectrum and its variation with Iribarren number are given in this paper. The paper also suggests an empirical 3-dimensional reflection coefficient spectrum, i.e. reflection coefficient directional spectrum, which can be used to illustrate quantitatively the variation of reflection coefficient with the incident angle and the Iribarren number for oblique irregular waves.

  19. Hydraulic Characteristics of Seawave Slot-cone Generator Pilot Plant at Kvitsøy (Norway)

    DEFF Research Database (Denmark)

    Margheritini, Lucia; Vicinanza, Diego; Kofoed, Jens Peter

    2007-01-01

    This paper presents results on wave overtopping and loading on an innovative caisson breakwater for electricity production. The work reported here contributes to the European Union FP6 priority 6.1 (Sustainable Energy System). The design of the structure consists of three reservoirs one on the top...... of each other to optimize the storage of potential energy in the overtopping water. The wave loadings on the main structure can be estimated using experiences from breakwater design, but the differences between the structures is so large that more reliable knowledge is needed. Model tests were carried out...... in a second phase the model has been adapted and equipped with pumps to measure the overtopping flow rates in the single reservoirs. The results of the tests highlight differences between 2D and 3D conditions in terms of pressures and hydraulic efficiency....

  20. Marine and Coastal Morphology: medium term and long-term area modelling

    DEFF Research Database (Denmark)

    Kristensen, Sten Esbjørn

    evolution model and apply them to problems concerning coastal protection strategies (both hard and soft measures). The applied coastal protection strategies involve morphological impact of detached shore parallel segmented breakwaters and shore normal impermeable groynes in groyne fields, and morphological......). Applications of the modelling concept have been collected into 5 papers (1 accepted journal paper, 3 published conference papers and 1 unpublished journal manuscript) which each contain an introduction to the implementation, the motivation for the implementation and the overall results from the application....... The 1.5D model is seen to produce reasonable results when subject to cases with detached breakwaters and groynes. The computational efficiency of the model is however reduced compared to the 1D model, because the increased freedom of the model reduces the maximum stable morphological time step. Bar...

  1. On the Determination of Concrete Armour Unit Stress including Specific Results related to Dolosse

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Howell, G.L.; Liu, Z.

    1991-01-01

    Failures of rubble mound breakwaters armoured with complex types of unreinforced concrete armour units are often due to breakage. This happens when the stresses exceed the material strength. Sufficient parametric studies of the stresses are not yet available to produce design diagrams for structu......Failures of rubble mound breakwaters armoured with complex types of unreinforced concrete armour units are often due to breakage. This happens when the stresses exceed the material strength. Sufficient parametric studies of the stresses are not yet available to produce design diagrams...... and scale effects. Moreover, some results from the Crescent City Prototype Dolosse study are presented and related to results from small-de model tests. A preliminary design diagram for Dolosse ir presented as well....

  2. Stresses in Dolosse

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Liu, Zhou; Howell, Gary L.;

    1991-01-01

    Failures of rubble mound breakwaters armoured with complex types of unreinforced concrete armour units are often due to breakage. This happens when the stresses exceed the material strength. Sufficient parametric studies of the stresses are not yet available to produce design diagrams for structu......Failures of rubble mound breakwaters armoured with complex types of unreinforced concrete armour units are often due to breakage. This happens when the stresses exceed the material strength. Sufficient parametric studies of the stresses are not yet available to produce design diagrams...... for structural integrity. The paper presents the results and the analyses of model tests with 200 kg and 200 g load-cell instrumented Dolosse. Static stresses and wave generated stresses were studied as well as model and scale effects. A preliminary design diagram for Dolosse is presented as well....

  3. Feature articles, thermal power and atomic power. Evaluation technique of antiseismic stability of caisson foundation bulkhead. Karyoku, genshiryoku. Keson shiki gogan no taishin anteisei hyoka gijutsu ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Shimada, M.; Fujitani, M. (Tokyo Electric Power Co., Inc. (Japan))

    1994-05-31

    One of the site construction for nuclear power plant is an offshore artificial island system. In this case, the breakwater bulkhead constructed around the island plays an important role in keeping the safety of the whole site. Accordingly the establishment of evaluation technique of antiseismic stability is also important. This study reproduced the seismic behavior of the breakwater bulkhead by means of model vibration experiment. Various factors affecting the sliding of caisson were considered by taking into account the conventional design method and concept. The experimental results were numerically simulated. For analytically obtaining the settlement of the backward ground due to the sliding of caisson, the applicability of (1) elasto-plastic finite element method using the joint element, and (2) individual element method was investigated. Each of them proved to be effective for quantitatively evaluating the deformation behavior of caisson foundation bulkhead in case of earthquake. 5 refs., 19 figs., 5 tabs.

  4. Surface residues dynamically organize water bridges to enhance electron transfer between proteins

    CERN Document Server

    de la Lande, Aurélien; Řezáč, Jan; Sanders, Barry C; Salahub, Dennis R; 10.1073/pnas.0914457107

    2010-01-01

    Cellular energy production depends on electron transfer (ET) between proteins. In this theoretical study, we investigate the impact of structural and conformational variations on the electronic coupling between the redox proteins methylamine dehydrogenase and amicyanin from Paracoccus denitrificans. We used molecular dynamics simulations to generate configurations over a duration of 40ns (sampled at 100fs intervals) in conjunction with an ET pathway analysis to estimate the ET coupling strength of each configuration. In the wild type complex, we find that the most frequently occurring molecular configurations afford superior electronic coupling due to the consistent presence of a water molecule hydrogen-bonded between the donor and acceptor sites. We attribute the persistence of this water bridge to a "molecular breakwater" composed of several hydrophobic residues surrounding the acceptor site. The breakwater supports the function of nearby solvent-organizing residues by limiting the exchange of water molecul...

  5. Bivalves and Gastropods of the Gulf of Tehuantepec, Mexico: A Checklist of Species with Notes on Their Habitat and Local Distribution

    Directory of Open Access Journals (Sweden)

    Eduardo Ríos-Jara

    2009-01-01

    Full Text Available The taxonomic composition of 160 species of bivalves and gastropods recorded in the Gulf of Tehuantepec is presented with information on their habitat and distribution along 10 different localities of the shoreline and 42 stations of the continental shelf. The species were on sandy and rocky beaches, coastal lagoons, estuaries, mangroves, rocky breakwaters of ports, and shallow subtidal areas (14–47 m depth. A total of 78 bivalve species and 82 gastropod species were recorded. Most of these were associated with sandy and rocky beaches and breakwaters of ports. The estuaries host 30 species and the coastal lagoons only two. In the shallow subtidal there were 18 gastropod species and 40 bivalve species representing 36.3% of all. This study adds 24 bivalve species and 29 gastropod species not recorded in previous studies for a total count of 213 species (102 bivalves and 111 gastropods for Gulf of Tehuantepec.

  6. Shoreline change detection from Karwar to Gokarna - South West coast of India using remotely Sensed data

    Digital Repository Service at National Institute of Oceanography (India)

    Choudhary, R.; Gowthaman, R.; SanilKumar, V.

    , Shoreline Changes, Geomorphology 1. Introduction Coastal zone is very dynamic, being the meeting place of land and sea water. The development in coastal area and subsequent population growth have given rise to problems such as erosion... waves generated by typhoons, inundation and slow coastal erosion. (Moussa Sanea 2007). After the introduction of breakwaters for the port, beach erosion and accretion are considered as critical problems, resulting in damages to the natural set up...

  7. 人工礁に放流した稚ナマコの成長と生残

    OpenAIRE

    古川, 奈未; 古川, 佳道; 山名, 裕介; 柏尾, 翔; 植草, 亮人; 五嶋, 聖治

    2016-01-01

    The objective of this study was to follow growth and survival of the Japanese sea cucumber Apostichopus japonicus juveniles released into artificial reefs, and to verify practical effectiveness of the artifical reef to reduce early disapperance of released juveniles and an overall effect of the juvenile release to enhance the sea cucumber stock. We set up the artifical reefs near a breakwater in Esashi, sowthwestern coast of Hokkaido, where juveniles of sea cucumber were almost unoberved. To ...

  8. "The Way Ahead"

    DEFF Research Database (Denmark)

    Burcharth, Hans F.

    It is true for all structures that the design and the location affects the loads. Breakwaters are extreme examples of this thesis, since even small variations in waterdepth, orientation slope etc. produce large variations in the load. As the dominant load is stochastic in nature and exhibits extr...... basic knowledge. One could say that the available knowledge did not reach the engineers on time. One way ahead is, therefore, and always has been, to ensure good communication of up-to-date knowledge....

  9. Distribution of Wave Loads for Design of Crown Walls in Deep and Shallow Water

    DEFF Research Database (Denmark)

    Nørgaard, Jørgen Quvang Harck; Andersen, Thomas Lykke

    2014-01-01

    This paper puts forward a new method to determine horizontal wave loads on rubble mound breakwater crown walls with specific exceedance probabilities based on the formulae by Nørgaard et al. (2013) as well as presents a new modified version of the wave run-up formula by Van der Meer & Stam (1992...... will be used in future studies in more detailed investigations on the influence from the load exceedance probability on the stability of crown walls....

  10. Risk-based Optimization and Reliability Levels of Coastal Structures

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Burcharth, H. F.

    Identification of optimum reliability levels for coastal structures is considered. A class of breakwaters is considered where no human injuries can be expected in cases of failure. The optimum reliability level is identified by minimizing the total costs over the service life of the structure...... on the minimumcost reliability levels is investigated for different values of the real rate of interest, the service lifetime, the downtime costs due to malfunction and the decommission costs....

  11. Risk-based Optimization and Reliability Levels of Coastal Structures

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Burcharth, Hans F.

    2005-01-01

     Identification of optimum reliability levels for coastal structures is considered. A class of breakwaters is considered where no human injuries can be expected in cases of failure. The optimum reliability level is identified by minimizing the total costs over the service life of the structure...... on the minimumcost reliability levels is investigated for different values of the real rate of interest, the service lifetime, the downtime costs due to malfunction and the decommission costs....

  12. Low to high performance recycled cementitious materials: case studies

    OpenAIRE

    Etxeberria Larrañaga, Miren

    2015-01-01

    In this work, four real case studies using concrete produced with recycled aggregates are described. The four real cases carried out in Barcelona are: 1) Pavement filling with control low strength material (CLSM) employing fine recycled aggregates, 2) pervious recycled aggregate concrete employing coarse mixed recycled aggregates in the works undertaken at Cervantes park; 3) Concrete blocks produced employing recycled and slag aggregates as well as sea water for a new breakwater dyke and 4) R...

  13. Wave Pressures and Loads on a Small Scale Model of the Svåheia SSG Pilot Project

    DEFF Research Database (Denmark)

    Buccino, Mariano; Vicinanza, Diego; Ciardulli, Francesco;

    2011-01-01

    The paper reports on 2D small scale experiments conducted to investigate wave loadings acting on a pilot project of device for the conversion of wave energy into electricity. The conversion concept is based on the overtopping principle and the structure is worldwide known with the acronym SSG...... interval. It is also shown that two calculation methods widely employed in the Japanese design practice of vertical face breakwaters, could be used to achieve safe estimates of the hydrodynamic loadings....

  14. Analysis of Short-Term Steel Corrosion Products Formed in Tropical Marine Environments of Panama

    OpenAIRE

    Juan A. Jaén; Josefina Iglesias; Cecilio Hernández

    2012-01-01

    A low-carbon steel A-36 and two conventional weathering steels A-588 and COR-420 exposed at four atmospheric test stations located in (i) Tocumen, an urban site near the Pacific Ocean, (ii) Sherman-Open, (iii) Sherman-Coastal, and (iv) Sherman-Breakwater on the Caribbean coast of Panama. Kinetics of the short-term atmospheric corrosion process and the relationship with exposure time and environmental characteristics of each site were investigated. The atmospheric exposure conditions, particul...

  15. Hindcasting of storm waves using neural networks

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, S.; Mandal, S.

    is available for short periods for some places along the coasts. The spatial wave information of numerical wave forecasting schemes is useful and attractive in many applications, but it needs elaborate meteorological and oceanographic data and involves... there is an element of uncertainty when wind fields are used for the hindcasting of engineering are sea level prediction (Vaziri, 1997), estuarine instabilities (Grubert, 1995), stability analysis of rubble mound breakwaters (Mase et al., 1995), wave forecasting (Deo...

  16. Spatial Distribution of Wave Pressures on Seawave Slot-Cone Generator

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Margheritini, Lucia; Frigaard, Peter

    2009-01-01

    This paper presents results on loading acting on an innovative caisson breakwater for electricity production. The work reported here is part of the European Union Sixth Framework programme priority 6.1 (Sustainable Energy System), contract 019831, titled "Full-scale demonstration of robust and hi...... Kvitsøy near Stavanger, Norway. The research study is intended to be of direct use to engineers analyzing design and stability of the pilot plant....

  17. Inception Report The Preparatory Survey on the Project for Fisheries Pormotion in Republic of Ghana

    OpenAIRE

    Ghana Ports and Harbours Authority

    2013-01-01

    Challenges the fishing ports of Ghana, notably Sekondi Port include the congestion and the deteriorating efficiency due to the increase of users and decreasing quality of catch due to the shortage and ageing of landing facilities, fish handling sheds and ice-making facilities. The Government of Ghana made a request to Japan for an extension of the wharf, construction of additional breakwater, cold storage and ice-making facility at Sekondi Fishing Port in 2010 in order to overcome these chall...

  18. Spatio-temporal evolution of shoreline changes along the coast between sousse- Monastir (Eastearn of Tunisia)

    Science.gov (United States)

    Fathallah, S.; Ben Amor, R.; Gueddari, M.

    2009-04-01

    Spatio-temporal evolution of shoreline Changes along the coast between Sousse-Monastir (Eastern of Tunisia). Safa Fathallah*, Rim Ben Amor and Moncef Gueddari Unit of Research of Geochemistry and Environmental Geology. Faculty of Science of Tunis, University of Tunis El Manar, 2092. (*) Corresponding author: safa_fathallah@yahoo.fr The coast of Sousse-Monastir in eastern of Tunisia, has undergone great changes, due to natural and anthropic factors. Increasing human use, the construction of two ports and coastal urbanization (hotels and industries) has accelerated the erosion process. The coastal defense structures (breakwaters and enrockment), built to protect the most eroded zone are efficient, but eroded zones appeared in the southern part of breakwaters. Recent and historic aerial photography was used to estimate, observe, and analyze past shoreline and bathymetric positions and trends involving shore evolution for Sousse-Monastir coast. All of the photographs were calibrated and mosaicked by Arc Map Gis 9.1, the years used are 1925, 1962, 1988, 1996, and 2001 for shoreline change analysis and 1884 and 2001 for bathymetric changes. The analyze of this photographs show that the zone located at the south of breakwater are mostly eroded with high speed process (2m/year). Another zone appears as eroded at the south part of Hamdoun River, with 1,5m/year erosion speed . Keywords: Shoreline evolution, defense structures, Sousse-Monastir coast, Tunisia.

  19. NUMERICAL SIMULATIONS OF NONLINEAR WAVE TRANSFORMATION AROUND WAVE-PERMEABLE STRUCTURE

    Institute of Scientific and Technical Information of China (English)

    Li Xi; YAN Yi-xin

    2005-01-01

    The problem of wave partial/full reflection and transmission by wave-permeable structure is approached by solving the shape-related function with focus on the understanding of wave attenuation.2D depth-averaged Boussinesq type wave equations are given with new damping item in simulating the nonlinear wave transmission through wave-permeable structure.1D wave equation is examined to give the analytical expression of the absorbing coefficient, and is compared with laboratory data in flume to calibrate the coefficients, and the expression is applied directly in modified Boussinesq type equations.Compared with wave basin data for various incident wave conditions,the accurate predictions of combined diffraction-refraction effects in simulating nonlinear wave going through wave-permeable breakwater in the engineering application can be obtained.It shows that wave-permeable breakwaters with proper absorbing effects can be used as an effective alternative to massive gravity breakwaters in reduction of wave transmission in shallow water.

  20. EXPERIMENTAL STUDY OF WAVE FLOWS AROUND THE FINITE LENGTH VERTICAL WALL

    Directory of Open Access Journals (Sweden)

    Tran Long Giang

    2012-10-01

    Full Text Available Construction of breakwater structures of modern seaports requires computational models describing interaction of waves with structural elements of ports. The model should be based on numerical hydrodynamic models that contemplate all constituents of interaction between waves and structures, including those at various stages of construction. The above model makes it possible to have construction works performed in accordance with the pre-developed plan. Experimentalresearch of the behaviour of breakwater structures is to be conducted in laboratories. A scaled natural model is to be used for the above purpose to verify the model behaviour. The authors consider the methodology and results of experiments involving models of wave loads produced on vertical breakwater structures at various stages of their construction. On the basis of the experiments conducted by the authors, it is discovered that the value of the total wave force, that the vertical wall is exposed to, increases along with the wall length in the event of a constant wave mode, which is natural. However, the per-meter value of the wave force increases along with the increase in the length of the wall until it reaches the value of the length of a transverse obstacle divided by the length of waves equal to 0.28; thereafter, the wave force goes down. The authors assume that this phenomenon is caused by the change in the nature of interaction between waves and an obstacle and a transition from a diffraction-free flow to a diffraction flow. The authors believe that further researches are necessary to explore the phenomenon.

  1. EPro Non-contact erosion profiling

    DEFF Research Database (Denmark)

    Meinert, Palle

    Pro is a profiling program build to measure the same surface or work piece multiple times and track changes due to erosion. It was developed during 2001 - 2002 at Aalborg University and was part of a Master of Science project dealing with stability of rubble mound breakwaters. The goal was to...... automate the measuring of profiles in order to save manpower and to increase the number of possible measure points. Additional requirement was that measurements should be done in a non-contact way and that the measuring should not be hindered by the presence of water....

  2. Stability of Armour Units in Oscillatory Flow

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Thompson, A. C.

    1983-01-01

    As part of a program to study the hydraulics of wave attack on rubble mound breakwaters tests were made on model armour units in a steady flow through a layer laid on a slope. The flow angle has little effect on stability for dolosse or rock layers. The head drop at failure across each type...... of layer is similar but the dolosse layer is more permeable and fails as a whole. There was no viscous scale effect. These results and earlier tests in oscillating flow suggest a 'reservoir' effect is important in the stability in steep waves....

  3. A rational methodology for the study of foundations for marine structures; Una metdologia racional para el estudio de cimentaciones de estructuras marinas

    Energy Technology Data Exchange (ETDEWEB)

    Mira Mc Willams, P.; Fernandez-Merodo, J. A.; Pastor Perez, M.; Monte Saez, J. L.; Martinez Santamaria, J. M.; Cuellar Mirasol, V.; Martin Baanante, M. E.; Rodriguez Sanchez-Arevalo, I; Lopez Maldonando, J. D.; Tomas Sampedro, A.

    2011-07-01

    A methodology for the study of marine foundations is presented. The response in displacements, stresses and pore water pressures in obtained from a finite element coupled formulation. Loads due to wave action of the foundation are obtained from a volume of fluid type fluid-structure interaction numerical model. Additionally, the methodology includes a Generalized Plasticity based constitutive model for granular materials capable of representing liquefaction fenomena of sands subjected to cyclic loading, such as those frequently appearing in the problems studied. Calibration of this model requires a series of laboratory tests detailed herein. This methodology is applied to the study of the response of a caisson breakwater foundation. (Author) 10 refs.

  4. Stability of Armour Units in Flow Through a Layer

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; C. Thompson, Alex

    1984-01-01

    As part of a program to study the hydraulics of wave attack on rubble mound breakwaters tests were made on model armour units in a steady flow through a layer laid on a slope. The flow angle has little effect on stability for dolosse or rock layers. The head drop at failure across each type of la...... of layer is similar but the dolosse layer is more permeable and fails as a whole. There was no viscous scale effect. These results and earlier tests in oscillating flow suggest a 'reservoir' effect is important in the stability in steep waves....

  5. Determination of Ice Characteristics for Marine Hydroengineering Structures

    Energy Technology Data Exchange (ETDEWEB)

    Kantarzhi, I. G., E-mail: kantardgi@yandex.ru [Moscow State University of Civil Engineering (MSGU) (Russian Federation); Maderich, V. S., E-mail: vladmad@gmail.com; Koshebutskii, V. I., E-mail: koshik1@gmail.com [Ukrainian Center of Environmental and Water Projects (UTsÉVP) (Ukraine)

    2016-01-15

    Problems and potential approaches to determining ice characteristics for sea hydroengineering structures design are considered. A system for numerical modeling of ice dynamics is presented. The system may be used to define ice characteristics on approaches to structures with due regard for local hydrometeorological conditions and ice loads on structures. System application examples are presented for determining computational scenarios for ice loads at structures of the Pevek floating nuclear power plant (FNPP), as well as for the breakwater pier under reconstruction in Vanino. A scenario approach is used to determined ice loads.

  6. Prediction of Settlements of Soft Clay Subjected to Long-Term Dynamic Load

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    -Presented is the numerical analysis of settlements of soft soil by a 2-D dynamic effective stress FEM method. The model based on the results of cyclic triaxial tests on the reconstituted soft Ariake clay is used to predict the wave induced excess pore water pressure and residual strain of soft clay. The settlements of two types of breakwaters on the soft clay under ocean wave load, a low embankment subjected to traffic load and the tunnel surrounded by soft clay in Shanghai subjected to locomotive load are calculated as examples.

  7. WAVE TRANSMISSION AND REFLECTION DUE TO A THIN VERTICAL BARRIER

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A numerical method, the boundary fitted coordinate method (BFC),was used to investigate the transmission and reflection of water waves due to a rigid thin vertical barrier descending from the water surface to a depth, i. e. , a curtain-wall type breakwater. A comparison between the present computed results and previous experimental and analytical results was carried out which verifies the prediction of the BFC method. Wave transmission and reflection due to the barrier were computed, and the transmission and refiection coefficients were given in a figure.

  8. Nonlinear wave-structure interactions with a high-order Boussinesq model

    DEFF Research Database (Denmark)

    Fuhrman, David R.; Bingham, Harry; Madsen, Per A.

    2005-01-01

    This paper describes the extension of a finite difference model based on a recently derived highly accurate Boussinesq formulation to include domains having arbitrary piecewise-rectangular bottom-mounted (surface-piercing) structures. The resulting linearized system is analyzed for stability on a...... system is receptive to dissipation, and these problems can be overcome in practice using high-order filtering techniques. The resulting model is verified through numerical simulations involving classical linear wave diffraction around a semi-infinite breakwater, linear and nonlinear gap diffraction, and...

  9. A coupled soil-pore fluid formulation for modeling soil liquefaction and cyclic mobility in seabed using the finite volume method

    DEFF Research Database (Denmark)

    Tang, Tian; Roenby, Johan; Hededal, Ole

    The stability of offshore structures, such as wind turbine foundations, breakwaters, and immersed tunnels can be strongly affected by the liquefaction and cyclic mobility phenomena in the seabed. Our goal is to develop a numerical code for analysis of these situations. For this purpose, we start...... by formulating the strong interactions between soil skeleton and the pore fluid via a coupled set of partial differential equations. A single bounding surface soil model capable of simulating the accumulations of pore pressures, strains, dilatancy, and strain „softening‟, is then adopted for quantifying...

  10. Oluvil Port Development Project.:3rd party opinion on report by Lanka Hydraulic Institute Ltd: Oluvil Port Development Project: Studies on Beach Erosion, June 2011.

    OpenAIRE

    Frigaard, Peter; Margheritini, Lucia

    2011-01-01

    Oluvil Port Development Project is the first development of a large port infrastructure in the entire eastern coastline of Sri Lanka. The project is supported by the Danish Foreign Ministry. Feasibility studies and detailed design studies were carried out by Lanka Hydraulic Institute Ltd during the years 1995 to 2003. The design was reviewed by COWI a/s. Construction of the port was started in 2008. MT Højgaard a/s acted as contractor. The outer breakwaters were constructed as first part of t...

  11. Stability of Cubipod Armoured Roundheads in Short Crested Waves

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Andersen, Thomas Lykke; Medina, Josep R.

    2011-01-01

    The paper presents a comparison of the stability of concrete cube armour and Cubipod armour in a breakwater roundhead with slope 1:1.5, exposed to both 2-D (long-crested) and 3-D (short-crested) waves. The model tests were performed at the Hydraulics and Coastal Engineering Laboratory at Aalborg...... University, Denmark. The model tests showed that Cubipod armour is more stable than cube armour when exposed to longer waves (steepness approx. 0.025) and has equal stability to cubes in shorter waves. The Cubipod armour layer contained due to its high porosity approximately 6-17% less concrete than the cube...

  12. Wave Reflection in 3D Conditions

    DEFF Research Database (Denmark)

    Zanuttigh, Barbara; Andersen, Thomas Lykke

    2010-01-01

    Based on recent experiments carried out in wave basin on breakwaters with armour layer of rocks and cubes, this paper examines the dependence of the reflection coefficient on wave directional spreading and obliquity. Results suggest that long-crested and short-crested waves give similar reflection....... The reflection coefficient is markedly dependent on the wave angle of incidence. The performance of formulae available in the literature is checked against the new dataset and a significant improvement is proposed by including the wave obliquity factor that appears in the traditional expression...

  13. Port of Altamira, Mexico

    OpenAIRE

    Croonen, K.; Froeling, D.; Marbus, G.; Bemmel, M. van

    2006-01-01

    Master project report. The Port of Altamira is one of the fast growing ports in the world and is together with Veracruz and Coatzacoalcos one of the biggest ports of Mexico at the Gulf coast. It is an industrial Port with a lot of potential for expanding. However, the breakwaters of the Port extending into the sea caused severe erosion at the downdrift side of the Port (south side). This ongoing erosion is threatening a precious lagoon and some important land. The erosion can also cause a bre...

  14. Wave interaction with large roughness elements on an impermeable sloping bed

    DEFF Research Database (Denmark)

    Jensen, Bjarne; Christensen, Erik Damgaard; Sumer, B. Mutlu

    2012-01-01

    The present paper presents the results of an experimental and numerical investigation of the flow between large roughness elements on a steep sloping impermeable bed during wave action. The setup is designed to resemble a breakwater structure. The work is part of a study where the focus is on the......The present paper presents the results of an experimental and numerical investigation of the flow between large roughness elements on a steep sloping impermeable bed during wave action. The setup is designed to resemble a breakwater structure. The work is part of a study where the focus...... is on the details in the porous core flow and the armour layer flow i.e. the interaction between the two flow domains and the effect on the armour layer stability. In order to isolate the processes involved with the flow in the porous core the investigations are first carried out with a completely impermeable bed...... and successively repeated with a porous bed. In this paper the focus is on the impermeable bed. Results are obtained experimentally for flow and turbulence between the roughness elements on the sloping bed. Numerical simulations have reproduced the experimental results with good agreements and can hereby add more...

  15. Interviewing insights regarding the fatalities inflicted by the 2011 Great East Japan Earthquake

    Directory of Open Access Journals (Sweden)

    M. Ando

    2013-09-01

    Full Text Available One hundred fifty survivors of the 11 March 2011 Great East Japan Earthquake (Tohoku-oki earthquake (Mw = 9.0 were interviewed to study the causes of deaths from the associated tsunami in coastal areas of Tohoku. The first official tsunami warning underestimated the height of the tsunami and 40% of the interviewees did not obtain this warning due to immediate blackouts and a lack of communication after the earthquake. Many chose to remain in dangerous locations based on the underestimated warning and their experiences with previous smaller tsunamis and/or due to misunderstanding the mitigating effects of nearby breakwaters in blocking incoming tsunamis. Some delayed their evacuation to perform family safety checks, and in many situations, the people affected misunderstood the risks involved in tsunamis. In this area, three large tsunamis have struck in the 115 yr preceding the 2011 tsunami. These tsunamis remained in the collective memory of communities, and numerous measures against future tsunami damage, such as breakwaters and tsunami evacuation drills, had been implemented. Despite these preparedness efforts, approximately 18 500 deaths and cases of missing persons occurred. The death rate with the age of 65 and above was particularly high, four times higher than that with other age groups. These interviews indicate that deaths resulted from a variety of reasons, but if residents had taken immediate action after the major ground motion stopped, most residents might have been saved. Education about the science behind earthquakes and tsunamis could help save more lives in the future.

  16. Holocene morphogenesis of Alexander the Great's isthmus at Tyre in Lebanon

    Science.gov (United States)

    Marriner, Nick; Morhange, Christophe; Meulé, Samuel

    2007-05-01

    In 332 B.C., Alexander the Great constructed an ≈1,000-m-long causeway to seize the offshore island of Tyre. The logistics behind this engineering feat have long troubled archaeologists. Using the Holocene sedimentary record, we demonstrate that Alexander's engineers cleverly exploited a shallow proto-tombolo, or sublittoral sand spit, to breach the offshore city's defensive impregnability. We elucidate a three-phase geomorphological model for the spit's evolution. Settled since the Bronze Age, the area's geological record manifests a long history of natural and anthropogenic forcings. (i) Leeward of the island breakwater, the maximum flooding surface (e.g., drowning of the subaerial land surfaces by seawater) is dated ≈8000 B.P. Fine-grained sediments and brackish and marine-lagoonal faunas translate shallow, low-energy water bodies at this time. Shelter was afforded by Tyre's elongated sandstone reefs, which acted as a 6-km natural breakwater. (ii) By 6000 B.P., sea-level rise had reduced the dimensions of the island from 6 to 4 km. The leeward wave shadow generated by this island, allied with high sediment supply after 3000 B.P., culminated in a natural wave-dominated proto-tombolo within 1-2 m of mean sea level by the time of Alexander the Great (4th century B.C.). (iii) After 332 B.C., construction of Alexander's causeway entrained a complete anthropogenic metamorphosis of the Tyrian coastal system.

  17. The SSG Wave Energy Converter: Performance, Status and Recent Developments

    Directory of Open Access Journals (Sweden)

    Mariano Buccino

    2012-01-01

    Full Text Available The Sea-wave Slot-cone Generator (SSG is a Wave Energy Converter based on the wave overtopping principle; it employs several reservoirs placed on top of each other, in which the energy of incoming waves is stored as potential energy. Then, the captured water runs through turbines for electricity production. The system works under a wide spectrum of different wave conditions, giving a high overall efficiency. It can be suitable for shoreline and breakwater applications and presents particular advantages, such as sharing structure costs, availability of grid connection and recirculation of water inside the harbor, as the outlet of the turbines is on the rear part of the system. Recently, plans for the SSG pilot installations are in progress at the Svaaheia site (Norway, the port of Hanstholm (Denmark and the port of Garibaldi (Oregon, USA. In the last-mentioned two projects, the Sea-wave Slot-cone Generator technology is integrated into the outer harbor breakwater and jetty reconstruction projects. In the last years extensive studies have been performed on the hydraulic and the structural response of this converter, with the aim of optimizing the design process. The investigations have been conducted by physical model tests and numerical simulations and many results have been published on both conference proceedings and journals. The main scope of this paper is reviewing the most significant findings, to provide the reader with an organic overview on the present status of knowledge.

  18. Interviewing insights regarding the fatalities inflicted by the 2011 Great East Japan Earthquake

    Science.gov (United States)

    Ando, M.; Ishida, M.; Hayashi, Y.; Mizuki, C.; Nishikawa, Y.; Tu, Y.

    2013-09-01

    One hundred fifty survivors of the 11 March 2011 Great East Japan Earthquake (Tohoku-oki earthquake) (Mw = 9.0) were interviewed to study the causes of deaths from the associated tsunami in coastal areas of Tohoku. The first official tsunami warning underestimated the height of the tsunami and 40% of the interviewees did not obtain this warning due to immediate blackouts and a lack of communication after the earthquake. Many chose to remain in dangerous locations based on the underestimated warning and their experiences with previous smaller tsunamis and/or due to misunderstanding the mitigating effects of nearby breakwaters in blocking incoming tsunamis. Some delayed their evacuation to perform family safety checks, and in many situations, the people affected misunderstood the risks involved in tsunamis. In this area, three large tsunamis have struck in the 115 yr preceding the 2011 tsunami. These tsunamis remained in the collective memory of communities, and numerous measures against future tsunami damage, such as breakwaters and tsunami evacuation drills, had been implemented. Despite these preparedness efforts, approximately 18 500 deaths and cases of missing persons occurred. The death rate with the age of 65 and above was particularly high, four times higher than that with other age groups. These interviews indicate that deaths resulted from a variety of reasons, but if residents had taken immediate action after the major ground motion stopped, most residents might have been saved. Education about the science behind earthquakes and tsunamis could help save more lives in the future.

  19. Indoor atmospheric corrosion of conventional weathering steels in the tropical atmosphere of Panama

    Science.gov (United States)

    Jaén, Juan A.; Iglesias, Josefina; Adames, Olga

    2014-01-01

    One year indoor atmospheric corrosion examinations have been carried out on two conventional weathering steels for a year, at two test sites, Tocumen and Sherman Breakwater in Panama. They are environmentally classified by ISO 9223 as S1P0 τ 4 and S3P0 τ 5, respectively. In this humid-tropical marine climate corrosion rates are rather high, especially at Sherman Breakwater test site, mainly due to the high deposition of chloride, among other environmental conditions. Our results indicate that indoor corrosion is highly determined by the time of wetness and chloride ions. A-588 weathering steel corroded at a generally lower rate than COR-420 weathering steel. Rust characterization was performed by XRD, FTIR, and Mössbauer spectroscopy. Lepidocrocite, goethite, maghemite and akaganeite were found as corrosion products. Akaganeite is only detected when high chlorides deposition rates are obtained, and no washing effect occurs. This phase, together with maghemite, is obtained when there is greater aggressiveness in the environment.

  20. OBLIQUE WATER WAVES IMPACTING ON A THIN POROUS WALL WITH A PARTIAL-SLIPPING BOUNDARY CONDITION

    Institute of Scientific and Technical Information of China (English)

    HSU Hao-Jen; HUANG Liang-Hsiung

    2011-01-01

    When an incoming water wave is parallel to a porous breakwater, a paradoxical phenomenon exists in that by strictly following the potential flow boundary condition of normal flux continuity on the interfaces, the water wave permeates the wall completely, regardless of breakwater porosity. To account for this paradoxical phenomenon when solving the problem of water waves obliquely impacting on a thin porous wall, a new partial-slipping boundary condition on the thin porous wall for potential flow is proposed. Analytical results show that when the water wave is parallel to a thin porous wall (i.e., the incident angle equals to 90°),the transmitted wave side remains quiescent, i.e., the transmitted wave side does not capture any wave energy when no viscous effect exists. This reveals that the above-mentioned paradoxical phenomenon disappears. The viscous boundary layer effect is also investigated in this study, which provides proper boundary conditions on a thin porous wall for viscous flows and detailed flow information.

  1. Analysis on the applicability of VLFS for China

    Institute of Scientific and Technical Information of China (English)

    CHEN Han-bao

    2010-01-01

    With the advantages on rapid construction, no limitation of extent ,less influence on environment, the VLFS has been turned into the focus of coastal and offshore engineering studying.As the platform,VLFS was built as airport,huge oil house etc,and would play the role of ocean economics,politics and military.The restrictive condition of VLFS is strong wave by monsoon, seismic, serious bomb etc.The floating breakwater should be put forward to shelter VLFS.The analysis of wave condition including typhoon route,archipelago and water - depth is performed in this paper.The advantage and disadvantage are compared between VLFS and the marine structure from land.

  2. On the Degradation of Concrete in Marine Structures

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Hofman Frisch, P.; Freisleben, P.;

    1985-01-01

    practice and inherent problems are dealt with. Some recommendations on concrete specifications and production technique are also presented. The second part of the paper presents conventional concrete problems as observed in quaywall structures in harbour basins. On the background of the first two parts......Concrete is a cheap and extremely handy material and as such used extensively also in marine structures. Everybody dealing with this material knows examples of concrete apparently of almost infinite durability but also examples where serious degradation started shortly after completion...... of the structure. It is a fact that despite the tremendous amount of research and despite the material having been used for generations, the difference between success and failure is still small. The paper is in three parts. In the first part, which deals with concrete in breakwater structures, the conventional...

  3. Analysis of some solutions to protect the western tombolo of Giens

    CERN Document Server

    Van Than, Van; Liardet, Pierre; Leandri, Didier

    2014-01-01

    The tombolo of Giens is located in the town of Hyeeres (France). We recall the history of coastal erosion, and proeminent factors affecting the evolution of the western tombolo. We then discuss the possibility of stabilizing the western tombolo. Our argumentation relies on a coupled model integrating swells, currents, water levels and sediment transport. We present the conclusions of the simulations of various scenarios, including pre-existing propositions from coastal engineering offices. We conclude that beach replenishment seems to be necessary but not sufficient for the stabilization of the beach. Breakwaters reveal effective particularly in the most exposed northern area. Some solutions fulfill conditions so as to be elected as satisfactory. We give a comparative analysis of the efficiency of 14 alternatives for the protection of the tombolo.

  4. Final environmental statement related to the proposed manufacture of floating nuclear power plants: (Docket No. STN 50-437): Part 2, A generic environmental statement considering the siting and operation of floating nuclear power plants

    International Nuclear Information System (INIS)

    The proposed action is the issuance of a manufacturing license to Offshore Power Systems for the startup and operation of a proposed manufacturing facility located at Blount Island, Jacksonville, Florida (Docket No. STN 50-437). No nuclear fuel will be handled or stored at the manufacturing site. The plants will be fueled after they have been towed to and moored within protected basins at specific locations designated by the purchaser and after an operating license has been issued by the Nuclear Regulatory Commission. Each nuclear generating plant, mounted on a floating platform, has a net capacity of 1150 MWe. This energy is provided by a pressurized water reactor steam supply system consisting of a Westinghouse four-loop 3425-MWt unit with an ice-condenser containment system. When one or more of these units is located within a single breakwater, the installation is designated an offshore power station. 226 figs., 95 tabs

  5. Design, Construction, Reliability and Hydraulic Performance of an Innovative Wave Overtopping Device

    DEFF Research Database (Denmark)

    Frigaard, Peter; Andersen, Thomas Lykke; Margheritini, Lucia;

    2008-01-01

    The SSG (Sea Slot-cone Generator) is a wave energy converter of the overtopping type. The structure consists of a number of reservoirs one on the top of each others above the mean water level, in which the water of incoming waves is stored temporary. In each reservoir, expressively designed low...... head hydroturbines are converting the potential energy of the stored water into power. A yearly energy production of 320 MWh is foreseen for a 10 meter wide section. A key to success for the SSG will be the low cost of the structure and its robustness. During the last 2 years such a 1350 tonnes...... is that some breakwaters under design are being investigated as a possible places for integrating the SSG structure. The paper describes the concept of the SSG wave energy converter, the structure and the studies that led to its design....

  6. Mirmecofauna (Hymenoptera, Formicidae de Duas Marismas do Estuário da Lagoa dos Patos, RS: Diversidade, Flutuação de Abundância e Similaridade como Indicadores de Conservação

    Directory of Open Access Journals (Sweden)

    Cristiane Bolico

    2012-03-01

    Abstract. The aim of this investigation was to assess the myrmecofauna of two distinct salt marshes and to estimate the diversity, similarity, as well as to estimate the effects of temperature, relative humidity and rainfall on the fluctuation patterns of these insects. Additionally, the species that act as environmental indicators were recognized. The study was conducted in two salt marshes located in the Patos Lagoon Estuary: Torotama’s Island and West Breakwater. A total of 853 ants were sampled, distributed in 19 genera. Both marshes showed similar diversity and abundance, Ds = 0.958 and I = 0.042 in Torotama’s Island and Ds = 0.8889 and I = 0.111 in West Break Water. Trends in ant composition coincided in both areas, with a peak during the warmer months. Areas showed no similarity, due to anthropogenic factors and species’ biology. Groups considered as biomarkers were recorded in the samples, providing parameters for environmental conservation.

  7. Converting old shore protection structures into softer defence

    Science.gov (United States)

    Pranzini, Enzo

    2010-05-01

    Beach erosion has been affecting several developed countries since the middle of 19th century, which led to the construction of many different protection structures. These frequently proved to be ineffective locally, while being negative for downdrift coastal segments. In addition, such defence structures modified the coastal morphology, often transforming a sandy beach into a rocky coast. Softer shore protection projects have been developed in the past years, mostly accompanied by beach nourishment that uses quarried material or shelf sediments. This proved to be efficient in defending the beach, without negative fallouts on unprotected sectors. These techniques can be easily applied to beaches where no "archeaostructures" had been realized before. On the other hand, difficulties arise when such "old style" structures are to be replaced with softer techniques, since traditional hard defences usually cause such changes to beach profile that innovative ones become "too soft". Due to profile deepening in front of reflective structures, wave shoaling is reduced and energy dissipation concentrated in a narrow beach band. Restoring a milder profile needs a large amount of sediments and fine sands are not stable under those conditions. The new challenge for coastal engineers, coastal geomorphologists and coastal planners is managing the transition from old archaeostructures to new soft shore protection techniques. This process requires years of progressive adaptation - an unsuitable timing for politicians who demand fast results to be sold during the next elections. In Italy, along the Tuscany coast, where more than two kilometres of breakwaters protect each kilometre of coast, such a process has been initiated after a long phase of stakeholder participation in order to overcome public scepticism towards "invisible" defences. Detached breakwaters were lowered below sea level at Follonica and Marina di Pisa, while the number of groins is to be reduced at Marina di Massa

  8. Optimization of power take-off equipment for an oscillating water column wave energy plant

    Energy Technology Data Exchange (ETDEWEB)

    Gato, L.M.C.; Falcao, Antonio de F.O. [Dept. de Engenharia Mecanica do IST, Lisboa (Portugal); Paulo Alexandre Justino [INETI/DER, Lisboa (Portugal)

    2005-07-01

    The paper reports the optimization study of the electro-mechanical power take-off equipment for the OWC plant whose structure is a caisson forming the head of the new Douro breakwater. The stochastic approach is employed to model the wave-to-wire energy conversion. The optimization includes rotational speed (for each sea state), turbine geometry and size, and generator rated power. The procedure is implemented into a fully integrated computer code, that yields numerical results for the multi-variable optimization process and for the electrical power output (annual average and for different sea states) with modest computing time (much less than if a time-domain model were used instead). Although focused into a particular real case, the paper is intended to outline a design method that can be applied to a wider class of wave energy converters.

  9. Investigations on the porous media equations and resistance coefficients for coastal structures

    DEFF Research Database (Denmark)

    Jensen, Bjarne; Jacobsen, Niels Gjøl; Christensen, Erik Damgaard

    2014-01-01

    previously found in the literature. Constant values for the resistance coefficients for a broad range of flow conditions were recommended based on the new calibrations. The model was validated for the main physical processes that occur in wave–structure interaction in coastal structures including three...... some shortcomings which were identified. The applied type of porosity models relies on empirical resistance coefficients which often need to be measured or calibrated. Only few examples of calibration for numerical models which are present in the literature often applied the same experimental results......-dimensional wave–structure interaction, run-up, run-down and pressure damping, regular and irregular wave conditions and evaluation of overtopping. Simple two and three dimensional uniform caisson structures and breakwater layouts were investigated. The model was implemented in the open source CFD library Open...

  10. Verification of A Numerical Harbour Wave Model

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A numerical model for wave propagation in a harbour is verified by use of physical models. The extended time-dependent mild slope equation is employed as the governing equation, and the model is solved by use of ADI method containing the relaxation factor. Firstly, the reflection coefficient of waves in front of rubble-mound breakwaters under oblique incident waves is determined through physical model tests, and it is regarded as the basis for simulating partial reflection boundaries of the numerical model. Then model tests on refraction, diffraction and reflection of waves in a harbour are performed to measure wave height distribution. Comparative results between physical and numerical model tests show that the present numerical model can satisfactorily simulate the propagation of regular and irregular waves in a harbour with complex topography and boundary conditions.

  11. The Use of Numerical Modeling in the Planning of Physical Model Tests in a Multidirectional Wave Basin

    DEFF Research Database (Denmark)

    Carci, Enric; Rivero, Francisco J.; Burcharth, Hans Falk;

    2003-01-01

    takes place on the breakwater, and it was finally suggested to complement the numerical analysis with physical model tests in a multidirectional wave basin. Due to the large dimensions of the prototype area, several numerical models were applied to optimize the physical model lay-out (model scale......, boundary conditions, location of wave gauges). All physical model test results were compared with results from a spectral wave propagation model GHOST simulations, showing good agreement on wave amplification in the focusing area behind the shoal. The combination of both numerical and physical modeling...... improved the knowledge on the problem studied. Read More: http://www.worldscientific.com/doi/abs/10.1142/9789812791306_0042?prevSearch=The+Use+of+Numerical+Modeling+in+the+Planning+of+Physical+Model+Tests+in+a+Multidirectional+Wave+Basin&searchHistoryKey=...

  12. Evaluation of wave power by integrating numerical models and measures at the Port of Civitavecchia

    International Nuclear Information System (INIS)

    An assessment of the available wave power at regional and local scale was carried out. Two hot spots of higher wave power level were identified and characterized along the coastline of northern Latium Region, near the 'Torre Valdaliga' power plant and in proximity of Civitavecchia’s breakwater, where the presence of a harbour and an electric power plant allows wave energy exploitation. The evaluation process was implemented through measurements, and numerical model assessment and validation. The integration of wave gauges measurements with numerical simulations made it possible to estimate the wave power on the extended area near shore. A down scaling process allowed to proceed from regional to local scale providing increased resolution thanks to highly detailed bathymetry.

  13. The Application of Load-cell Technique in the Study of Armour Unit Responses to Impact Loads

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Liu, Zhou

    1994-01-01

    The slender, complex types of armour units, such as Tetrapods and Dolosse are widely used for rubble mound breakwaters. Many of the recent failures of such structures were caused by unforeseen early breakage of the units, thus revealing an inbalance between the strength (structural integrity) of ...... on slender armour units can be studied by load-cell technique. Moreover, the paper presents Dolos design diagrams for the prediction of both breakage and hydraulic stability.......) of the units and the hydraulic stability (resistance to displacements) of the armour layers. Breakage is caused by stresses from static, pulsating and impact loads. Impact load generated stresses are difficult to investigate due to non-linear scaling laws. The paper describes a method by which impact loads...

  14. The Application of a Numerical Model to Coastal Surface Water Waves

    Institute of Scientific and Technical Information of China (English)

    ZOU Huazhi; LI Huajun; LIU Xiaodong; LIU Aixia

    2005-01-01

    Based on the Navier-Stokes Equations (NSE), numerical simulation with fine grids is conducted to simulate the coastal surface wave changes, including wave generation, propagation, transformation and interactions between waves and structures. This numerical model has been tested for the generation of the desired incident waves, including both regular and random waves. Some numerical results of this model are compared with available experimental data. In order to apply this model to actual cases, boundary conditions are considered in detail for different shoreline types (beach or breakwater, slope or vertical wall, etc. ). Finally, the utility of the model to a real coastal area is shown by applying it to a fishing port located in Shidao, Rongcheng, Shandong Province, P.R. China.

  15. Violent breaking wave impacts

    DEFF Research Database (Denmark)

    Bredmose, Henrik; Peregrine, D.H.; Bullock, G.N.

    2009-01-01

    When an ocean wave breaks against a steep-fronted breakwater, sea wall or a similar marine structure, its impact on the structure can be very violent. This paper describes the theoretical studies that, together with field and laboratory investigations, have been carried out in order to gain...... a better understanding of the processes involved. The wave's approach towards a structure is modelled with classical irrotational flow to obtain the different types of impact profiles that may or may not lead to air entrapment. The subsequent impact is modelled with a novel compressible-flow model...... for a homogeneous mixture of incompressible liquid and ideal gas. This enables a numerical description of both trapped air pockets and the propagation of pressure shock waves through the aerated water. An exact Riemann solver is developed to permit a finite-volume solution to the flow model with smallest possible...

  16. Multiscale Simulation of Breaking Wave Impacts

    DEFF Research Database (Denmark)

    Lindberg, Ole

    errors in the fluid volume. The dam break test case shows that the incompressible and inviscid ALE-WLS model can calculate nonlinear fluid motion, fluid structure impacts and overturning waves. The propagation speed of the wetting front and impact pressures are compared to experiments and the results......The purpose of this project is to make an accurate, robust, geometric flexible and efficient model for calculation of forces on structures from nonlinear ocean waves and breaking wave impacts. Accurate prediction of the extreme forces on wind turbine foundations, breakwaters and tidal or wave power......-distance based adaptivity method and redistributed via a point position filtering method. The incompressible and inviscid ALE-WLS model is applied to the following standard validation test cases: deforming elliptical drop, small amplitude standing waves and the dam break problem. The deforming elliptical drop...

  17. Automatic design system for a steel sheet pile cellular cofferdam and its evaluation; Koya ita cell shiki kozobutsu no kihon sekkei no jidoka oyobi system no hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Sekine, Y.; Ito, A.; Yokota, H. [Port and Harbour Research Inst., Kanagawa (Japan)

    1995-03-01

    A new design scheme has recently been introduced to a sheet pile cellular cofferdam, which takes the effect of the embedded part of a sheet pile on the structural stability into account. On the basis of the modification of the design way, the automatic design system for this type of structure has been established. Port engineers are able to conduct basic design of a breakwater and a seaward made of the sheet pile cellular cofferdam. Parametric studies have been conducted using this automatic design system. It has been confirmed based on the study that this system provides the reasonable structural sections, embedded length, and so on. Some particular characteristics of this type of structures have also been provided in this present report. 5 refs., 59 figs., 4 tabs.

  18. The SSG Wave Energy Converter

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Margheritini, Lucia; Kofoed, Jens Peter;

    2012-01-01

    The Sea-wave Slot-cone Generator concept (SSG) is a Wave Energy Converter based on the wave overtopping principle utilizing several reservoirs placed on top of each other, in which the energy of the incoming wave will be stored as potential energy. The water captured in the reservoirs will then run...... through turbines for electricity production. The system utilizes a wide spectrum of different wave conditions by means of multiple reservoirs, located at different levels above the still water level. Thereby, it obtains a high overall efficiency and it can be suitable for shoreline and breakwater...... applications, presenting particular advantages such as: sharing structure costs, availability of grid connection and infrastructures, recirculation of water inside the harbor, as the outlet of the turbines is on the rear part of the system. Recently, plans for the SSG pilot installation were in progress...

  19. Perangkat Lunak Untuk Analisis Gaya Gelombang Di Laboratorium Lingkungan Dan Energi Laut, Jurusan Teknik Kelautan, Ftk-Its

    Directory of Open Access Journals (Sweden)

    Fendi Hidayat

    2013-09-01

    Full Text Available Laboratorium Lingkungan dan Energi Laut, Jurusan Teknik Kelautan, FTK-ITS sering digunakan untuk pengujian. Salah satunya menguji gaya mooring pada floating breakwater. Hal tersebut menjadi salah satu alasan untuk membuat suatu perangkat lunak dalam membantu dalam proses analisis gaya mooring tersebut. Perangkat lunak yang dibuat berfungsi untuk membantu proses kalibrasi sensor load cell LUB-B 5 to 50 KB dan melakukan analisis gaya gelombang. Metode yang digunakan dalam penelitian ini adalah dengan menggunakan regresi linier, korelasi linier, perhitungan varian, standar deviasi, dan hukum Newton yang kemudian disusun dengan menggunakan Microsoft Visual Studio 2008. Penyusunan perangkat lunak yang bernama FORYS ini memiliki tampilan antarmuka pengguna yang mudah dalam pemakaian. Perangkat lunak yang telah dibuat juga bersifat portable sehingga bisa digunakan di berbagai komputer atau laptop. Hasil pengujian yang telah dilakukan menghasilkan bahwa semakin besar gaya gelombang yang terjadi, maka semakin besar pula tegangan yang terjadi pada tali.  

  20. Vertical 2D Modeling of Free Surface Flow with Hydrodynamic Pressure Using SIMPLE Arithmetic in σ Coordinates

    Institute of Scientific and Technical Information of China (English)

    吴修广; 沈永明; 郑永红

    2004-01-01

    A numerical model for shallow water flow has been developed based on the unsteady Reynolds-averaged NavierStokes equations with the hydrodynamic pressure instead of hydrostatic pressure assumption. The equations are transformed into the σ-coordinate system and the eddy viscosity is calculated with the standard k - e turbulence model. The control volume method is used to discrete the equations, and the boundary conditions at the bed for shallow water models only include vertical diffusion terms expressed with wall functions. And the semi-implicit method for pressure linked equation arithmetic is adopted to solve the equations. The model is applied to the 2D vertical plane flow of a curent over two steep-sided trenches for which experiment data are available for comparison and good agreement is obtained. And the model is used to predicting the flow in a channel with a steep-sided submerged breakwater at the bottom, and the streamline is drawn.

  1. Investigations on the porous resistance coefficients for fishing net structures

    DEFF Research Database (Denmark)

    Chen, Hao; Christensen, Erik Damgaard

    2016-01-01

    The porous media model has been successfully applied to numerical simulation of current and wave interaction with traditional permeable coastal structures such as breakwaters. Recently this model was employed to simulate flow through and around fishing net structures, where the unknown porous...... on a net panel from Morison type load model should be equal to the forces obtained from the porous media model. In order to account for the interaction effects in-between the twines, two coefficients were introduced, and they were calibrated by minimizing the least square error function. Extensive...... validation cases were carried out to examine the performance of the numerical model. This includes steady current flow through plane net panels and circular fish cages, and wave interaction with plane net panels. A variety of fishing nets with different solidity ratios were used in the validation cases, from...

  2. Porous models for wave-seabed interactions

    Energy Technology Data Exchange (ETDEWEB)

    Jeng, Dong-Sheng [Shanghai Jiaotong Univ., SH (China)

    2013-02-01

    Detailed discussion about the phenomenon of wave-seabed interactions. Novel models for wave-induced seabed response. Intensive theoretical derivations for wave-seabed interactions. Practical examples for engineering applications. ''Porous Models for Wave-seabed Interactions'' discusses the Phenomenon of wave-seabed interactions, which is a vital issue for coastal and geotechnical engineers involved in the design of foundations for marine structures such as pipelines, breakwaters, platforms, etc. The most important sections of this book will be the fully detailed theoretical models of wave-seabed interaction problem, which are particularly useful for postgraduate students and junior researchers entering the discipline of marine geotechnics and offshore engineering. This book also converts the research outcomes of theoretical studies to engineering applications that will provide front-line engineers with practical and effective tools in the assessment of seabed instability in engineering design.

  3. Beach nourishment alternative assessment to constrain cross-shore and longshore sediment transport

    Science.gov (United States)

    Karasu, Servet; Work, Paul; Uzlu, Ergun; Kankal, Murat; Yuksek, Omer

    2016-01-01

    A combined field and laboratory investigation was conducted to assess five options for creation of a recreational beach on a steep, armored shoreline on the eastern Black Sea coast. All designs incorporated a beach nourishment project placed between two existing, shore-normal, rubble-mound groins. Alternatives included the placement of a nearshore berm, longshore extensions added to the existing groins, and shore-parallel breakwaters. Several alternatives are reviewed for quantifying the performance of each design, including assessment of the change in shoreline position and project volume retained between the groins. Dimensionless benefits and benefit-cost ratios are quantified, and recommendations made on how to select the best outcome from a benefit-to-cost standpoint when options including hard structures are incorporated into a beach nourishment project design.

  4. Structural Integrity and Hydraulic Stability of Dolos Armour Layers

    DEFF Research Database (Denmark)

    Burcharth, H. F.

    A method for development of design diagrams to ensure structural integrity of slender unreinforced concrete breakwater armour units is presented. The method is based on experimental data from small scale flume tests as well as impact loading of prototype and small scale units. A prerequisite...... for this is the development of a method for full scale impact testing of prototype units. The method which produces repeatable results is applicable also for quality assessment of the concrete, and is widely used today. The theoretical background for the work is the separation of the loads and related stresses into three...... classes: static, pulsating and impact. In principle each type is described independently, and separately scaled by appropriate scaling laws to prototype sizes. The complex stress field is characterized by the maximum principal tensile stress acting in defined critical sections. This one...

  5. Geoarchaeology and geomorphology of Phoenicus ancient harbor, NW coast of Egypt

    Science.gov (United States)

    Moustafa, Samah; Torab, Magdy

    2016-04-01

    Phoenicus Greek harbor located in SE coastline of Ras El Hekma area, west of Alexandria city for about 220 km. It is shaped as triangle with its headland extending into the Mediterranean Sea for about 15 km. It is occupied by sedimentary rocks belonging to the Tertiary and Quaternary Eras, the western coastline consists of Pleistocene, Separated polygons of limestone sheets and fossil lime stone, where there are coastal platforms, fluvial forms and solution holes. The location and description of Phoenicus ancient harbor were mentioned by some late writers (Fourtau,1893) & (Muller,1901), some geoarchaeological indicators were discovered by the authors such as fish tanks, well, remains of breakwater and wine press. The present work is mainly devoted to define the geomorphological and geoarchaelological indicators of Phoenicus Greek harbor site, based on detailed geomorphological and geoarchaelogical surveying, sampling, dating and mapping as well as satellite image interpretation and GIS techniques.

  6. Numerical Simulation of Wave-Induced Currents Combined with Parabolic Mild-Slope Equation in Curvilinear Coordinates

    Institute of Scientific and Technical Information of China (English)

    CUI Lei; TONG Fei-fei; SHI Feng

    2011-01-01

    Researches on breaking-induced currents by waves are summarized firstly in this paper.Then,a combined numerical model in orthogonal curvilinear coordinates is presented to simulate wave-induced current in areas with curved boundary or irregular coastline.The proposed wave-induced current model includes a nearshore current module established through orthogonal curvilinear transformation form of shallow water equations and a wave module based on the curvilinear parabolic approximation wave equation.The wave module actually serves as the driving force to provide the current module with required radiation stresses.The Crank-Nicolson finite difference scheme and the alternating directions implicit method are used to solve the wave and current module,respectively.The established surf zone currents model is validated by two numerical experiments about longshore currents and rip currents in basins with rip channel and breakwater.The numerical results are compared with the measured data and published numerical results.

  7. Draft environmental statement related to the proposed manufacture of floating nuclear power plants (Docket No. STN 50-437)

    International Nuclear Information System (INIS)

    The proposed action is the issuance of a manufacturing license to Offshore Power Systems for the startup and operation of a proposed manufacturing facility located at Blount Island, Jacksonville, Florida (Docket No. STN 50-436). No nuclear fuel will be handled or stored at the manufacturing site. The plants will be fueled after they have been towed to and moored within breadwaters at specific offshore locations designated by the purchaser and after an operating license has been issued by the Nuclear Regulatory Commision. Each nuclear generating plant, mounted on a floating platform, has a net capacity of 1150 MWe. This energy is provided by a pressurized water reactor steam supply system consisting of a Westinghouse four-loop 3425 MWt unit with an ice-condenser containment system. When one or more of these units is located within a single breakwater, the installation is designated an offshore power station. 3 figs., 1 tab

  8. Examination of residence time and its relevance to water quality within a coastal mega-structure: The Palm Jumeirah Lagoon

    Science.gov (United States)

    Cavalcante, Geórgenes H.; Kjerfve, Björn; Feary, David A.

    2012-10-01

    SummaryA numerical modeling study was carried out to compute average residence time in the semi-enclosed lagoon formed by the man-made island Palm Jumeirah (Dubai, United Arab Emirates), termed Palm Jumeirah Lagoon (PJL). The PJL encompasses a main island axis with 17 'fronds' radiating from this axis, all encapsulated within a semi-circular breakwater system. A coupled hydrodynamic and solute transport model was developed for the waters of the PJL, based on depth-integrated conservation equations. Numerical model predictions were then verified against a set of field-measured hydrodynamic data. Model-predicted water elevations and velocities were in good agreement with field measurements. Residence times for this tidal dominated system were investigated through numerical experiments using a conservative tracer as a surrogate. The results indicated that average residence time varied spatially throughout the PJL depending on tidal flushing. Average residence time was unequally distributed throughout the PJL, with the eastern side showing higher flushing times than the western side. In addition, there were also differences between sections of the PJL in average residence time of a tracer: between frond tips and the surrounding breakwater the tracer was reduced to 30-40% of its original value after approximately 1 week, while a tracer placed between the fronds was reduced to 30-40% of its value after 20 days. The findings of this research provide vital information for understanding the water transport process in this man-made lagoon, and will be important in assessing the potential impact on coastal water quality conditions in coastal developments within the Middle East.

  9. On the profile evolution of three artificial pebble beaches at Marina di Pisa, Italy

    Science.gov (United States)

    Bertoni, Duccio; Sarti, Giovanni

    2011-07-01

    In this paper, the profiles of three artificial coarse-grained beaches located at Marina di Pisa (Tuscany, Italy) were monitored from April 2008 to May 2009 in order to define the response of the beaches to major storms that occurred during the study. Two beaches are similar, the third differs in length and in the level of protection, being less than half the length of the others and devoid of an offshore submerged breakwater. The work was achieved by means of accurate topographic surveys intended to reconstruct the beach profile from the backshore up to the foreshore-upper shoreface transition (step). The surveys were performed with an RTK-GPS instrument, which provided extremely precise recording of the beach. The most significant features of the beaches were tracked during each survey; in particular, the landward foot of the storm berm, the crest of the storm berm, the coastline, and the step crest were monitored. Five cross-shore transects were traced on each beach. Along these transects, any meaningful slope change was recorded to obtain accurate sections of the beach. The field datasets were processed with AutoCAD software to compare the beach profile evolution during the year-long research. The results showed a comparable evolution of the twin beaches: the resulting storm berm retreat of about 15 to 19 m is a remarkable feature considering the coarse grain size and the offshore protection. Due to the absence of the breakwater, the third beach was characterized by even higher values of recession (over 20 m), and showed hints of wave reflection-related processes after the huge, steep storm berm had been formed and grown after the high energy events. These processes were not as evident on the twin beaches. These results underline the different response of three similar protection schemes, and the importance that frequent monitoring of the beach morphology holds when it comes to coastal management issues.

  10. Hauling techniques of bucket- based structure%桶式结构运输出运工艺

    Institute of Scientific and Technical Information of China (English)

    秦丹; 黄鹏举; 刘晓曦

    2016-01-01

    连云港港徐圩港区直立堤工程采用的新型无底桶式结构具有施工效率高、造价低、对环境影响小、占有资源少、结构新颖等特点,能适应日益外海化深水化的防波堤工程施工。文章介绍了新型无底桶式结构从预制场地到海上安装位置的运输出运工艺,对场内台车运输工艺、上驳气囊运输工艺、水上气浮拖运工艺等多项关键施工技术进行阐述,可为同类型无底桶式结构项目施工提供参考和借鉴。%The new type of bottomless bucket-based structure is the trend to accommodate the increasing breakwater construction in deep waters and open seas with its numerous advantages: high efficiency, low cost, environment friendly, resource saving and frame novel. It has been applied in the up-right breakwater in Xuwei District in Lianyungang Port. We introduced the hauling techniques of bucket-based structure between the prefabricate site and installation position, described the trolleys, gasbags and pneumatic floating techniques, which can provide reference for the construction of similar bottomless bucket-based structures.

  11. A Molecular Tetrapod for Organic Photovoltaics.

    Science.gov (United States)

    Yang, Jianzhong; Zhang, Zhen; Qin, Yang

    2016-08-31

    The synthesis and characterization of a molecular tetrapod, SFBTD, featuring a tetraphenylsilane center and four identical conjugated arms, which structurally resembles breakwaters in common wave-reducing shore constructions, are reported. Cyclic voltammetry reveals that SFBTD has a medium band gap of ca. 2.0 eV and a low-lying HOMO energy level at ca. -5.2 eV. Absorption spectroscopy, X-ray diffraction, and differential scanning calorimetry experiments reveal a low degree of crystallinity in this compound and slow crystallization kinetics. Bulk heterojunction organic photovoltaics (OPVs) employing SFBTD and fullerene derivatives exhibit power conversion efficiencies (PCEs) up to 1.05% and open-circuit voltage (VOC) values as high as 1.02 V. To the best of our knowledge, this is the highest PCE obtained for OPVs employing molecular tetrapods as donor materials. These devices are relatively thermally stable due to the known ability of breakwater tetrapods to interlock, preventing dislodging and sliding. The lack of favorable phase separations and low hole mobilities of the blend films are the major factors limiting the device performance. Ternary blend devices by the addition of three low band gap poly(thienylene vinylene) (PTV) derivatives were fabricated and tested. We found that the added PTVs acted to be either the major hole conductor or a competing hole conduction channel depending on the HOMO level positions relative to that of SFBTD. Some of the ternary OPV devices out-performed the corresponding binary counterparts employing SFBTD or PTVs alone, suggesting cooperative effects in the ternary systems. PMID:27514435

  12. A Molecular Tetrapod for Organic Photovoltaics.

    Science.gov (United States)

    Yang, Jianzhong; Zhang, Zhen; Qin, Yang

    2016-08-31

    The synthesis and characterization of a molecular tetrapod, SFBTD, featuring a tetraphenylsilane center and four identical conjugated arms, which structurally resembles breakwaters in common wave-reducing shore constructions, are reported. Cyclic voltammetry reveals that SFBTD has a medium band gap of ca. 2.0 eV and a low-lying HOMO energy level at ca. -5.2 eV. Absorption spectroscopy, X-ray diffraction, and differential scanning calorimetry experiments reveal a low degree of crystallinity in this compound and slow crystallization kinetics. Bulk heterojunction organic photovoltaics (OPVs) employing SFBTD and fullerene derivatives exhibit power conversion efficiencies (PCEs) up to 1.05% and open-circuit voltage (VOC) values as high as 1.02 V. To the best of our knowledge, this is the highest PCE obtained for OPVs employing molecular tetrapods as donor materials. These devices are relatively thermally stable due to the known ability of breakwater tetrapods to interlock, preventing dislodging and sliding. The lack of favorable phase separations and low hole mobilities of the blend films are the major factors limiting the device performance. Ternary blend devices by the addition of three low band gap poly(thienylene vinylene) (PTV) derivatives were fabricated and tested. We found that the added PTVs acted to be either the major hole conductor or a competing hole conduction channel depending on the HOMO level positions relative to that of SFBTD. Some of the ternary OPV devices out-performed the corresponding binary counterparts employing SFBTD or PTVs alone, suggesting cooperative effects in the ternary systems.

  13. Public perception of risk and its consequences: the case of a natural fibrous mineral deposit.

    Science.gov (United States)

    Major, G; Vardy, G F

    1989-01-01

    A public authority building a breakwater and other harbour facilities at a small seaport (population 3000) had short-term requirements for 261,000 tonnes of rock and ultimately for 1,000,000 tonnes. A suitable quarry was found about 11 km from the port but unfortunately the rock was found to be contaminated to a small extent with a fibrous mineral identified with the analytical transmission electron microscope as a non-commercial type of fine amphibole with many long fibres. Quarrying only was intended and there were no plans to crush the rock, but the projected work soon brought complaints from local residents, who expressed fears concerning risks to health from what soon became known as 'the asbestos mine'. These complaints posed a dilemma for both the construction and health authorities; they were forcefully expressed, and residents were supported by local newspapers, municipal authorities and regional politicians. The Land and Environment Court ordered (by consent) that the construction authority 'take all reasonable measures to ensure that no loose asbestos material and no rock with any asbestos material exposed on the surface (is) removed from the site'. Personal monitoring of quarry workmen by the membrane filter method and ambient air monitoring near residents' homes with analysis by electron microscope showed that only insignificant concentrations of airborne fibres were present. The breakwater was ultimately completed after much delay and extra expense. Other and greater risks to health and safety, such as the transport of liquid chlorine through the centre of the town to the fish processing plant and the storage, distribution and transport of petroleum products from the nearby regional facilities, were not perceived as such by the residents. PMID:2744844

  14. 地基与海洋建筑物相互作用——以最近西班牙海岸线建筑物内部损坏为例%GROUND-MARITIME STRUCTURE INTERACTION.RECENT FAILURES IN INNER GRAVITY CONSTRUCTIONS ON THE SPANISH COASTLINE

    Institute of Scientific and Technical Information of China (English)

    Carlos Delgado; Dr Civil Engineer.; Professor M.P.U.

    2011-01-01

    海洋工程通常是一个细长的线.我们通常看到的仅仅是建筑物狭长的表面,而不分析支撑他们的大量水下材料.毋庸置疑,海底地基将承受来自于海洋的周期性和交替的静力以及变化的动力.外部和内部的海上工程均在复杂的环境中运行.固态颗粒(防波堤)可以吸入入射水流,并且通过颗粒之间的间距吸收海浪的能量.回流试图从固态颗粒中抽离物质,这样一个遵从太沙基原理的基于有效拉力和中性拉力之间的平衡建立起来.在某些情况下,防护层的液化已经造成了防波堤崩溃(Sines,葡萄牙,1978年2月).在其他情况下,虹吸作用或液化导致巨石(垂直的防波堤)毁坏或崩溃(新巴塞罗那港口,西班牙,2001年11月).结合复合设计工具的地基-作用力--结构相互作用的过程是一个复杂的分析,关于其研究刚刚开始.本文介绍了最近发生在西班牙的、由于地基失效导致的海上工程内部损坏的两个例子(马拉加,2004年7月,巴塞罗那,2007年1月),分析了其成因.%A maritime construction is usually a slender line in the ocean. It is usual to see just its narrow surface strip and not analyse the large amount of submerged material the latter is supporting. Without doubt,it is the ground to which a notable load is transmitted in an environment subjected to periodic, alternating stresses, dynamic forces which the sea's media constitute.Both an outer and inner maritime construction works in a complex fashion. A granular solid(breakwater) breathes with the incident wave flow,dissipating part of the wave energy between its gaps. The backflow tries to extract the different items from the solid block,setting a balance between effective and neutral tensions that follow Terzaghui's principle.On some occasions,fluidification of the armour layer has caused the breakwater to collapse( Sines,Portugal,February 1978 ). On others,siphoning or liquefaction of sand supporting

  15. Environmental policy in the north-eastern sector of the Black sea coast

    Science.gov (United States)

    Kosyan, Ruben; Godin, Evgenii; Kosyan, Alisa

    2015-04-01

    becomes crucial. For a long period of time the coast protective activity was concentrated on elimination of localized zones of washout, without consideration of lithodynamic system in which the protected area is located, that led to disturbance of sediments flows, and, consequently, to acceleration of abrasion on the related parts of the shore. Main technical solutions regarding coast protection constructions for creation of artificial beaches, are borrowed from the experience of coast protection (construction of bunas, breakwaters and wave walls) at Caucasus and Crimean shores of the Black Sea. Application of bunas and breakwaters is formally divided by the steepness of the underwater slope equal to 0.03. However, this division did not and does not have any physical grounds and is not confirmed by materials of study of surf zone's hydro- and lithodynamics. Types of constructions and their composition in the coastal protective complexes were assigned subjectively. Because of general deficit of the sediments, the free beaches with big length were difficult to create. It was neces- sary to build the sediment retaining constructions like bunas, on the landslide sections - underwater breakwaters. Thus, the beaches in the coast protective complexes were having a primary role, and the constructions - secondary.

  16. High Resolution Tsunami Modeling and Assessment of Harbor Resilience; Case Study in Istanbul

    Science.gov (United States)

    Cevdet Yalciner, Ahmet; Aytore, Betul; Gokhan Guler, Hasan; Kanoglu, Utku; Duzgun, Sebnem; Zaytsev, Andrey; Arikawa, Taro; Tomita, Takashi; Ozer Sozdinler, Ceren; Necmioglu, Ocal; Meral Ozel, Nurcan

    2014-05-01

    Ports and harbors are the major vulnerable coastal structures under tsunami attack. Resilient harbors against tsunami impacts are essential for proper, efficient and successful rescue operations and reduction of the loss of life and property by tsunami disasters. There are several critical coastal structures as such in the Marmara Sea. Haydarpasa and Yenikapi ports are located in the Marmara Sea coast of Istanbul. These two ports are selected as the sites of numerical experiments to test their resilience under tsunami impact. Cargo, container and ro-ro handlings, and short/long distance passenger transfers are the common services in both ports. Haydarpasa port has two breakwaters with the length of three kilometers in total. Yenikapi port has one kilometer long breakwater. The accurate resilience analysis needs high resolution tsunami modeling and careful assessment of the site. Therefore, building data with accurate coordinates of their foot prints and elevations are obtained. The high resolution bathymetry and topography database with less than 5m grid size is developed for modeling. The metadata of the several types of structures and infrastructure of the ports and environs are processed. Different resistances for the structures/buildings/infrastructures are controlled by assigning different friction coefficients in a friction matrix. Two different tsunami conditions - high expected and moderate expected - are selected for numerical modeling. The hybrid tsunami simulation and visualization codes NAMI DANCE, STOC-CADMAS System are utilized to solve all necessary tsunami parameters and obtain the spatial and temporal distributions of flow depth, current velocity, inundation distance and maximum water level in the study domain. Finally, the computed critical values of tsunami parameters are evaluated and structural performance of the port components are discussed in regard to a better resilience. ACKNOWLEDGEMENTS: Support by EU 603839 ASTARTE Project, UDAP-Ç-12

  17. Archaeogeophysical Studies in Ancient Tios, Zonguldak-Caycuma-Filyos, Turkey

    Science.gov (United States)

    Ahmet Yuksel, Fethi; Hoskan, Nihan; Sumer Atasoy, Yusuf

    2010-05-01

    Ancient Tios is located in the Filyos township of the Caycuma District of Zonguldak on the western Black Sea region, Turkey. The ancient city was probably founded by Milesians in the 7th cent. B.C. The region was inhabited through the centuries by Persians, Romans, Genoese and all the way to the Ottoman times. About the archaeological history of the city , we have relatively limited knowledge both in ancient records and in contemporary archaeological research. In the Roman period coastal defensive walls, acquaduct, theatre, defensive tower and the port with its breakwater are the only visible remains of the city. The acropolis of the ancient city is located immediately to the east of the present Filyos township on a hill. The original architectural form of the defensive wall located in the acropolis will be revealed after research to its foundation completed. A partially destroyed stone building is another remaining ruin in the acropolis .The Roman period theatre of Tios is located in the north of the road leading into Filyos. Built on a sloping land, local stones were used in its construction. Mostly ruined its original stones have been used later in other buildings. Only a few of the arches of the aquaduct, located to the north of the theatre, are still standing. There are the remains of another structure which could have been a defensive tower located in 200 meters to the west of the theatre. GPR measurements display the exact location of any sub-surface structures. To the west of the acropolis and within the ancient port, there are the under water remains of a breakwater. The local sandstones, quarries were studied archaeogeologically as they provided the main building materials. Since there has been no archaeological research done on the site until the 2006 season, archaeogeopysical data are reveal additional information about ancient Tios. Surface survey and georadar, magnetic and geoelectric studies have been done and after that, excavations were started

  18. HySEA model verification for Tohoku 2011 Tsunami. Application for mitigation tsunami assessment

    Science.gov (United States)

    Macias, Jorge; González-Vida, José Manuel; García, Javier; Castro, Manuel; Ortega, Sergio; de la Asunción, Marc

    2015-04-01

    In many aspects Tohoku-Oki 2011 mega tsunami has changed our perception of tsunami risk. The tsunami-HySEA model is used to numerically simulate this event and observed data will we used to verify the model results. Three nested meshes of enhanced resolution (4 arc-min, 32 arc-sec and 2 arc-sec) will be used by the numerical model. The propagation mesh covers all Pacific Ocean with more of 7 million cells. An intermediate mesh with 5 millions cells contains the Japanese archipelago and, finally, two finer meshes, with nearly 8 and 6 millions cells, cover Iwate and Miyagi Prefectures at Tohoku region, the most devastated areas hit by the tsunami. The presentation will focus on the impact of the tsunami wave in these two areas and comparisons with observed data will be performed. DART buoys time series, inundation area and observed runup is used to assess model performance. The arrival time of the leading flooding wave at the vicinity of the Senday airport, as recorded by video cameras, is also used as verification data for the model. After this tsunami, control forests as well as breakwaters has been discussed as suitable mitigation infrastructures. As particular case, we will analyse the evolution of the tsunami in the area around the Sendai airport (Miyagi Prefecture) and its impact on the airport. A second simulation has been performed, assuming the existence of a coastal barrier protecting the area. The role of this barrier in modifying tsunami wave evolution and mitigating flooding effects on the airport area are discussed. The protection effect of the breakwaters near Kamaishi (Iwate Prefecture) is also assessed. The numerical model shows how these structures, although did not provide a full protection to tsunami waves, they helped to largely mitigate its effects in the area. Acknowledgements. This research has been partially supported by the Junta de Andalucía research project TESELA (P11-RNM7069), the Spanish Government Research project DAIFLUID (MTM2012

  19. An innovative early warning system for floods and operational risks in harbours

    Science.gov (United States)

    Smets, Steven; Bolle, Annelies; Mollaert, Justine; Buitrago, Saul; Gruwez, Vincent

    2016-04-01

    Early Warning Systems (EWS) are nowadays becoming fairly standard in river flood forecasting or in large scale hydrometeorological predictions. For complex coastal morphodynamic problems or in the vicinity of complex coastal structures, such as harbours, EWS are much less used because they are both technically and computationally still very challenging. To advance beyond the state-of-the-art, the EU FP7 project Risc-KIT (www.risc-kit.eu) is developing prototype EWS which address specifically these topics. This paper describes the prototype EWS which IMDC has developed for the case study site of the harbour of Zeebrugge. The harbour of Zeebrugge is the largest industrial seaport on the coast of Belgium, extending more than 3 km into the sea. Two long breakwaters provide shelter for the inner quays and docks for regular conditions and frequent storms. Extreme storms surges and waves can however still enter the harbour and create risks for the harbour operations and infrastructure. The prediction of the effects of storm surges and waves inside harbours are typically very complex and challenging, due to the need of different types of numerical models for representing all different physical processes. In general, waves inside harbours are a combination of locally wind generated waves and offshore wave penetration at the port entrance. During extreme conditions, the waves could overtop the quays and breakwaters and flood the port facilities. Outside a prediction environment, the conditions inside the harbour could be assessed by superimposing processes. The assessment can be carried out by using a combination of a spectral wave model (i.e. SWAN) for the wind generated waves and a Boussinesq type wave model (i.e. Mike 21 BW) for the wave penetration from offshore. Finally, a 2D hydrodynamic model (i.e. TELEMAC) can be used to simulate the overland flooding inside the port facilities. To reproduce these processes in an EWS environment, an additional challenge is to cope

  20. Construction and start-up testing experience of Kashiwazakikariwa Nuclear Power Station Unit No.1

    International Nuclear Information System (INIS)

    In order to overcome the new location condition in Japan Sea coast, new techniques were developed and adopted to ensure the safety in construction and to shorten the construction period as far as possible. The commercial operation was started on September 18, 1985. This plant is a BWR plant of 1100 MWe output. The results of the improvement and standardization of BWRs and the measures for reliability improvement and radiation dose reduction were fully adopted in this plant. The site of the power station and the layout of the main facilities are explained. As the features of the location condition, the severe weather condition in winter such as snow, wind and lightning and high waves in the sea were considered. The rockbed for installing the foundation of the reactor building was deep, and the aseismatic design condition was made stricter, accordingly, the quantity of materials increased. A tent dome was developed to cover above the reactor containment vessel being assembled, a lightning forecast system was installed, and synchro-lift method was adopted for caisson breakwaters. The countermeasures to the deep rockbed and the measures to shorten the construction period were taken. The results of the trial operation are reported. (Kako, I.)

  1. Wave Damping and Refraction-Diffraction Due to Variable Depth Porous Bottom

    Institute of Scientific and Technical Information of China (English)

    朱书堂

    2004-01-01

    The refraction-diffraction of surface waves due to porous variable depth has been the subject of many investigations. In the present study, we extend the boundary-value problem of impermeable varying topography to that of a variable depth porous seabed, which is the situation most likely to be encountered in practical problems of coastal engineering. A wave-induced fluid motion is applied to the porous bottom, while the well-known linear potential theory is applied to the free-water above the bottom. Eigenfunction expansions are employed to derive the matching condition and the so-called modified dispersion relation. As a result of the porous bottom, the wavenumber becomes a complex value, of which the real part represents the spatial periodicity while the imaginary part refers to the energy dissipation. The characteristics of water waves over a porous bottom are studied in detail. By neglecting the non-propagating modes which only have a local effect and damp exponentially with distance, we derive a mathematical model to represent the characteristics of both the wave refraction-diffraction and wave-damping. The developed model is applied to the damping problem of waves over submerged porous breakwaters.

  2. Possibilities of the particle finite element method for fluid-soil-structure interaction problems

    Science.gov (United States)

    Oñate, Eugenio; Celigueta, Miguel Angel; Idelsohn, Sergio R.; Salazar, Fernando; Suárez, Benjamín

    2011-09-01

    We present some developments in the particle finite element method (PFEM) for analysis of complex coupled problems in mechanics involving fluid-soil-structure interaction (FSSI). The PFEM uses an updated Lagrangian description to model the motion of nodes (particles) in both the fluid and the solid domains (the later including soil/rock and structures). A mesh connects the particles (nodes) defining the discretized domain where the governing equations for each of the constituent materials are solved as in the standard FEM. The stabilization for dealing with an incompressibility continuum is introduced via the finite calculus method. An incremental iterative scheme for the solution of the non linear transient coupled FSSI problem is described. The procedure to model frictional contact conditions and material erosion at fluid-solid and solid-solid interfaces is described. We present several examples of application of the PFEM to solve FSSI problems such as the motion of rocks by water streams, the erosion of a river bed adjacent to a bridge foundation, the stability of breakwaters and constructions sea waves and the study of landslides.

  3. Biofouling protection for marine environmental sensors

    Directory of Open Access Journals (Sweden)

    L. Delauney

    2010-05-01

    Full Text Available These days, many marine autonomous environment monitoring networks are set up in the world. These systems take advantage of existing superstructures such as offshore platforms, lightships, piers, breakwaters or are placed on specially designed buoys or underwater oceanographic structures. These systems commonly use various sensors to measure parameters such as dissolved oxygen, turbidity, conductivity, pH or fluorescence. Emphasis has to be put on the long term quality of measurements, yet sensors may face very short-term biofouling effects. Biofouling can disrupt the quality of the measurements, sometimes in less than a week.

    Many techniques to prevent biofouling on instrumentation are listed and studied by researchers and manufacturers. Very few of them are implemented on instruments and of those very few have been tested in situ on oceanographic sensors for deployment of at least one or two months.

    This paper presents a review of techniques used to protect against biofouling of in situ sensors and gives a short list and description of promising techniques.

  4. Predicting coastal morphological changes with empirical orthogonal functionmethod

    Directory of Open Access Journals (Sweden)

    Fernando Alvarez

    2016-01-01

    Full Text Available In order to improve the accuracy of prediction when using the empirical orthogonal function (EOF method, this paper describes a novel approach for two-dimensional (2D EOF analysis based on extrapolating both the spatial and temporal EOF components for long-term prediction of coastal morphological changes. The approach was investigated with data obtained from a process-based numerical model, COAST2D, which was applied to an idealized study site with a group of shore-parallel breakwaters. The progressive behavior of the spatial and temporal EOF components, related to bathymetric changes over a training period, was demonstrated, and EOF components were extrapolated with combined linear and exponential functions for long-term prediction. The extrapolated EOF components were then used to reconstruct bathymetric changes. The comparison of the reconstructed bathymetric changes with the modeled results from the COAST2D model illustrates that the presented approach can be effective for long-term prediction of coastal morphological changes, and extrapolating both the spatial and temporal EOF components yields better results than extrapolating only the temporal EOF component.

  5. Final environmental statement related to the proposed manufacture of floating nuclear power plants by Offshore Power Systems: (Docket No. STN 50-437): Part 2, A generic environmental statement considering the siting and operation of floating nuclear power plants

    International Nuclear Information System (INIS)

    The proposed action is the issuance of a manufacturing license to Offshore Power Systems for the startup and operation of a proposed manufacturing facility located at Blount Island, Jacksonville, Florida (Docket No. STN 50-437). No nuclear fuel will be handled or stored at the manufacturing site. The plants will be fueled after they have been towed to and moored within protected basins at specific locations designated by the purchaser and after an operating license has been issued by the Nuclear Regulatory Commission. Each nuclear generating plant, mounted on a floating platform, has a net capacity of 1150 MWe. This energy is provided by a pressurized water reactor steam supply system consisting of a Westinghouse four-loop 3425-MWt unit with an ice-condenser containment system. When one or more of these units is located within a single breakwater, the installation is designated an offshore power station. Volume 2 contains the siting criteria, regulations, effects of construction, effects of operation, and a safety analysis. 2 figs., 2 tabs

  6. Coastline changes in relation to longshore sediment transport and human impact, along the shoreline of Kato Achaia (NW Peloponnese, Greece

    Directory of Open Access Journals (Sweden)

    S. POULOS

    2012-12-01

    Full Text Available Coastal configuration depends upon the equilibrium between available sediment budget and prevailing nearshore wave and current conditions. Human activities often disturb this natural equilibrium by altering the sources of beach material and littoral drift pattern. In the coastal zone of NW Peloponnese, an essentially tideless environment, the oblique approach of wind-induced waves implies an overall longshore drift from east to west. On an annual basis, the potential longshore sediment transport rates at the different sections of the study area (Kato Achaia is estimated to vary between 0.02 10-3 m3/s and 5 103 m3/s and to fluctuate seasonally. The construction of a port and the extraction of aggregates from the R. Peiros have changed significantly the pattern of sediment transport inducing dramatic changes on coastline configuration; thus, the part of the coastline west to the port had retreated as much as 70 m eliminating a touristic beach, while the entrance of the port was silted inhibiting navigation. Coastal engineering measures, such as modification of port-breakwaters and construction of groins have had only minimal contribution in beach recovery. Hence, coastal management plans should consider this dynamic equilibrium and protect the natural coastal system from the arbitrary human activities.

  7. Applying Uav and Photogrammetry to Monitor the Morphological Changes Along the Beach in Penghu Islands

    Science.gov (United States)

    Lu, Cheng-Hao

    2016-06-01

    Penghu islands, in the southern Taiwan Strait, is a remnant of a middle-late Miocene basaltic shield volcano. We present a procedure to use UAV (Unmanned Aerial Vehicles) to perform photogrammetry survey and monitoring analysis in beach evolution scenarios. The aim of this study is to understand spatial-temporal change along the sandy beach in Penghu islands, especially as for the effects of typhoon and coastal structures. According to the study result, this example of application is provided to show the results and the potential of this methodology in real beach changes. In addition, we found the typhoon and coastal structures play important roles to shape the beach morphology and its evolution. The result of beach monitoring reveals that the reduction and change of sand volume in Shanshui beach resulted from the placement of detached breakwater complexes. This coastal structure likely resulted in the development of tombolo and therefor make the beach unstable and subject to conduct rip current and more erosion.

  8. Resilience from coastal protection.

    Science.gov (United States)

    Ewing, Lesley C

    2015-10-28

    Coastal areas are important residential, commercial and industrial areas; but coastal hazards can pose significant threats to these areas. Shoreline/coastal protection elements, both built structures such as breakwaters, seawalls and revetments, as well as natural features such as beaches, reefs and wetlands, are regular features of a coastal community and are important for community safety and development. These protection structures provide a range of resilience to coastal communities. During and after disasters, they help to minimize damages and support recovery; during non-disaster times, the values from shoreline elements shift from the narrow focus on protection. Most coastal communities have limited land and resources and few can dedicate scarce resources solely for protection. Values from shore protection can and should expand to include environmental, economic and social/cultural values. This paper discusses the key aspects of shoreline protection that influence effective community resilience and protection from disasters. This paper also presents ways that the economic, environmental and social/cultural values of shore protection can be evaluated and quantified. It presents the Coastal Community Hazard Protection Resilience (CCHPR) Index for evaluating the resilience capacity to coastal communities from various protection schemes and demonstrates the use of this Index for an urban beach in San Francisco, CA, USA. PMID:26392613

  9. Analysis of Tsunami Evacuation Issues Using Agent Based Modeling. A Case Study of the 2011 Tohoku Tsunami in Yuriage, Natori.

    Science.gov (United States)

    Mas, E.; Takagi, H.; Adriano, B.; Hayashi, S.; Koshimura, S.

    2014-12-01

    The 2011 Great East Japan earthquake and tsunami reminded that nature can exceed structural countermeasures like seawalls, breakwaters or tsunami gates. In such situations it is a challenging task for people to find nearby haven. This event, as many others before, confirmed the importance of early evacuation, tsunami awareness and the need for developing much more resilient communities with effective evacuation plans. To support reconstruction activities and efforts on developing resilient communities in areas at risk, tsunami evacuation simulation can be applied to tsunami mitigation and evacuation planning. In this study, using the compiled information related to the evacuation behavior at Yuriage in Natori during the 2011 tsunami, we simulated the evacuation process and explored the reasons for the large number of fatalities in the area. It was found that residents did evacuate to nearby shelter areas, however after the tsunami warning was increased some evacuees decided to conduct a second step evacuation to a far inland shelter. Simulation results show the consequences of such decision and the outcomes when a second evacuation would not have been performed. The actual reported number of fatalities in the event and the results from simulation are compared to verify the model. The case study shows the contribution of tsunami evacuation models as tools to be applied for the analysis of evacuees' decisions and the related outcomes. In addition, future evacuation plans and activities for reconstruction process and urban planning can be supported by the results provided from this kind of tsunami evacuation models.

  10. An alternative approach for addressing the failure probability-safety factor method with sensitivity analysis

    Energy Technology Data Exchange (ETDEWEB)

    Castillo, Enrique; Conejo, Antonio J.; Minguez, Roberto; Castillo, Carmen

    2003-11-01

    The paper introduces a method for solving the failure probability-safety factor problem for designing engineering works proposed by Castillo et al. that optimizes an objective function subject to the standard geometric and code constraints, and two more sets of constraints that simultaneously guarantee given safety factors and failure probability bounds associated with a given set of failure modes. The method uses the dual variables and is especially convenient to perform a sensitivity analysis, because sensitivities of the objective function and the reliability indices can be obtained with respect to all data values. To this end, the optimization problems are transformed into other equivalent ones, in which the data parameters are converted into artificial variables, and locked to their actual values. In this way, some variables of the associated dual problems become the desired sensitivities. In addition, using the proposed methodology, calibration of codes based on partial safety factors can be done. The method is illustrated by its application to the design of a simple rubble mound breakwater and a bridge crane.

  11. Nearshore hydrodynamics as loading and forcing factors for Escherichia coli contamination at an embayed beach

    Science.gov (United States)

    Ge, Zhongfu; Whitman, Richard L.; Nevers, Meredith B.; Phanikumar, Mantha S.; Byappanahalli, Muruleedhara N.

    2012-01-01

    Numerical simulations of the transport and fate of Escherichia coli were conducted at Chicago's 63rd Street Beach, an embayed beach that had the highest mean E. coli concentration among 23 similar Lake Michigan beaches during summer months of 2000-2005, in order to find the cause for the high bacterial contamination. The numerical model was based on the transport of E. coli by current circulation patterns in the embayment driven by longshore main currents and the loss of E. coli in the water column, taking settling as well as bacterial dark- and solar-related decay into account. Two E. coli loading scenarios were considered: one from the open boundary north of the embayment and the other from the shallow water near the beachfront. Simulations showed that the embayed beach behaves as a sink for E. coli in that it generally receives E. coli more efficiently than it releases them. This is a result of the significantly different hydrodynamic forcing factors between the inside of the embayment and the main coastal flow outside. The settled E. coli inside the embayment can be a potential source of contamination during subsequent sediment resuspension events, suggesting that deposition-resuspension cycles of E. coli have resulted in excessive bacterial contamination of beach water. A further hypothetical case with a breakwater shortened to half its original length, which was anticipated to enhance the current circulation in the embayment, showed a reduction in E. coli concentrations of nearly 20%.

  12. 3-Dimensional Stochastic Seepage Analysis of a Yangtze River Embankment

    Directory of Open Access Journals (Sweden)

    Yajun Wang

    2015-01-01

    Full Text Available Three-dimensional stochastic simulation was performed to investigate the complexity of the seepage field of an embankment. Three-dimensional anisotropic heterogeneous steady state random seepage finite element model was developed. The material input data were derived from a statistical analysis of strata soil characteristics and geological columns. The Kolmogorov-Smirnov test was used to validate the hypothesis that the Gaussian probability distribution is applicable to the random permeability tensors. A stochastic boundary condition, the random variation of upstream and downstream water level, was taken into account in the three-dimensional finite element modelling. Furthermore, the functions of sheet-pile breakwater and catchwater were also incorporated as turbulent sources. This case, together with the variability of soil permeability, has been analyzed to investigate their influence on the hydraulic potential distributed and the random evolution of stochastic seepage field. Results from stochastic analyses have also been compared against those of deterministic analyses. The insights gained in this study suggest it is necessary, feasible, and practical to employ stochastic studies in seepage field problems. The method provides a more comprehensive stochastic algorithm than conventional ones to characterize and analyze three-dimensional random seepage field problems.

  13. Drivers of Coastal Shoreline Change: Case Study of Hon Dat Coast, Kien Giang, Vietnam

    Science.gov (United States)

    Nguyen, Hai-Hoa; McAlpine, Clive; Pullar, David; Leisz, Stephen Joseph; Galina, Gramotnev

    2015-05-01

    Coastal shorelines are naturally dynamic, shifting in response to coastal geomorphological processes. Globally, land use change associated with coastal urban development and growing human population pressures is accelerating coastal shoreline change. In southern Vietnam, coastal erosion currently is posing considerable risks to shoreline land use and coastal inhabitants. The aim of this paper is to quantify historical shoreline changes along the Hon Dat coast between 1995 and 2009, and to document the relationships between coastal mangrove composition, width and density, and rates of shoreline change. The generalized linear mixed-effects models were used to quantify the major biophysical and land-use factors influencing shoreline change rates. Most significant drivers of the rates of change are cutting of mangroves, the dominant mangrove genus, changes in adjacent shoreline land use, changes of shoreline land cover, and width of fringing mangroves. We suggest that a possible and inexpensive strategy for robust mangrove shoreline defense is direct mangrove planting to promote mangrove density with the presence of breakwater structures. In the shorter term, construction of coastal barriers such as fence-structured melaleuca poles in combination with mangrove restoration schemes could help retain coastal sediments and increase the elevation of the accretion zone, thereby helping to stabilize eroding fringe shorelines. It also is recommended that implementation of a system of payments for mangrove ecosystem services and the stronger regulation of mangrove cutting and unsustainable land-use change to strengthen the effectiveness of mangrove conservation programs and coastal land-use management.

  14. Development of a numerical 2-dimensional beach evolution model

    DEFF Research Database (Denmark)

    Baykal, Cüneyt

    2014-01-01

    This paper presents the description of a 2-dimensional numerical model constructed for the simulation of beach evolution under the action of wind waves only over the arbitrary land and sea topographies around existing coastal structures and formations. The developed beach evolution numerical mode...... groin, and a series of offshore breakwaters. The numerical model gave results in agreement with the measurements both qualitatively and quantitatively and reflected the physical concepts well for the selected conceptual cases.......This paper presents the description of a 2-dimensional numerical model constructed for the simulation of beach evolution under the action of wind waves only over the arbitrary land and sea topographies around existing coastal structures and formations. The developed beach evolution numerical model...... is composed of 4 submodels: a nearshore spectral wave transformation model based on an energy balance equation including random wave breaking and diffraction terms to compute the nearshore wave characteristics, a nearshore wave-induced circulation model based on the nonlinear shallow water equations...

  15. A Coupling Model of Nonlinear Wave and Sandy Seabed Dynamic Interaction

    Institute of Scientific and Technical Information of China (English)

    CHENG Yong-zhou; WANG Yong-xue; JIANG Chang-bo

    2007-01-01

    In the paper,a weak coupling numerical model is developed for the study of the nonlinear dynamic interaction between water waves and permeable sandy seabed.The wave field solver is based on the VOF (Volume of Fluid) method for continuity equation and the two-dimensional Reynolds Averaged Navier Stokes (RANS) equations with a k-ε closure.The free surface of cnoidal wave is traced through the PLIC-VOF (Piecewise Linear Interface Construction).Biot's equations have been applied to solve the sandy seabed,and the u-p finite element formulations are derived by the application of the Galerkin weighted-residual procedure.The continuity of the pressure on the interface between fluid and porous medium domains is considered.Laboratory tests were performed to verify the proposed numerical model,and it is shown that the pore-water pressures and the wave heights computed by the VOF-FEM models are in good agreement with the experimental results.It is found that the proposed model is effective in predicting the seabed-nonlinear wave interaction and is able to handle the wave-breakwater-seabed interaction problem.

  16. Reinforcing method for littoral structures in thermal and nuclear power stations

    International Nuclear Information System (INIS)

    Recently, the thermal and nuclear power stations in Japan are often exposed directly to severe sea condition owing to the situation of their location and construction. In this paper, underwater asphalt construction method (asphalt mats, sand mastic) and hydrocrete construction method (underwater unseparable concrete) are described as the reinforcing method for littoral structures such as breakwaters, protective banks, water intakes and discharge chennels. The asphalt mats are formed in precast state, burying reinforcing core materials such as glass fiber nets or wires in asphalt mastic, the mixture of asphalt, filler and aggregate. The sand mastic is the fluid asphalt compound, in which asphalt, stone dust and sand are heated and mixed, and is poured and solidified into the gaps in rubble mounds in water, to reinforce them. The hydrocrete is the underwater concrete of high quality made by blending special polymer compound to ordinary concrete, which does not separate during free descent in water, and the contamination of water quality is scarce. The features and applications of these construction methods are explained. Also, the examples of actual construction works are shown. (Kako, I.)

  17. Analysis of Short-Term Steel Corrosion Products Formed in Tropical Marine Environments of Panama

    Directory of Open Access Journals (Sweden)

    Juan A. Jaén

    2012-01-01

    Full Text Available A low-carbon steel A-36 and two conventional weathering steels A-588 and COR-420 exposed at four atmospheric test stations located in (i Tocumen, an urban site near the Pacific Ocean, (ii Sherman-Open, (iii Sherman-Coastal, and (iv Sherman-Breakwater on the Caribbean coast of Panama. Kinetics of the short-term atmospheric corrosion process and the relationship with exposure time and environmental characteristics of each site were investigated. The atmospheric exposure conditions, particularly the time of wetness, deposition of chloride, and the washing effect of contaminants on the metal surface by rain are of upmost importance in determining the corrosion behaviour and composition of rust. The corrosion products were mainly identified using room temperature and low temperature (80 K Mössbauer spectroscopy, FTIR, and X-ray powder diffraction. In all samples, γ-FeOOH and α-FeOOH were the main constituents. Maghemite (γ-Fe2O3, magnetite (Fe3O4, and Akaganeite (β-FeOOH were also identified.

  18. Guide to MildSim

    DEFF Research Database (Denmark)

    Christensen, Hanne Rolfdal; Thomassen, Kristina; Kofoed, Jens Peter;

    The changes in the wave conditions when approaching the coast are caused by shoaling, refraction, diffraction, and wave breaking [Andersen and Frigaard, 2008]. All these effects are easiest taken into account by using a numerical program such as MILDSIM which accurately computes the mentioned...... with corrections, the program works with models where the slope of the seabed is up to 1:1. As input in MILDSIM the water depths in the analysed area are needed and the programs ENGAUGE and VANDLAND are therefore described as well, as they set up the distribution of land, water, and water depths. In this paper...... an expansion of Hanstholm Harbour is used as an example. The expansion includes a new breakwater north-east of the existing harbour at a water depth of 7 m. From an extreme wave analysis the significant wave height at a water depth of 20 m is found to Hs = 7.3m and a corresponding peak period Tp = 14.4 s...

  19. Biofouling protection for marine environmental sensors

    Science.gov (United States)

    Delauney, L.; Compère, C.; Lehaitre, M.

    2010-05-01

    These days, many marine autonomous environment monitoring networks are set up in the world. These systems take advantage of existing superstructures such as offshore platforms, lightships, piers, breakwaters or are placed on specially designed buoys or underwater oceanographic structures. These systems commonly use various sensors to measure parameters such as dissolved oxygen, turbidity, conductivity, pH or fluorescence. Emphasis has to be put on the long term quality of measurements, yet sensors may face very short-term biofouling effects. Biofouling can disrupt the quality of the measurements, sometimes in less than a week. Many techniques to prevent biofouling on instrumentation are listed and studied by researchers and manufacturers. Very few of them are implemented on instruments and of those very few have been tested in situ on oceanographic sensors for deployment of at least one or two months. This paper presents a review of techniques used to protect against biofouling of in situ sensors and gives a short list and description of promising techniques.

  20. Long-Term Assessment of an Innovative Mangrove Rehabilitation Project: Case Study on Carey Island, Malaysia

    Directory of Open Access Journals (Sweden)

    Shervin Motamedi

    2014-01-01

    Full Text Available Wave energy and storm surges threaten coastal ecology and nearshore infrastructures. Although coastal structures are conventionally constructed to dampen the wave energy, they introduce tremendous damage to the ecology of the coast. To minimize environmental impact, ecofriendly coastal protection schemes should be introduced. In this paper, we discuss an example of an innovative mangrove rehabilitation attempt to restore the endangered mangroves on Carey Island, Malaysia. A submerged detached breakwater system was constructed to dampen the energy of wave and trap the sediments behind the structure. Further, a large number of mangrove seedlings were planted using different techniques. Further, we assess the possibility of success for a future mangrove rehabilitation project at the site in the context of sedimentology, bathymetry, and hydrogeochemistry. The assessment showed an increase in the amount of silt and clay, and the seabed was noticeably elevated. The nutrient concentration, the pH value, and the salinity index demonstrate that the site is conducive in establishing mangrove seedlings. As a result, we conclude that the site is now ready for attempts to rehabilitate the lost mangrove forest.

  1. Long-term assessment of an innovative mangrove rehabilitation project: case study on Carey Island, Malaysia.

    Science.gov (United States)

    Motamedi, Shervin; Hashim, Roslan; Zakaria, Rozainah; Song, Ki-Il; Sofawi, Bakrin

    2014-01-01

    Wave energy and storm surges threaten coastal ecology and nearshore infrastructures. Although coastal structures are conventionally constructed to dampen the wave energy, they introduce tremendous damage to the ecology of the coast. To minimize environmental impact, ecofriendly coastal protection schemes should be introduced. In this paper, we discuss an example of an innovative mangrove rehabilitation attempt to restore the endangered mangroves on Carey Island, Malaysia. A submerged detached breakwater system was constructed to dampen the energy of wave and trap the sediments behind the structure. Further, a large number of mangrove seedlings were planted using different techniques. Further, we assess the possibility of success for a future mangrove rehabilitation project at the site in the context of sedimentology, bathymetry, and hydrogeochemistry. The assessment showed an increase in the amount of silt and clay, and the seabed was noticeably elevated. The nutrient concentration, the pH value, and the salinity index demonstrate that the site is conducive in establishing mangrove seedlings. As a result, we conclude that the site is now ready for attempts to rehabilitate the lost mangrove forest. PMID:25097894

  2. Conservation status and updated census of Patella ferruginea (Gastropoda, Patellidae in Ceuta: distribution patterns and new evidence of the effects of environmental parameters on population structure

    Directory of Open Access Journals (Sweden)

    Rivera–Ingraham, G. A.

    2011-06-01

    Full Text Available The Strait of Gibraltar has important populations of the highly endangered patellid limpet Patella ferruginea. Between 2006 and 2010, an exhaustive census was carried out in Ceuta. The total coastline was divided into 17 sectors. The coast of each sector was examined by using 10 m transects. For the case of those sectors composed of breakwaters, jetties or islets, no transects were used, and instead, the total number of individuals was recorded. Each individual was measured to the nearest millimetre using a calliper. Moreover, the complete rocky shore length where the species could potentially be present was calculated, and an estimation of the total number of individuals that each sector could host was made. Results indicate that Ceuta could be home to around 44,000 individuals. The species found in Point Benzú, its westernmost limit of distribution on the North African coasts. The largest populations were recorded on the South Bay, with higher Mediterranean influence. Our results indicate that substrate roughness (topographic heterogeneity and the area’s accessibility highly influence the abundance and population structure. Those populations located on high topographic heterogeneity substrates show higher recruitment rates and lower percentages of larger individuals, while medium to low rugosity surfaces presented the opposite pattern. Additionally, easily accessible areas (and frequented by humans presented smaller average shell sizes. Implications of the results for conservation purposes are discussed.

  3. Design and construction of the south bulkhead of Hitachinaka Thermal Power Plant; Hitachinaka Karyoku Hatsudensho minami gogan no sekkei to seko

    Energy Technology Data Exchange (ETDEWEB)

    Kuwabara, S.; Takahashi, Y.; Noguchi, K. [Tokyo Electric Power Co., Inc. (Japan)

    1996-11-05

    Hitachinaka Thermal Power Plant is a coal fired thermal power plant that Tokyo Electric Power Co. and Electric Power Development Corp. have planned to install a machine of an output of 1,000MW each respectively, totalling an output of 2,000MW jointly in the north wharf of Hitachinaka harbor now planned by Ibaraki Prefecture. It is anticipated to be the main power source for the prefecture in the early 21st century. In addition, in the above north wharf area, there are public facilities to be constructed by Ministry of Transport and Ibaraki Prefecture. The construction of the bulkhead of this north wharf has been designed and executed by the above 4 bodies in taking the respective shares and completed in 3 years. In this report, the outline of cost reduction concerning the design and construction of the south bulkhead (total length: 250m) including the intake of the plant is introduced from among the bulkhead construction works which Tokyo Electric Power Co. has taken its share and executed. The structure of the bulkhead is a caisson type composite embankment. At the time of designing it, the east breakwater, the bulkhead and the public quay were already partially built, hence taking into consideration their shielding effects as well as relaxation of the construction conditions, its rational cross section has been determined and also ingenuity has been taxed on its actual construction work. 4 refs., 15 figs., 2 tabs.

  4. RESEARCH ON THE FLOATING OIL STORAGE SYSTEM FOR STRATEGIC PETROLEUM RESERVE

    Institute of Scientific and Technical Information of China (English)

    LI Wen-long

    2004-01-01

    The problem of petroleum safety is closely related to national politics and economics security and becomes one of key for discussion in China. The floating oil storage system has been proposed as a new facility for Strategic Petroleum Reserve (SPR) in our country. There are some differences in solving this problem. Although many of domestic research institutions are studying the project of SPR, the research is separate, and lack of comprehensive consideration, and fails to make a complete and scientific demonstration in many aspects, such as oil storage capacity, selection of storage sites, storage facilities, technologic and economic feasibility, risk assessment, etc. Therefore, no mature and systematic petroleum reserve theories have been formed up to now. Peoples argue the issue of objective of SPR, function, mode, cost, effect, etc. There are still many bifurcations, so, it is necessary to make more detailed demonstration, and provide some scientific decision-making strategy for the governments. In this paper, several significant problems are solved, for instance, the option of SPR facilities, the research on the principal characteristics of floating oil storage vessels, the analysis of mooring system for oil storage vessels, the design of breakwater and the calculation of failure probability, the risk assessment of floating oil storage system, etc.

  5. Hydraulic Modeling of A Curtain-Walled Dissipater by the Coupling of RANS and Boussinesq Equations

    Institute of Scientific and Technical Information of China (English)

    齐鹏; 王永学

    2002-01-01

    A hybrid numerical method for the hydraulic modeling of a curtain-walled dissipater of reflected waves from breakwa-ters is presented. In this method, a zonal approach that combines a nonlinear weakly dispersive wave (Boussinesq-typeequation) method and a Reynolds-Averaged Navier-Stokes (RANS) method is used. The Boussinesq-type equation issolved in the far field to describe wave transformation in shallow water. The RANS method is used in the near field to re-solve the turbulent boundary layer and vortex flows around the structure. Suitable matching conditions are enforced at theinterface between the viscous and the Boussinesq region. The Coupled RANS and Boussinesq method successfully resolvesthe vortex characteristics of flow in the vicinity of the structure, while unexpected phenomena like wave re-reflection areeffectively controlled by lengthening the Boussinesq region. Extensive results on hydraulic performance of a curtain-walleddissipater and the mechanism of dissipation of reflected waves are presented, providing a reference for minimization of thebreadth of the water chamber and for determination of the submerged depth of the curtain wall.

  6. Determining change of bathymetry with GPR method in Ordu-Giresun, a sea-filled airport in the Black Sea, Turkey

    Science.gov (United States)

    Kadioglu, Selma; Kagan Kadioglu, Yusuf

    2016-04-01

    Ordu-Giresun (OGU) is a newly-constructed airport, the first sea-filled airport in Turkey and in Europe, and the second airport in the world after Osaca-Japan. The airport is between Gulyalı district in Ordu city and Piraziz district in Giresun city in Black Sea -Turkey. A protection breakwater has been constructed by filling a rock approximately 7.435-m long and with an average height of 5.5 m. Then, the Black Sea has been filled until 1 m over the sea level, approximately the area is 1.770.000 m2 wide and includes a runway, aprons and taxiway covered by breakwater. The runway has a 1-m thickness, 3-km length and 45-m width, PCN84 strength, and stone mastic asphalt surface. The aprons has a 240 x 110 m length and PCN110 strength, the taxiway is 250 x 24 m wide. The airport was started to be constructed in July 2011 and it began to serve on 22th May 2015. The aim of this study was to determine the depth of the rock-filled layer and the amount of sinking of the bathymetry which has been determined before filling processing. In addition, before bathymetry determination, unconsolidated sediments had been removed from the bottom of the sea. There were four drilling points to control the sinking of the bathymetry. Therefore, six suitable Ground Penetrating Radar (GPR) profiles were measured, crossing these points with runway and aprons, using 250-MHz and 100-MHz shielded antennas. Starting points of the profiles were in the middle of the runway to merge between depth and thickness changing of the filled layer and bathymetry along the profiles. Surface topography changing was measured spaced 1 m apart with 1 cm sensitivity on each profile. At the same time, similarly the topography changing, bathymetry coordinates was re-arranged along the each profile. Topography corrections were applied to the processed radargrams and then the bottom boundary lines of the rock-filled layer were determined. The maximum height was 3.5 m according to the sea level, which was on the

  7. Anthropogenic disturbance can determine the magnitude of opportunistic species responses on marine urban infrastructures.

    Directory of Open Access Journals (Sweden)

    Laura Airoldi

    Full Text Available BACKGROUND: Coastal landscapes are being transformed as a consequence of the increasing demand for infrastructures to sustain residential, commercial and tourist activities. Thus, intertidal and shallow marine habitats are largely being replaced by a variety of artificial substrata (e.g. breakwaters, seawalls, jetties. Understanding the ecological functioning of these artificial habitats is key to planning their design and management, in order to minimise their impacts and to improve their potential to contribute to marine biodiversity and ecosystem functioning. Nonetheless, little effort has been made to assess the role of human disturbances in shaping the structure of assemblages on marine artificial infrastructures. We tested the hypothesis that some negative impacts associated with the expansion of opportunistic and invasive species on urban infrastructures can be related to the severe human disturbances that are typical of these environments, such as those from maintenance and renovation works. METHODOLOGY/PRINCIPAL FINDINGS: Maintenance caused a marked decrease in the cover of dominant space occupiers, such as mussels and oysters, and a significant enhancement of opportunistic and invasive forms, such as biofilm and macroalgae. These effects were particularly pronounced on sheltered substrata compared to exposed substrata. Experimental application of the disturbance in winter reduced the magnitude of the impacts compared to application in spring or summer. We use these results to identify possible management strategies to inform the improvement of the ecological value of artificial marine infrastructures. CONCLUSIONS/SIGNIFICANCE: We demonstrate that some of the impacts of globally expanding marine urban infrastructures, such as those related to the spread of opportunistic, and invasive species could be mitigated through ecologically-driven planning and management of long-term maintenance of these structures. Impact mitigation is a

  8. Sediment Transport Along the Coast of Israel: Examination of Fluorescent Sand Tracers [Case Study: Fluorescent Tracer Applications for Sediment Transport Investigations

    International Nuclear Information System (INIS)

    The method of labeled natural sand particles was used to study sediment transport along the central Mediterranean coast of Israel. Six portions of 300 kg each were tagged with various fluorescent colors, and distributed at six different locations in the vicinity of the Herzliya Marina. The tagged sand was scattered at the end of autumn, and sampled three times during the winter. Sampling was interrupted in mid-January because of unexpected dredging at the marina canal entrance. The samples were analyzed at the Yigal Allon Kinneret Limnological Laboratory. The wave climate during that time was analyzed using wave data from Ashdod (40 km south). Seven wave storms with significant wave heights of over 2.5 m were observed. Two of them clearly indicate a dominant direction from the southwest and two others from the northwest. However, the time durations and the relative angles between the wave directions and the orthogonal to the coast of the storms propagating from the southwest are essentially larger than those arriving from the northwest. The following results were noted: (i) The drift of tagged sand particles correlated to longshore sediment transport at all depths was in a northern direction throughout the field experiment. The longest distance of transport was 5 km over a period of 86 days. (ii) ''Onshore'' sediment transport was present; sand from 15 m depth was found at 8 m depth. (iii) The cross-shore sediment transport carried sand to a depth of 8 m, but no colored sand from shallow water (2-4 m) was found deeper than 8 m. (iv) Although sedimentation at the marina entrance during the experiment was high, only small amounts of tagged sand were found at the entrance. (v) Findings of tagged sand showed the main area of sedimentation to be along the marina's main breakwater. (author)

  9. The hydraulic performance and structural integrity of A-Jack armour layer

    Institute of Scientific and Technical Information of China (English)

    William G.McDougal

    2010-01-01

    A-Jacks are concrete armor units that are used in both open channel and coastal applications.In open channel applications,they are used for bank and toe protection,flow and grade control,bridge pier scour protection,energy dissipation,and habitat.These small units may be fabricated in standard block machines.In coastal applications,A-Jacks are used in breakwaters,jetties,revetments,and habitat development.Coastal units are generally much larger and more robust than the small open channel units.This paper focuses on coastal applications and in particular,combines results on three topics: (1) recent hydraulic model studies, (2) ahemative fabrication methods,and(3) bundle placement construction methods.Hydraulic models studies were conducted that examined the standard random and uniform placement methods, and also the bundle placement method.In bundle placement, 3~20 A-Jacks are banded together,lifted with a spreader bar, and placed as a single crone pick.This significantly decreases installation time during construction.It also provides a more hydraulically stable placement technique.The hydraulic model tests examined the bundle stability fn random waves for cases where the binding remains in tack and is removed.The geometry of A-Jacks enables a variety of fabrication techniques.One option is to fabricate the A-Jacks as two pieces using flat forms and then grout the two pieces together.Flat forms may be used in conventional block machines for A-Jacks sizes up to 1.3 re.Larger sizes may be wet cast in flat forms or gang forms.The A-Jacks geometry has been recently modified to increase grouting efficient and strength.Large A-Jacks may also be east in a single piece using "clam shell" type forms.

  10. Response to the 2011 Great East Japan Earthquake and Tsunami disaster.

    Science.gov (United States)

    Koshimura, Shunichi; Shuto, Nobuo

    2015-10-28

    We revisited the lessons of the 2011 Great East Japan Earthquake Tsunami disaster specifically on the response and impact, and discussed the paradigm shift of Japan's tsunami disaster management policies and the perspectives for reconstruction. Revisiting the modern histories of Tohoku tsunami disasters and pre-2011 tsunami countermeasures, we clarified how Japan's coastal communities have prepared for tsunamis. The discussion mainly focuses on structural measures such as seawalls and breakwaters and non-structural measures of hazard map and evacuation. The responses to the 2011 event are discussed specifically on the tsunami warning system and efforts to identify the tsunami impacts. The nation-wide post-tsunami survey results shed light on the mechanisms of structural destruction, tsunami loads and structural vulnerability to inform structural rehabilitation measures and land-use planning. Remarkable paradigm shifts in designing coastal protection and disaster mitigation measures were introduced, leading with a new concept of potential tsunami levels: Prevention (Level 1) and Mitigation (Level 2) levels according to the level of 'protection'. The seawall is designed with reference to Level 1 tsunami scenario, while comprehensive disaster management measures should refer to Level 2 tsunami for protection of human lives and reducing potential losses and damage. Throughout the case study in Sendai city, the proposed reconstruction plan was evaluated from the tsunami engineering point of view to discuss how the post 2011 paradigm was implemented in coastal communities for future disaster mitigation. The analysis revealed that Sendai city's multiple protection measures for Level 2 tsunami will contribute to a substantial reduction of the tsunami inundation zone and potential losses, combined with an effective tsunami evacuation plan. PMID:26392623

  11. Recent Extreme Marine Events at Southern Coast of Black Sea

    Science.gov (United States)

    Ozyurt Tarakcioglu, Gulizar; Cevdet Yalciner, Ahmet; Kirezci, Cagil; Baykal, Cuneyt; Gokhan Guler, Hasan; Erol, Onur; Zaytsev, Andrey; Kurkin, Andrey

    2015-04-01

    The utilization at the coastal areas of Black Sea basin has increased in the recent years with the projects such as large commercial ports, international transportation hubs, gas and petrol pipelines, touristic and recreational infrastructures both along surrounding shoreline. Although Black Sea is a closed basin, extreme storms and storm surges have also been observed with an increasing frequency in the recent years. Among those events, February 1999, March 2013 and September 2014 storms impacted Southern coast of Black sea have clearly shown that the increasing economic value at the coastal areas caused the increasing cost of damages and loss of property by natural hazards. The storm occurred on February 19-20, 1999 is one of the most destructive storm in the last decades. The 1999 event (1999 Southern Black sea storm) caused destruction at all harbors and coastal protection structures along the Black Sea coast of Turkey. The complete damage of the breakwater of Giresun Harbor and damage on the harbor structures and cargo handling equipment were the major impacts of the 1999 Southern Black sea storm. Similar coastal impact have also been observed during the September 24, 2014 storm at 500m East of Giresun harbor. Although there are considerable number of destructive storms observed at southern coast of Black sea recently, data on these events are limited and vastly scattered. In this study the list of recent extreme marine events at South coast of the Black sea compiled and related data such as wind speed, wave height, period, and type of damages are cataloged. Particular attention is focused on the 1999 and 2014 storm events. The meteorological and morphological characteristics which may be considered as the reasons of the generation and coastal amplification of these storms are discussed. ACKNOWLEDGEMENTS: This study is partly supported by Turkish Russian Joint Research Grant Program by TUBITAK (Turkey) and RFBR (Russia), and TUBITAK 213M534 Research Project.

  12. A geological perspective on the degradation and conservation of western Atlantic coral reefs.

    Science.gov (United States)

    Kuffner, Ilsa B; Toth, Lauren T

    2016-08-01

    Continuing coral-reef degradation in the western Atlantic is resulting in loss of ecological and geologic functions of reefs. With the goal of assisting resource managers and stewards of reefs in setting and measuring progress toward realistic goals for coral-reef conservation and restoration, we examined reef degradation in this region from a geological perspective. The importance of ecosystem services provided by coral reefs-as breakwaters that dissipate wave energy and protect shorelines and as providers of habitat for innumerable species-cannot be overstated. However, the few coral species responsible for reef building in the western Atlantic during the last approximately 1.5 million years are not thriving in the 21st century. These species are highly sensitive to abrupt temperature extremes, prone to disease infection, and have low sexual reproductive potential. Their vulnerability and the low functional redundancy of branching corals have led to the low resilience of western Atlantic reef ecosystems. The decrease in live coral cover over the last 50 years highlights the need for study of relict (senescent) reefs, which, from the perspective of coastline protection and habitat structure, may be just as important to conserve as the living coral veneer. Research is needed to characterize the geological processes of bioerosion, reef cementation, and sediment transport as they relate to modern-day changes in reef elevation. For example, although parrotfish remove nuisance macroalgae, possibly promoting coral recruitment, they will not save Atlantic reefs from geological degradation. In fact, these fish are quickly nibbling away significant quantities of Holocene reef framework. The question of how different biota covering dead reefs affect framework resistance to biological and physical erosion needs to be addressed. Monitoring and managing reefs with respect to physical resilience, in addition to ecological resilience, could optimize the expenditure of resources

  13. Alexandria (Al Iskandariya), Egypt

    Science.gov (United States)

    2002-01-01

    This image of Alexandria was taken by astronauts on board the International Space Station in December 2000 using an Electronic Still Camera. A wider-angle view (STS088-739-90) taken from the Space Shuttle in December 1998 is available for context. Alexandria (Al Iskandariya) occupies a T-shaped peninsula and strip of land separating the Mediterranean from Lake Mariout. Originally the town was built upon a mole (stone breakwater) called Heptastadium, which joined the island of Pharos (see referenced website, below) to the mainland. Since then sedimentary deposits have widened the mole. Since 1905, when the 370,000 Alexandrians lived in an area of about 4 sq km between the two harbors, the city (population 4 million; see referenced website, below) has grown beyond its medieval walls and now occupies an area of about 300 sq km. The Mahmudiya Canal, connecting Alexandria with the Nile, runs to the south of the city and, by a series of locks, enters the harbor of the principal port of Egypt (note ships). The reddish and ochre polygons west of Lake Mariout are salt-evaporation, chemical-storage, and water-treatment ponds within the coastal lagoon. Reference Youssef Halim and Fatma Abou Shouk, 2000, Human impacts on Alexandria's marine environment: UNESCO, Coastal Regions and Small Islands Unit (CSI), Coastal Management Sourcebooks 2 (accessed December 20, 2000) Additional photographs taken by astronauts can be viewed at NASA-JSC's Gateway to Astronaut Photography of Earth. Image ISS001-ESC-5025 provided by the Earth Sciences and Image Analysis Laboratory, Johnson Space Center.

  14. Growth Rate of Acropora formosa Fragments that Transplanted on Artificial Substrate Made from Coral Rubble

    Directory of Open Access Journals (Sweden)

    NUR FADLI

    2009-10-01

    Full Text Available Coral reefs play an important physiological and ecological role in coastal ecosystems such as providing natural breakwaters that protect shorelines and human settlements from waves and storm. Corals killed by tsunami, waves and storms are often degraded into rubble. This rubble is dynamic, easily shifted by currents and storms, which effectively forms ‘‘killing fields’’ for coral juveniles, hindering coral recovery. In order to rehabilitate coral reefs, artificial substrates are used both for coral transplantation and recruitment. Unfortunately, most artificial substrates are expensive and use land-based material such as concrete/cement-bases. In order to develop a new low-cost artificial substrate that can replace concrete/cement-base as a media for coral transplantation, modified coral rubble was tested in a pilot study in Seribu Island, Jakarta. Two different nets (nylon and polyethylene were used to form rubble into a compact shape, stable and strong substrate. The stability of the rubble and the complexity of the surface which is created by the net make this substrate suitable for coral transplantation. Additionally, from an economic perspective the nets are very cheap and locally available. In a number of experiments, modified coral rubble successfully replaced the concrete/cement-base as a media for coral transplantation. The coral transplants were growing over time. With this method, we can try to rehabilitate the degraded coral reef destroyed by tsunami or other factors with material that already is available at the site and with less money. However, this approach requires testing at additional sites and for longer periods, to determine the replicability of the results.

  15. A geological perspective on the degradation and conservation of western Atlantic coral reefs.

    Science.gov (United States)

    Kuffner, Ilsa B; Toth, Lauren T

    2016-08-01

    Continuing coral-reef degradation in the western Atlantic is resulting in loss of ecological and geologic functions of reefs. With the goal of assisting resource managers and stewards of reefs in setting and measuring progress toward realistic goals for coral-reef conservation and restoration, we examined reef degradation in this region from a geological perspective. The importance of ecosystem services provided by coral reefs-as breakwaters that dissipate wave energy and protect shorelines and as providers of habitat for innumerable species-cannot be overstated. However, the few coral species responsible for reef building in the western Atlantic during the last approximately 1.5 million years are not thriving in the 21st century. These species are highly sensitive to abrupt temperature extremes, prone to disease infection, and have low sexual reproductive potential. Their vulnerability and the low functional redundancy of branching corals have led to the low resilience of western Atlantic reef ecosystems. The decrease in live coral cover over the last 50 years highlights the need for study of relict (senescent) reefs, which, from the perspective of coastline protection and habitat structure, may be just as important to conserve as the living coral veneer. Research is needed to characterize the geological processes of bioerosion, reef cementation, and sediment transport as they relate to modern-day changes in reef elevation. For example, although parrotfish remove nuisance macroalgae, possibly promoting coral recruitment, they will not save Atlantic reefs from geological degradation. In fact, these fish are quickly nibbling away significant quantities of Holocene reef framework. The question of how different biota covering dead reefs affect framework resistance to biological and physical erosion needs to be addressed. Monitoring and managing reefs with respect to physical resilience, in addition to ecological resilience, could optimize the expenditure of resources

  16. A geological perspective on the degradation and conservation of western Atlantic coral reefs

    Science.gov (United States)

    Kuffner, Ilsa B.; Toth, Lauren

    2016-01-01

    Continuing coral-reef degradation in the western Atlantic is resulting in loss of ecological and geologic functions of reefs. With the goal of assisting resource managers and stewards of reefs in setting and measuring progress toward realistic goals for coral-reef conservation and restoration, we examined reef degradation in this region from a geological perspective. The importance of ecosystem services provided by coral reefs—as breakwaters that dissipate wave energy and protect shorelines and as providers of habitat for innumerable species—cannot be overstated. However, the few coral species responsible for reef building in the western Atlantic during the last approximately 1.5 million years are not thriving in the 21st century. These species are highly sensitive to abrupt temperature extremes, prone to disease infection, and have low sexual reproductive potential. Their vulnerability and the low functional redundancy of branching corals have led to the low resilience of western Atlantic reef ecosystems. The decrease in live coral cover over the last 50 years highlights the need for study of relict (senescent) reefs, which, from the perspective of coastline protection and habitat structure, may be just as important to conserve as the living coral veneer. Research is needed to characterize the geological processes of bioerosion, reef cementation, and sediment transport as they relate to modern-day changes in reef elevation. For example, although parrotfish remove nuisance macroalgae, possibly promoting coral recruitment, they will not save Atlantic reefs from geological degradation. In fact, these fish are quickly nibbling away significant quantities of Holocene reef framework. The question of how different biota covering dead reefs affect framework resistance to biological and physical erosion needs to be addressed. Monitoring and managing reefs with respect to physical resilience, in addition to ecological resilience, could optimize the expenditure of

  17. Sediment transport and decadal morphodynamic changes in the Tang Estuary with a Re-Migrating inlet, Iranian Coastline of the Oman Sea

    Science.gov (United States)

    Nosratpour, Behrouz; Amjadi, Soma; Haghshenas, S. Abbas

    2016-04-01

    The Tang Estuary located on the Iranian Coastline of the Oman Sea, The estuary's inlet is a rare re-migrating one which connects the Tang bay/estuary to the Oman Sea. The estuary experiences considerable floods and sediment load during occasional intense rainy periods. The upstream watershed supplies the narrow inlet channel with heavy sediment load twice a year on average. Moreover, a reef acts as a headland/natural offshore breakwater, which results in the formation of a tombolo in front of the estuary inlet. The most important feature of the system is the migration of the channel and the inlet which has occurred at least three times during the past 50 years. Considering the importance of this dynamic system and corresponding sediment discharge, physiography and watershed analysis of the Tang Estuary is investigated and sediment discharge from the channel and its sand content are estimated in the first step. A numerical model has been utilized to investigate cases of flow and sediment transport behaviour in the coastal Tang area and future migration patterns of the re-migrating inlet is estimated. The morphodynamic changes are investigated by analysing two sets of aerial photos taken in 1967 and 1993, a series of high resolution satellite images from 2008 and 33 series of lower resolution data in the period of 1966 to 2015 in a GIS framework to investigate decadal evolution of the Tang Estuary the past five decades. Eventually, numerical results are compared with field observations and comprehensive GIS based analysis of historic shoreline changes from aerial photos and satellite imagery. Management guidelines and suggestions are deducted and drawn from the calibration and verification of the results with field observations and satellite image analysis.

  18. An Investigation on the Formation of Submerged Bar Under Surges in Sandy Coastal Region

    Institute of Scientific and Technical Information of China (English)

    Mustafa DEM(I)RC(I); M.Sami AK(O)Z

    2012-01-01

    Cross-shore sediment transport rate exposed to waves is very important for coastal morphology,the design of marine structures such as seawalls,jetties,breakwaters etc,and the prevention of coastal erosion and accretion due to onoff shore sediment transportation.In the present study,the experiments on cross-shore sediment transport are carried out in a laboratory wave channel with initial beach slopes of 1/8,1/10 and 1/15.By using the regular waves with different deep-water wave steepnesses generated by a pedal-type wave generator,the geometrical characteristics of beach profiles under storm conditions and the parameters affecting on-off shore sediment transport are investigated for the beach materials with medium diameters of d50=0.25,0.32,0.45,0.62 and 0.80 mm.The offshore bar geometric characteristics are the horizontal distances from the shoreline to the bar beginning (Xb),crest (Xt),and ending (Xs) points,the depth from the bar crest to the still water level (ht),and the bar volume (Vbar).The experimental results have indicated that when the deep-water steepness (H0/L0) increased,the net movement to seaside increased.With the increasing wave steepness,the bars moved to widen herewith the vertical distances from still water level to the bar beginning (Xb),crest (Xt) and ending (Xs) points and the horizontal distances from the coast line to the bar beginning,crest and ending points increased.It was also shown from experimental results that the horizontal distances from the bar beginning and ending points to the coast line increased with the decrease of the beach slope.The experimental results obtained from this study are compared with previous experimental work and found to be of the same magnitude as the experimental measurements and followed the expected basic trend.

  19. Three-dimensional numerical modeling of nearshore circulation

    Institute of Scientific and Technical Information of China (English)

    SUN Detong

    2008-01-01

    A three-dimensional nearshore circulation model was developed by coupling CH3D, a three-dimensional hydrodynamic model and REF/DIF, a nearsbore wave transformation model. The model solves the three-dimensional wave-averaged equations of motion. Wave-induced effects on circulation were introduced in the form of radiation stresses, wave-induced mass transport, wave-induced enhancement of bottom friction and wave-induced turbulent mixing. Effects of breaking waves were considered following Svendsen (1984a and 1984b) and Stive and Wind (1986). The model was successfully tested against the analytical solution of longshore currents by Longuet and Higgins (1970). The model successfully simulated the undertow as observed in a laboratory experiment by Stive and Wind (1982). In addition, the model was applied to a physical model by Mory and Hamm (1997) and successfully reproduced the eddy behind a detached breakwater as well as the longshore current on the open beach and the contiguous eddy in the open area of the wave tank. While the qualitative agreement between model results and experimental observations was very good, the quantitative agreement needs to be further improved. Albeit difficult to explain every discrepancy between the model re- suits and observations, in general, sources of errors are attributed to the lack of understanding and comprehensive description of following processes: (1) the horizontal and vertical distribution of radiation stress, especially for breaking waves; (2) the detailed structure of turbulence;(3)Wave-current interaction (not included at this moment) ; and (4)the wave- current boundary layer and the resulting bottom shear stress.

  20. Balancing Power Absorption and Structural Loading for an Assymmetric Heave Wave-Energy Converter in Regular Waves: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Tom, Nathan M.; Madhi, Farshad; Yeung, Ronald W.

    2016-07-01

    The aim of this paper is to maximize the power-to-load ratio of the Berkeley Wedge: a one-degree-of-freedom, asymmetrical, energy-capturing, floating breakwater of high performance that is relatively free of viscosity effects. Linear hydrodynamic theory was used to calculate bounds on the expected time-averaged power (TAP) and corresponding surge restraining force, pitch restraining torque, and power take-off (PTO) control force when assuming that the heave motion of the wave energy converter remains sinusoidal. This particular device was documented to be an almost-perfect absorber if one-degree-of-freedom motion is maintained. The success of such or similar future wave energy converter technologies would require the development of control strategies that can adapt device performance to maximize energy generation in operational conditions while mitigating hydrodynamic loads in extreme waves to reduce the structural mass and overall cost. This paper formulates the optimal control problem to incorporate metrics that provide a measure of the surge restraining force, pitch restraining torque, and PTO control force. The optimizer must now handle an objective function with competing terms in an attempt to maximize power capture while minimizing structural and actuator loads. A penalty weight is placed on the surge restraining force, pitch restraining torque, and PTO actuation force, thereby allowing the control focus to be placed either on power absorption or load mitigation. Thus, in achieving these goals, a per-unit gain in TAP would not lead to a greater per-unit demand in structural strength, hence yielding a favorable benefit-to-cost ratio. Demonstrative results in the form of TAP, reactive TAP, and the amplitudes of the surge restraining force, pitch restraining torque, and PTO control force are shown for the Berkeley Wedge example.

  1. Transect based analysis versus area based analysis to quantify shoreline displacement: spatial resolution issues.

    Science.gov (United States)

    Anfuso, Giorgio; Bowman, Dan; Danese, Chiara; Pranzini, Enzo

    2016-10-01

    Field surveys, aerial photographs, and satellite images are the most commonly employed sources of data to analyze shoreline position, which are further compared by area based analysis (ABA) or transect based analysis (TBA) methods. The former is performed by computing the mean shoreline displacement for the identified coastal segments, i.e., dividing the beach area variation by the segment length; the latter is based on the measurement of the distance between each shoreline at set points along transects. The present study compares, by means of GIS tools, the ABA and TBA methods by computing shoreline displacements recorded on two stretches of the Tuscany coast (Italy): the beaches of Punta Ala, a linear coast without shore protection structures, and the one at Follonica, which is irregular due to the presence of groins and detached breakwaters. Surveys were carried out using a differential global positioning system (DGPS) in RTK mode. For each site, a 4800-m-long coastal segment was analyzed and divided into ninety-six 50-m-long sectors for which changes were computed using both the ABA and TBA methods. Sectors were progressively joined to have a length of 100, 200, 400, and 800 m to examine how this influenced results. ABA and TBA results are highly correlated for transect distance and sector length up to 100 m at both investigated locations. If longer transects are considered, the two methods still produce good correlated data on the smooth shoreline (i.e. at Punta Ala), but correlation became significantly lower on the irregular shoreline (i.e., at Follonica). PMID:27640163

  2. Geomorphic factors related to the persistence of subsurface oil from the Exxon Valdez oil spill

    Science.gov (United States)

    Nixon, Zachary; Michel, Jacqueline; Hayes, Miles O.; Irvine, Gail V.; Short, Jeffrey

    2013-01-01

    Oil from the 1989 Exxon Valdez oil spill has persisted along shorelines of Prince William Sound, Alaska, for more than two decades as both surface and subsurface oil residues. To better understand the distribution of persistent subsurface oil and assess the potential need for further restoration, a thorough and quantitative understanding of the geomorphic factors controlling the presence or absence of subsurface oil is required. Data on oiling and geomorphic features were collected at 198 sites in Prince William Sound to identify and quantify the relationships among these geomorphic factors and the presence and absence of persistent subsurface oil. Geomorphic factors associated with the presence of subsurface oil were initial oil exposure, substrate permeability, topographic slope, low exposure to waves, armoring on gravel beaches, tombolos, natural breakwaters, and rubble accumulations. Geomorphic factors associated with the absence of subsurface oil were impermeable bedrock; platforms with thin sediment veneer; fine-grained, well-sorted gravel beaches with no armor; and low-permeability, raised bay-bottom beaches. Relationships were found between the geomorphic and physical site characteristics and the likelihood of encountering persistent subsurface oiling at those sites. There is quantitative evidence of more complex interactions between the overall wave energy incident at a site and the presence of fine-scale geomorphic features that may have provided smaller, local wave energy sheltering of oil. Similarly, these data provide evidence for interactions between the shoreline slope and the presence of angular rubble, with decreased likelihood for encountering subsurface oil at steeply sloped sites except at high-angle sheltered rubble shoreline locations. These results reinforce the idea that the interactions of beach permeability, stability, and site-specific wave exposure are key drivers for subsurface oil persistence in exposed and intermittently exposed mixed

  3. Radio Frequency Identification (RFID) technology applied to the definition of underwater and subaerial coarse sediment movement

    Science.gov (United States)

    Bertoni, Duccio; Sarti, Giovanni; Benelli, Giuliano; Pozzebon, Alessandro; Raguseo, Gianluca

    2010-07-01

    In this paper, Radio Frequency Identification technology has been applied to track both underwater and subaerial displacement of pebbles along an artificial coarse beach at Marina di Pisa, Italy. Several preliminary laboratory tests have been performed to adapt the RFID technique for underwater use, which has been the primary impediment to this promising approach to the study of coarse sediment transport and movement. Tests showed the reliability of low frequencies for this kind of work, since they enable good signal transmission and reception through water. Passive ABS plastic transponders were inserted into about 100 pebbles and released onto the beach in March, 2009. A CORE-125 reader was chosen as the operating antenna to continuously transmit low frequency (125 kHz) signals. An acoustic signal toned whenever a pebble was detected while the unambiguous identification code of the pebble is shown immediately on the screen of a laptop connected to the reader. The positions of the pebbles were recorded with a total station. After two months (May, 2009), 74 marked pebbles were retrieved, 77% of the total. The positions of the retrieved pebbles were also recorded with the total station, thus allowing calculation of the coarse sediment transport tendency. About 60% of the recovered pebbles (44 out of 74) were found on the upper shoreface. The analysis of the marked pebble trajectories revealed a divergent transport movement in the northernmost sector of the beach. This movement was probably triggered by an irregularity of the submerged breakwater fronting the shoreline. The southern sector is characterised by chaotic pathways related to the formation and evolution of beach cusps. This outcome highlights and confirms the importance of a complete definition of the beach system, with no separation between the underwater and the subaerial portion of the shore when it comes to sediment transport and movement. This successful application of RFID technology to the underwater

  4. Digital Elevation Model from Non-Metric Camera in Uas Compared with LIDAR Technology

    Science.gov (United States)

    Dayamit, O. M.; Pedro, M. F.; Ernesto, R. R.; Fernando, B. L.

    2015-08-01

    Digital Elevation Model (DEM) data as a representation of surface topography is highly demanded for use in spatial analysis and modelling. Aimed to that issue many methods of acquisition data and process it are developed, from traditional surveying until modern technology like LIDAR. On the other hands, in a past four year the development of Unamend Aerial System (UAS) aimed to Geomatic bring us the possibility to acquire data about surface by non-metric digital camera on board in a short time with good quality for some analysis. Data collectors have attracted tremendous attention on UAS due to possibility of the determination of volume changes over time, monitoring of the breakwaters, hydrological modelling including flood simulation, drainage networks, among others whose support in DEM for proper analysis. The DEM quality is considered as a combination of DEM accuracy and DEM suitability so; this paper is aimed to analyse the quality of the DEM from non-metric digital camera on UAS compared with a DEM from LIDAR corresponding to same geographic space covering 4 km2 in Artemisa province, Cuba. This area is in a frame of urban planning whose need to know the topographic characteristics in order to analyse hydrology behaviour and decide the best place for make roads, building and so on. Base on LIDAR technology is still more accurate method, it offer us a pattern for test DEM from non-metric digital camera on UAS, whose are much more flexible and bring a solution for many applications whose needs DEM of detail.

  5. Comparison of Laboratory Experimental Data to XBeach Numerical Model Output

    Science.gov (United States)

    Demirci, Ebru; Baykal, Cuneyt; Guler, Isikhan; Sogut, Erdinc

    2016-04-01

    generating data sets for testing and validation of sediment transport relationships for sand transport in the presence of waves and currents. In these series, there is no structure in the basin. The second and third series of experiments were designed to generate data sets for development of tombolos in the lee of detached 4m-long rubble mound breakwater that is 4 m from the initial shoreline. The fourth series of experiments are conducted to investigate tombolo development in the lee of a 4m-long T-head groin with the head section in the same location of the second and the third tests. The fifth series of experiments are used to investigate tombolo development in the lee of a 3-m-long rubble-mound breakwater positioned 1.5 m offshore of the initial shoreline. In this study, the data collected from the above mentioned five experiments are used to compare the results of the experimental data with XBeach numerical model results, both for the "no-structure" and "with-structure" cases regarding to sediment transport relationships in the presence of only waves and currents as well as the shoreline changes together with the detached breakwater and the T-groin. The main purpose is to investigate the similarities and differences between the laboratory experimental data behavior with XBeach numerical model outputs for these five cases. References: Baykal, C., Sogut, E., Ergin, A., Guler, I., Ozyurt, G.T., Guler, G., and Dogan, G.G. (2015). Modelling Long Term Morphological Changes with XBeach: Case Study of Kızılırmak River Mouth, Turkey, European Geosciences Union, General Assembly 2015, Vienna, Austria, 12-17 April 2015. Gravens, M.B. and Wang, P. (2007). "Data report: Laboratory testing of longshore sand transport by waves and currents; morphology change behind headland structures." Technical Report, ERDC/CHL TR-07-8, Coastal and Hydraulics Laboratory, US Army Engineer Research and Development Center, Vicksburg, MS. Roelvink, D., Reniers, A., van Dongeren, A., van Thiel de

  6. Comparison of Laboratory Experimental Data to XBeach Numerical Model Output

    Science.gov (United States)

    Demirci, Ebru; Baykal, Cuneyt; Guler, Isikhan; Sogut, Erdinc

    2016-04-01

    generating data sets for testing and validation of sediment transport relationships for sand transport in the presence of waves and currents. In these series, there is no structure in the basin. The second and third series of experiments were designed to generate data sets for development of tombolos in the lee of detached 4m-long rubble mound breakwater that is 4 m from the initial shoreline. The fourth series of experiments are conducted to investigate tombolo development in the lee of a 4m-long T-head groin with the head section in the same location of the second and the third tests. The fifth series of experiments are used to investigate tombolo development in the lee of a 3-m-long rubble-mound breakwater positioned 1.5 m offshore of the initial shoreline. In this study, the data collected from the above mentioned five experiments are used to compare the results of the experimental data with XBeach numerical model results, both for the "no-structure" and "with-structure" cases regarding to sediment transport relationships in the presence of only waves and currents as well as the shoreline changes together with the detached breakwater and the T-groin. The main purpose is to investigate the similarities and differences between the laboratory experimental data behavior with XBeach numerical model outputs for these five cases. References: Baykal, C., Sogut, E., Ergin, A., Guler, I., Ozyurt, G.T., Guler, G., and Dogan, G.G. (2015). Modelling Long Term Morphological Changes with XBeach: Case Study of Kızılırmak River Mouth, Turkey, European Geosciences Union, General Assembly 2015, Vienna, Austria, 12-17 April 2015. Gravens, M.B. and Wang, P. (2007). "Data report: Laboratory testing of longshore sand transport by waves and currents; morphology change behind headland structures." Technical Report, ERDC/CHL TR-07-8, Coastal and Hydraulics Laboratory, US Army Engineer Research and Development Center, Vicksburg, MS. Roelvink, D., Reniers, A., van Dongeren, A., van Thiel de

  7. Sedimentary facies and sedimentary processes of the 2011 Tohoku-oki tsunami deposit with diversified grain size distribution

    Science.gov (United States)

    Yamada, M.; Fujino, S.; Goto, K.

    2012-12-01

    Most of the reported modern tsunami deposits are composed of sand, but gravelly tsunami deposits are rarely reported so far. While, gravely deposits that are considered as the possible paleotsunami deposits have often been identified in the geologic stratum. To expand our knowledge about diversity of tsunami deposits and provide criteria to identify tsunami deposits in the strata, we described a deposit with diversified grain size distribution of the 2011 Tohoku-oki tsunami. As well as describing the deposit, we also reconstructed its sedimentary processes. The height of the 2011 Tohoku-oki tsunami reached up to 28.1 m above sea level and inundated up to 1.8 km inland at the study site in Miyako city, Iwate prefecture, Japan. Tsunami deposit with diversified grain size distribution (silt-cobble) covered the lowland that had been used to paddy fields. The layered tsunami deposit is composed of pebble and cobble near the shore, whereas it is composed of sand and silt near the inundation limit, showing general fining landward trend. The thickness of the deposit is 1 m or more near the shore and generally thins inland to be a few centimeters. Separate from the layered deposits, many boulders that are composed of broken pieces of breakwaters, wave-dissipating blocks and volcanic rocks were scattered on the lowland. The transportation and deposition of the boulders and layered deposits at the study site is one of the rare cases in the sense that the wide range of sedimentary grains was deposited concurrently by a tsunami. Most boulders were deposited until 750 m from the shoreline, and the current velocities estimated from the boulder sizes show rapid declination at the point. The seaward stretched local scours around the larger boulders represent that they were not moved by the return flow. The gravelly tsunami deposit shows a sharp decline in thickness and grain size where many of the boulders were stopped. These indicate that deceleration in run-up flow caused rapid

  8. The Effectiveness, Costs and Coastal Protection Benefits of Natural and Nature-Based Defences.

    Science.gov (United States)

    Narayan, Siddharth; Beck, Michael W; Reguero, Borja G; Losada, Iñigo J; van Wesenbeeck, Bregje; Pontee, Nigel; Sanchirico, James N; Ingram, Jane Carter; Lange, Glenn-Marie; Burks-Copes, Kelly A

    2016-01-01

    There is great interest in the restoration and conservation of coastal habitats for protection from flooding and erosion. This is evidenced by the growing number of analyses and reviews of the effectiveness of habitats as natural defences and increasing funding world-wide for nature-based defences-i.e. restoration projects aimed at coastal protection; yet, there is no synthetic information on what kinds of projects are effective and cost effective for this purpose. This paper addresses two issues critical for designing restoration projects for coastal protection: (i) a synthesis of the costs and benefits of projects designed for coastal protection (nature-based defences) and (ii) analyses of the effectiveness of coastal habitats (natural defences) in reducing wave heights and the biophysical parameters that influence this effectiveness. We (i) analyse data from sixty-nine field measurements in coastal habitats globally and examine measures of effectiveness of mangroves, salt-marshes, coral reefs and seagrass/kelp beds for wave height reduction; (ii) synthesise the costs and coastal protection benefits of fifty-two nature-based defence projects and; (iii) estimate the benefits of each restoration project by combining information on restoration costs with data from nearby field measurements. The analyses of field measurements show that coastal habitats have significant potential for reducing wave heights that varies by habitat and site. In general, coral reefs and salt-marshes have the highest overall potential. Habitat effectiveness is influenced by: a) the ratios of wave height-to-water depth and habitat width-to-wavelength in coral reefs; and b) the ratio of vegetation height-to-water depth in salt-marshes. The comparison of costs of nature-based defence projects and engineering structures show that salt-marshes and mangroves can be two to five times cheaper than a submerged breakwater for wave heights up to half a metre and, within their limits, become more cost

  9. The Effectiveness, Costs and Coastal Protection Benefits of Natural and Nature-Based Defences.

    Directory of Open Access Journals (Sweden)

    Siddharth Narayan

    Full Text Available There is great interest in the restoration and conservation of coastal habitats for protection from flooding and erosion. This is evidenced by the growing number of analyses and reviews of the effectiveness of habitats as natural defences and increasing funding world-wide for nature-based defences-i.e. restoration projects aimed at coastal protection; yet, there is no synthetic information on what kinds of projects are effective and cost effective for this purpose. This paper addresses two issues critical for designing restoration projects for coastal protection: (i a synthesis of the costs and benefits of projects designed for coastal protection (nature-based defences and (ii analyses of the effectiveness of coastal habitats (natural defences in reducing wave heights and the biophysical parameters that influence this effectiveness. We (i analyse data from sixty-nine field measurements in coastal habitats globally and examine measures of effectiveness of mangroves, salt-marshes, coral reefs and seagrass/kelp beds for wave height reduction; (ii synthesise the costs and coastal protection benefits of fifty-two nature-based defence projects and; (iii estimate the benefits of each restoration project by combining information on restoration costs with data from nearby field measurements. The analyses of field measurements show that coastal habitats have significant potential for reducing wave heights that varies by habitat and site. In general, coral reefs and salt-marshes have the highest overall potential. Habitat effectiveness is influenced by: a the ratios of wave height-to-water depth and habitat width-to-wavelength in coral reefs; and b the ratio of vegetation height-to-water depth in salt-marshes. The comparison of costs of nature-based defence projects and engineering structures show that salt-marshes and mangroves can be two to five times cheaper than a submerged breakwater for wave heights up to half a metre and, within their limits, become

  10. Integrated Modeling for the Assessment of Ecological Impacts of Sea Level Rise

    Science.gov (United States)

    Hagen, S. C.; Lewis, G.; Bartel, R.; Batten, B.; Huang, W.; Morris, J.; Slinn, D. N.; Sparks, J.; Walters, L.; Wang, D.; Weishampel, J.; Yeh, G.

    2010-12-01

    community to prioritize risk management strategies, reformulate set back requirements, improve guidelines for construction of breakwaters and other coastal infrastructure, and assess water resources impacts and protection needs.

  11. La inconformidad subversiva: entre el pronunciamiento y el bandidaje: Un acercamiento a los movimientos rebeldes durante el tuxtepecanismo, 1876-1888

    Directory of Open Access Journals (Sweden)

    Fausta Gantús

    2008-06-01

    Full Text Available En este artículo se analiza el universo porfiriano signado por el descontento, la inconformidad, la crítica y la protesta, es decir, esa otra cara de la realidad contra la cual el régimen sostuvo una lucha permanente porque su presencia contradecía sus pretensiones modernizadoras basadas en el orden y el progreso. El estudio se centra en 1888 por considerarlo un parteaguas en el Porfiriato, teniendo en cuenta que Díaz transitó de la defensa del precepto de la no-reelección a la acuñación de la idea del "hombre necesario" y la consecución de la reelección indefinida. Esgrimidas desde diversos sectores de la sociedad, en relación con las distintas instancias del poder nos interesa destacar aquellos recursos por medio de los cuales los actores exteriorizaron sus posiciones y reclamos. A partir de la información recabada en hemerografía de la época y en la consulta de algunos fondos documentales, se establece una clasificación inicial en la que es posible distinguir al menos dos vías de manifestación; primero, la que se inscribe dentro del marco de la legalidad y el respeto a las instituciones, y segundo, la que traspasa esa frontera convirtiéndose en subversiva. De esta última se ocupará este trabajo.This article analyzes the Porfirian universe, characterized by discontent, disagreement, criticism and protest, in other words, the other side of reality against which the regime engaged in a permanent struggle since its presence belied its attempts at modernization based on order and progress. The study focuses on 1888, regarded as a breakwater in the Porfiriato, bearing in mind the fact that Díaz shifted from the defense of the precept of non-reelection to the idea of the "necessary man" and the achievement of indefinite re-election. The author focuses on the ideas wielded by various sectors of society, in relation to the various corridors of power and the means used by actors to express their positions and claims. On the basis

  12. The Effectiveness, Costs and Coastal Protection Benefits of Natural and Nature-Based Defences.

    Science.gov (United States)

    Narayan, Siddharth; Beck, Michael W; Reguero, Borja G; Losada, Iñigo J; van Wesenbeeck, Bregje; Pontee, Nigel; Sanchirico, James N; Ingram, Jane Carter; Lange, Glenn-Marie; Burks-Copes, Kelly A

    2016-01-01

    There is great interest in the restoration and conservation of coastal habitats for protection from flooding and erosion. This is evidenced by the growing number of analyses and reviews of the effectiveness of habitats as natural defences and increasing funding world-wide for nature-based defences-i.e. restoration projects aimed at coastal protection; yet, there is no synthetic information on what kinds of projects are effective and cost effective for this purpose. This paper addresses two issues critical for designing restoration projects for coastal protection: (i) a synthesis of the costs and benefits of projects designed for coastal protection (nature-based defences) and (ii) analyses of the effectiveness of coastal habitats (natural defences) in reducing wave heights and the biophysical parameters that influence this effectiveness. We (i) analyse data from sixty-nine field measurements in coastal habitats globally and examine measures of effectiveness of mangroves, salt-marshes, coral reefs and seagrass/kelp beds for wave height reduction; (ii) synthesise the costs and coastal protection benefits of fifty-two nature-based defence projects and; (iii) estimate the benefits of each restoration project by combining information on restoration costs with data from nearby field measurements. The analyses of field measurements show that coastal habitats have significant potential for reducing wave heights that varies by habitat and site. In general, coral reefs and salt-marshes have the highest overall potential. Habitat effectiveness is influenced by: a) the ratios of wave height-to-water depth and habitat width-to-wavelength in coral reefs; and b) the ratio of vegetation height-to-water depth in salt-marshes. The comparison of costs of nature-based defence projects and engineering structures show that salt-marshes and mangroves can be two to five times cheaper than a submerged breakwater for wave heights up to half a metre and, within their limits, become more cost

  13. Tsunami Run-up Heights at Imwon Port, Korea

    Science.gov (United States)

    Cho, Yong-Sik; Cho, Jeong-Seon

    2015-04-01

    Tsunami Run-up Heights at Imwon Port, Korea Yong-Sik Cho and Jeong-Seon Cho Department of Civil and Environmental Engineering, Hanyang University 222 Wangsimni-ro, Seongdong-gu, Seoul 133-791, Korea. The Eastern Coast of the Korean Peninsula has been attacked frequently by a number of tsunamis causing severe damages during this century. Among them, 1983 Central East Sea and 1993 Hokkaido Tsunami events were recorded as the most devastating events in Korea. More recently, the Great East Japan Tsunami had also attacked the Korean Peninsula. The Eastern Coast of the Korean Peninsula is the terminal place where tsunamis climb up inland after it generated along the western coast of Japan. The central part of the coast, in special, is worried as a tsunami danger zone because much tsunami energy is concentrated on by a topographic condition of this region. Recently, several coastal facilities including harbors and breakwaters are built and operated along the Eastern Coast of the Korean Peninsula. Furthermore, several nuclear power plants are already operating and several more units are now under construction. Residents who lived alongside the coast want free from unexpected danger, so the tsunami hazard mitigation becomes an important issue of coastal problems in Korea. Through the historical tsunami events, the Imwon Port is known as the place where most severe damage occurred, especially in 1983. An effective and economic way for the tsunami hazard mitigation planning is to construct inundation maps along the coast vulnerable to tsunami flooding. These maps should be built based on the historical tsunami events and the projected scenarios. For this purpose, an accurate estimation of tsunami run-up height and inundation process through the numerical model is needed. As a first step to tsunami mitigation program, the maximum run-up heights at the Imwon Port are computed and compared with field observed data. For this, tsunami run-up heights in this region were filed

  14. The policies on the South China Sea and Strategic Orientation for Southeast Asia in Japan during early Cold War%冷战初期日本南海政策及东南亚战略取向

    Institute of Scientific and Technical Information of China (English)

    郭渊

    2014-01-01

    冷战使日本在美国的全球战略中作用提升,成为反共“防波堤”,其具有政治目的性的东南亚“经济外交”呈现出明显的海洋战略取向,且影响至今。因地缘利益、东南亚战略,日本南海政策的基本出发点自冷战开始后始终没变,即追随美国遏制中国政策,对南海诸岛归属问题上采取模糊态度和立场,这为后来南海周边某些国家侵占南海岛礁留下所谓借口。此时日本还曾插足于南海诸岛,由于海峡两岸对南海权益的维护使其非法行为无法为继,但随着经济的发展,日本越来越依赖南海航道和加大南海石油资源的开发,这决定其“关心”南海问题就是势所必然了。%The role of Japan is increased in the United States’ global strategy because of Cold War, and Japan become an anti-Communist"breakwater". Japan’s“economic diplomacy”of Southeast Asian which has a political purpose expresses a clear strategic orientation of the ocean. Due to geopolitical interests, Southeast Asia strategy, the basic starting point of Japan’s policy for South China Sea has not changed since the Cold War. That is to say, following the United States, Japan attempts to contain China’s development and adopts vague attitude and stance on the ownership of the South China Sea, which gives so-called excuses for some countries’ occuping the South China Sea reefs. At the same time, Japan participates in the South China Sea. As China maintains the ownership and interests of the South China Sea, Japan’s illegal behavior cannot continue. But with the development of the economy, Japan increasingly depends waterways and develops oil resources in the South China Sea, and this determines Japan to“concern”the issues of South China Sea.

  15. Medium-term shoreline evolution of the mediterranean coast of Andalusia (SW Spain)

    Science.gov (United States)

    Liguori, Vincenzo; Manno, Giorgio; Messina, Enrica; Anfuso, Giorgio; Suffo, Miguel

    2015-04-01

    Coastal environment is a dynamic system in which numerous natural processes are continuously actuating and interacting among them. As a result, geomorphologic, physical and biological characteristics of coastal environments are constantly changing. Such dynamic balance is nowadays seriously threatened by the strong and increasing anthropic pressure that favors erosion processes, and the associated loss of environmental, ecologic and economic aspects. Sandy beaches are the most vulnerable environments in coastal areas. The aim of this work was to reconstruct the historical evolution of the Mediterranean coastline of Andalusia, Spain. The investigated area is about 500 km in length and includes the provinces of Cadiz, Malaga, Granada and Almeria. It is essentially composed by cliffed sectors with sand and gravel pocket beaches constituting independent morphological cells of different dimensions. This study was based on the analysis of aerial photos and satellite images covering a period of 55 years, between 1956 and 2011. Aerial photos were scanned and geo-referenced in order to solve scale and distortion problems. The shoreline was considered and mapped through the identification of the wet / dry sand limit which coincides with the line of maximum run-up; this indicator - representing the shoreline at the moment of the photo - is the most easily identifiable and representative one in microtidal coastal environments. Since shoreline position is linked to beach profile characteristics and to waves, tide and wind conditions at the moment of the photo, such parameters were taken into account in the calculation of shoreline position and changes. Specifically, retreat/accretion changes were reconstructed applying the DSAS method (Digital Shoreline Analysis System) proposed by the US Geological Survey. Significant beach accretion was observed at Playa La Mamola (Granada), with +1 m/y, because the construction of five breakwaters, and at Playa El Cantal (Almeria) and close

  16. Numerical simulation of flow field using VOF method based on body-fitted grid%基于贴体网格的VOF方法数模流场研究

    Institute of Scientific and Technical Information of China (English)

    任冰; 李雪艳; 王国玉; 王永学

    2011-01-01

    提出了一种基于VOF方法的模拟具有复杂边界形状结构物附近流场的新算法,BFC—SIMPLE—VOF算法。采用坐标变换方法实现了任意复杂区域的结构化网格划分,在贴体网格下对二维不可压缩粘性流体的控制方程进行了离散。提出了基于交错网格的修正SIMPLE算法来迭代求解压力一速度场,修正了贴体坐标下的界面跟踪方法(VOF方法)。对带有弧形防浪墙的防波堤结构附近的流场和压力场进行了数值计算,并与在笛卡尔坐标网格下采用部分单元体近似描述结构物边界的原算法的计算结果进行了比较分析。%In the present study, a new algorithm-BFC-SIMPLE-VOF method based on VOF method was developed to model the flow field around the complex structures. Structured grids are achieved by the orthogonal coordinate transform method in the arbitrary complex region. The two-dimensional incompressible viscous flow was analyzed by solving Navier-Stokes equations on body-fitted curvilinear grids. The transformed SIMPLE scheme was adopted to modified the pressure-velocity field and the transformed VOF method was used to trace the free surface. The flow field and pressure field around the breakwater with curving wave wall were simulated using the new algorithm that was advanced in the paper, and was compared with the value that was achieved by the traditional rectangular grid which are approximated by steps.

  17. Currents, Water Budget and Turn-Over Time Within A Man-Made Coastal Mega-Structure: Palm Jumeirah, Southern Arabian Gulf, United Arab Emirates

    Science.gov (United States)

    Cavalcante, G.; Kjerfve, B.

    2009-05-01

    Large-scale land reclamation projects along the coastline of Dubai, United Arab Emirates (UAE), are set to expand from 45 km of natural shoreline to more than 1,500 km by 2010. The increasing scale of coastal development in Dubai has large-scale effects on water movement throughout the project area. Palm Jumeirah is the oldest, most well-developed of several man-made coastal mega-constructions in Dubai. This construction project started 6 years ago, has an overall surface area of 7.9 km2 and a footprint of 23 km2, and is connected to the coast via a 5-km long spine from the mainland to the crescent tip. We made time series observations of hydrographic properties and currents within the Palm Jumeirah Lagoon (PJL) during 29 days in April/May 2008 to examine the current flows, water budget, salt transport, and turn-over time. The currents and water flow within the PJL were quite variable, with stronger currents, greater material transports, lower water temperatures, and slightly lower salinities in areas close to the entrances where flushing is ample. Due to the shallow water depths, we found only weak vertical stratification during a tidal cycle. The lagoon system is comprised of 18 blind channels surrounded by a semi-circular open channel, which in turn is linked to the coastal waters by 4 gaps (one each on the East and West sides and two at the base of the development) in the rocky breakwater that surrounds the development. We found substantial differences in water discharge between the east and west gaps, with high discharge on average exiting the east gap and extremely low water discharge exiting the west gap. Our results indicate that the PJL is flushed unequally between the east and west sides with residence times of 1.2 and 42 days for the east and west sides of the development, respectively. Previous studies of water residence time using the DELFT3D hydrodynamics simulation modeling software did not capture this difference accurately, estimating residence

  18. Hurricane Sandy: Caught in the eye of the storm and a city's adaptation response

    Science.gov (United States)

    Orton, P. M.; Horton, R. M.; Blumberg, A. F.; Rosenzweig, C.; Solecki, W.; Bader, D.

    2015-12-01

    The NOAA RISA program has funded the seven-institution Consortium for Climate Risk in the Urban Northeast (CCRUN) for the past five years to serve stakeholder needs in assessing and managing risks from climate variability and change. When Hurricane Sandy struck, we were in an ideal position, making flood forecasts and communicating NOAA forecasts to the public with dozens of media placements, translating the poorly understood flood forecasts into human dimensions. In 2013 and 2015, by request of New York City (NYC), we worked through the NYC Panel on Climate Change to deliver updated climate risk assessment reports, to be used in the post-Sandy rebuilding and resiliency efforts. These utilized innovative methodologies for probabilistic local and regional sea level change projections, and contrasted methods of dynamic versus (the more common) static flood mapping. We participated in a federal-academic partnership that developed a Sea Level Tool for Sandy Recovery that integrates CCRUN sea level rise projections with policy-relevant FEMA flood maps, and now several updated flood maps and coastal flood mapping tools (NOAA, FEMA, and USACE) incorporate our projections. For the adaptation response, we helped develop NYC's $20 billion flood adaptation plan, and we were on a winning team under the Housing and Urban Development Rebuild By Design (RBD) competition, a few of the many opportunities that arose with negligible additional funding and which CCRUN funds supported. Our work at times disrupted standard lines of thinking, but NYC showed an openness to altering course. In one case we showed that an NYC plan of wetland restoration in Jamaica Bay would provide no reduction in flooding unless deep-dredged channels circumventing them were shallowed or narrowed. In another, the lead author's RBD team challenged the notion at one location that levees were the solution to accelerating sea level rise, developing a plan to use ecological breakwaters and layered components of

  19. Unlocking the secrets of Al-tobermorite in Roman seawater concrete

    KAUST Repository

    Jackson, Marie D.

    2013-10-01

    Ancient Roman syntheses of Al-tobermorite in a 2000-year-old concrete block submerged in the Bay of Pozzuoli (Baianus Sinus), near Naples, have unique aluminum-rich and silica-poor compositions relative to hydrothermal geological occurrences. In relict lime clasts, the crystals have calcium contents that are similar to ideal tobermorite, 33 to 35 wt%, but the low-silica contents, 39 to 40 wt%, reflect Al3+ substitution for Si4+ in Q 2(1Al), Q3(1Al), and Q3(2 Al) tetrahedral chain and branching sites. The Al-tobermorite has a double silicate chain structure with long chain lengths in the b [020] crystallographic direction, and wide interlayer spacing, 11.49 Å. Na+ and K+ partially balance Al3+ substitution for Si4+. Poorly crystalline calcium-aluminum-silicate-hydrate (C-A-S-H) cementitious binder in the dissolved perimeter of relict lime clasts has Ca/(Si+Al) = 0.79, nearly identical to the Al-tobermorite, but nanoscale heterogeneities with aluminum in both tetrahedral and octahedral coordination. The concrete is about 45 vol% glassy zeolitic tuff and 55 vol% hydrated lime-volcanic ash mortar; lime formed <10 wt% of the mix. Trace element studies confirm that the pyroclastic rock comes from Flegrean Fields volcanic district, as described in ancient Roman texts. An adiabatic thermal model of the 10 m2 by 5.7 m thick Baianus Sinus breakwater from heat evolved through hydration of lime and formation of C-A-S-H suggests maximum temperatures of 85 to 97 °C. Cooling to seawater temperatures occurred in two years. These elevated temperatures and the mineralizing effects of sea-water and alkali- and alumina-rich volcanic ash appear to be critical to Al-tobermorite crystallization. The long-term stability of the Al-tobermorite provides a valuable context to improve future syntheses in innovative concretes with advanced properties using volcanic pozzolans.

  20. Integrated protecting plan for beach erosion. A case study in Plaka beach, E. Crete, Greece

    Science.gov (United States)

    Petrakis, Stelios; Alexandrakis, George; Kozyrakis, George; Hatziyanni, Eleni; Kampanis, Nikolaos

    2015-04-01

    Coastal zones are among the most active areas on Earth, being subjected to extreme wind / wave conditions, thus vulnerable to erosion. In Greece and Crete in particular, beach zones are extremely important for the welfare of the inhabitants, since, apart for the important biological and archaeological value of the beach zones, the socio-economic value is critical since a great number of human activities are concentrated in such areas (touristic facilities, fishing harbors etc.). The present study investigates the erosional procedures observed in Plaka beach, E. Crete, Greece, a highly touristic developed area with great archaeological interest and proposes a cost-effective solution. The factors taken into consideration for the proposed solution in reducing the erosion of the beach were the study of the climatological, geological and geomorphological regime of the area, the recent (~70 years) shifting of the coastline through the study of topographic maps, aerial photographs and satellite images, the creation of detailed bathymetric and seabed classification maps of the area and finally, a risk analysis in terms of erosional phenomena. On the basis of the above, it is concluded that the area under investigation is subjected to an erosional rate of about 1 m/10 years and the total land-loss for the past 70 years is about 4600 m2. Through the simulation of the wave regime we studied 3 possible scenarios, the "do-nothing" scenario, the construction of a detached submerged breakwater at the depth of 3 meters and, finally, the armoring of the existing beach-wall through the placement of appropriate size and material boulders, forming an artificial slope for the reducing of the wave breaking energy and a small scale nourishment plan. As a result, through the modeling of the above, the most appropriate and cost-effective solution was found to be the third, armoring of the existing coastal wall and nourishment of the beach periodically, thus the further undermining of the

  1. Living shorelines can enhance the nursery role of threatened estuarine habitats.

    Science.gov (United States)

    Gittman, Rachel K; Peterson, Charles H; Currin, Carolyn A; Fodrie, F Joel; Piehler, Michael F; Bruno, John F

    2016-01-01

    Coastal ecosystems provide numerous services, such as nutrient cycling, climate change amelioration, and habitat provision for commercially valuable organisms. Ecosystem functions and processes are modified by human activities locally and globally, with degradation of coastal ecosystems by development and climate change occurring at unprecedented rates. The demand for coastal defense strategies against storms and sea-level rise has increased with human population growth and development along coastlines world-wide, even while that population growth has reduced natural buffering of shorelines. Shoreline hardening, a common coastal defense strategy that includes the use of seawalls and bulkheads (vertical walls constructed of concrete, wood, vinyl, or steel), is resulting in a "coastal squeeze" on estuarine habitats. In contrast to hardening, living shorelines, which range from vegetation plantings to a combination of hard structures and plantings, can be deployed to restore or enhance multiple ecosystem services normally delivered by naturally vegetated shores. Although hundreds of living shoreline projects have been implemented in the United States alone, few studies have evaluated their effectiveness in sustaining or enhancing ecosystem services relative to naturally vegetated shorelines and hardened shorelines. We quantified the effectiveness of (1) sills with landward marsh (a type of living shoreline that combines marsh plantings with an offshore low-profile breakwater), (2) natural salt marsh shorelines (control marshes), and (3) unvegetated bulkheaded shores in providing habitat for fish and crustaceans (nekton). Sills supported higher abundances and species diversity of fishes than unvegetated habitat adjacent to bulkheads, and even control marshes. Sills also supported higher cover of filter-feeding bivalves (a food resource and refuge habitat for nekton) than bulkheads or control marshes. These ecosystem-service enhancements were detected on shores with

  2. Investigation and discussion of marine structures integrated with ocean energy devices%海工构筑物海洋能集成利用技术探讨

    Institute of Scientific and Technical Information of China (English)

    王树杰; 王举田; 刘锦昆; 袁鹏; 刘臻; 徐志刚; 季文峰

    2015-01-01

    将海工构筑物作为海洋能获能装置的安装载体可大幅降低海洋能发电的成本,同时,海工构筑物等海上设施客观上存在利用海洋能实现能量供应的需求,因此海洋能发电装置与海工构筑物相互结合具有良好的综合效益,将是未来海洋能利用的一个发展方向。针对波浪能和潮流能两种海洋能发电方式,分别对柔性叶片潮流能水轮机与进海路集成利用技术;垂直轴和水平轴潮流能水轮机以及振荡浮子式波能装置与导管架石油平台集成利用技术;OWC波能装置与沉箱防波堤集成利用技术进行了探讨,并提出海工构筑物海洋能集成利用技术中需要解决的几点问题。%Ocean energy devices installed on marine structures can greatly reduce the cost of ocean energy power generation. On the other hand, marine structures such as offshore installations need to gain power generated by ocean energy nearby. Therefore, marine structures equipped with ocean energy devices have comprehensive benefits, which will be developed in the future. According to the classification of ocean energy power generation utilizing wave and tidal current, some types of integrated utilization are investigated and discussed, such as flexible tidal current turbines integrated with perforated sea roads, vertical and horizontal tidal current turbines integrated with jacket platforms, oscillating buoys integrated with jacket platforms and OWC wave energy devices integrated with caisson breakwaters. At the same time, some questions and suggestions are put forward in order to make the utilization mature.

  3. Hazard Assessment and Early Warning of Tsunamis: Lessons from the 2011 Tohoku earthquake

    Science.gov (United States)

    Satake, K.

    2012-12-01

    . Tsunami hazard assessments or long-term forecast of earthquakes have not considered such a triggering or simultaneous occurrence of different types of earthquakes. The large tsunami at the Fukushima nuclear power station was due to the combination of the deep and shallow slip. Disaster prevention for low-frequency but large-scale hazard must be considered. The Japanese government established a general policy to for two levels: L1 and L2. The L2 tsunamis are the largest possible tsunamis with low frequency of occurrence, but cause devastating disaster once they occur. For such events, saving people's lives is the first priority and soft measures such as tsunami hazard maps, evacuation facilities or disaster education will be prepared. The L1 tsunamis are expected to occur more frequently, typically once in a few decades, for which hard countermeasures such as breakwater must be prepared to protect lives and properties of residents as well as economic and industrial activities.

  4. Adapting coastal structures to a moving relative sea level: Roman Time geoarchaeological evidence from Posillipo promontory (Naples, Italy).

    Science.gov (United States)

    Aucelli, Pietro; Cinque, Aldo; Giordano, Francesco; Mattei, Gaia; Pappone, Gerardo; Rizzo, Angela

    2016-04-01

    The Posillipo promontory belongs to the southern periphery the active volcanic complex called Campi Flegrei. Especially the central caldera of CF is well known for offering a rich geoarchaeological record of the vertical ground movements it has been suffering since Roman times; which includes the ruins of Portus Julius (built in 37 BC) presently found between 10 and 5 m bsl and the Middle Ages Lithophaga perforations at about 7m asl on the marble columns of the Serapeo building (Morhange, 2006 and references therein). In order to better constraint the vertical movements suffered by the Posillipo promontory during the last two millennia, we selected three geoarcaeolgical coastal sites (Nisida Roman port, Marechiaro Roman port and Villa Robery) and we studied them by means of both geomorphological observations and geophysical surveys (Side Scan Sonar and Single Beam echo-sounder). Within the submerged Roman port of Nisida, built in the 1st AD, we found two pilae of the ancient pier. The submersion measuring of the well-preserved one provided a palaeo-sea level at 3.1±0.30 m bsl. In the submerged Roman port of Marechiaro, we recognized a still preserved breakwater connected to the tuffaceous sea cliff, and submerged foundations of a 1st century small sea-side villa. Nearby there is also a two-storeyed Roman building (Palazzo degli Spiriti), built in the 1st cent. BC and later restructured to adapt to a phase of subsidence (Gunther 1908). From our submersion measurements, two different paleo-sea levels can be deduced: one for the 1st cent. BC at -4.4 + -0.50 m and another for the 1st cent. AD at -3 + - 0.30 m. Finally, in front of the modern Villa Rosebery the sea bottom shows a sub-horizontal element at -3m to -3.5m bsl, emerged during the 1st BC century. In fact, at least three houses were erected there during said century (Gunther, 1908). As the area was very little elevated, an alignment of pilae was also constructed to protect those houses from the breakers. By

  5. Assessment of tsunami resilience of Haydarpaşa Port in the Sea of Marmara by high-resolution numerical modeling

    Science.gov (United States)

    Aytore, Betul; Yalciner, Ahmet Cevdet; Zaytsev, Andrey; Cankaya, Zeynep Ceren; Suzen, Mehmet Lütfi

    2016-08-01

    domains in 3-m and 1-m resolutions and the water elevations computed from the previous simulations were inputted from the border of the large domain. A tsunami numerical code, NAMI DANCE, was used in the simulations. The tsunami parameters in the highest resolution were computed in and around the port. The effect of the data resolution on the computed results has been presented. The performance of the port structures and possible effects of tsunami on port operations have been discussed. Since the harbor protection structures have not been designed to withstand tsunamis, the breakwaters' stability becomes one of the major concerns for less agitation and inundation under tsunami in Haydarpaşa Port for resilience. The flow depth, momentum fluxes, and current pattern are the other concerns that cause unexpected circulations and uncontrolled movements of objects on land and vessels in the sea.

  6. Ampliación del puerto Lyttelton. Nueva Zelanda

    Directory of Open Access Journals (Sweden)

    Editorial, Equipo

    1965-05-01

    Full Text Available Lyttleton Port Authority has drawn up a project for the reform and construction of new wharves and breakwaters, to cater for the increasing sea traffic. The cost of the project is 4.5 million pounds. The main work consists of a 1,070 m long front wharf, built in deep water, and apt for use by large ships. The structure of the wharf consists of a filled in zone, taken from the sea, along the edge of which a row of piles has been arranged, to support the wharf itself. This has been made with hard Australian timber. But the platform over the filled in zone is built with soft local timber. The hills rising along the coastline have been traversed by two tunnels: one for the roadway and the other to take the railway. These communication lines, which save 11 km, will link the harbour with Christchurch, the most important city in South Island. The bottom, where the wharf has been made, was soft mud, awkward to contain and control. To overcome this difficulty a simple and ingenious method was adopted. Loads of stone, from nearby quarry residues, were thrown into the mud. The stones pushed out the mud in the manner of a wavefront. The mud was then dredged away, and the stone filling operation was continued. Stone had to be used as there was insufficient sand in the neighbourhood.La Junta de Obras del puerto de Lyttelton (Nueva Zelanda ha redactado un proyecto de reforma y construcción de nuevos muelles y rompeolas para absorber el creciente movimiento portuario, cuyo coste se eleva a 4,5 millones de libras. La obra consiste en un muelle frontal, continuo, de 1.070 m de longitud, en zona de gran calado, capaz para que atraquen barcos de gran tonelaje. La estructura está constituida por una zona de rellenos, ganados al mar, en cuyo frente se hallan unas filas de pilotes sobre los que descansa la estructura del muelle, construida a base de madera dura australiana; en cambio, la plataforma formada sobre el relleno es de madera blanda del país. Los montes

  7. Case study of small harbor excitation under storm and tsunami conditions

    Science.gov (United States)

    Synolakis, Costas; Maravelakis, Nikos; Kalligeris, Nikos; Skanavis, Vassilios; Kanoglu, Utku; Yalciner, Ahmet; Lynett, Pat

    2016-04-01

    Simultaneous nearshore and interior-to-ports wave and current measurements for small ports are not common, and few, if any, benchmarking cases at sufficient resolution exist to help validate numerical model of intermediate waves, or even long waves. The wave conditions inside the old Venetian harbor of Chania, Greece and offshore were measured and studied from 2012 to 2015. The construction of this harbor began in the 14th century, and since then, its layout has been modified to adapt to different social and to economic conditions. It is divided into a western and an eastern basin. The eastern basin is used by recreational vessels and fishing boats throughout the year. The western basin has an exposed entrance to the north, and it is essentially functional half of the year, because of the severe overtopping and flooding that occur during the northern winter storms. Our work is motivated by the necessity to protect the monument from severe winter storm conditions and allow safe mooring and all other recreational activities that take place in the exposed western basin. Two earlier studies had proposed the construction of a low crested breakwater near the harbor entrance. The first design has been partially constructed, while the second never materialized. The main disadvantage of both studies was the lack of any wave field measurements. At the same time, second order or complimentary phenomena such as harbor resonance had not been considered. To address the lack of field data, the offshore wave climate has been monitored since October 2012 using an AWAC 600kHz instrument, deployed at 23m depth. The response of the western and eastern basins of the harbor was measured with a TWR-2050 (deployed at 5.5m depth) and an RBRDuet T.D./wave (deployed at 2m depth) pressure gauges respectively. Significant wave heights ranging up to 5.8 m with significant periods of up to 10 sec were measured. The harbor pressure gauges are now being re-deployed in other locations to collect

  8. Tsunami vulnerability and damage for buildings analyzed by means of two methods (PTVA-3 and SCHEMA) in the area of Augusta and Siracusa, eastern Sicily, Italy

    Science.gov (United States)

    Pagnoni, Gianluca; Tinti, Stefano

    2015-04-01

    The coast of the eastern Sicily is exposed to tsunamis that can be generated by local earthquakes (e.g. the 1169, 1693, 1908 events) and by earthquakes located in distant seismic zones (see the 365 AD tsunamigenic quake in Western Hellenic Arc). Tsunamis can also be generated by landslides possibly triggered by earthquakes. The Hyblean-Malta steep escarpment running offshore at a small angle with the coast is an ideal place for submarine mass failure occurrences with tsunamigenic effects. The entire eastern coast of Sicily from Messina in the north to Siracusa in the south is under the threat of tsunamis. In the frame of the FP7 European project ASTARTE (Assessment, Strategy And Risk Reduction for Tsunamis in Europe - FP7-ENV2013 6.4-3, Grant 603839), the segment of coast from Augusta to Siracusa was selected to undertake specific and detailed studies of tsunami hazard, vulnerability and damage to test existing methods and develop innovative approaches. The scope of the present work regards vulnerability and damage analyses. We chose to adopt two methods, known in the literature and briefly denoted as PTVA-3 and SCHEMA, that are based on two very different approaches, the former more qualitative and the latter more quantitative. The method PTVA-3 determines the vulnerability and damageability of a building by weighting and ranking a number of attributes covering the structural features of the edifice and the relevant characteristics of the surrounding environment such as the position with respect to the coast, the existence of defensive elements (e.g. walls, breakwaters, vegetation) and also the proximity to potential sources of floating objects that can feed damaging debris flows. On the other hand, the SCHEMA method uses a classification of building and a damage matrix that were derived from experimental fragility and damage curves first established after the Sumatra 2004 tsunami and later refined and adapted to the building stock of the Mediterranean region. The

  9. A Powerful Method of Measuring Sea Wave Spectra and their Direction

    Science.gov (United States)

    Blasi, Christoph; Mai, Stephan; Wilhelmi, Jens; Zenz, Theodor; Barjenbruch, Ulrich

    2014-05-01

    Besides the need of precise measurements of water levels of the sea, there is an increasing demand for assessing waves in height and direction for different purposes like sea-wave modelling and coastal engineering. The design of coastal structures such as piles, breakwaters, and offshore structures like wind farms must take account of the direction of the impacting waves. To date, records of wave directions are scarce. The reason for this might be the high costs of purchasing and operating such measuring devices. These are usually buoys, which require regular maintenance. Against this background, the German Federal Institute of Hydrology (BfG) developed a low-cost directional sea-wave monitoring system that is based on commercially available liquid-level radar sensors. These sensors have the advantage that they have no contact to the fluid, i.e. the corrosive sea water. The newly developed device was tested on two sites. One is the tide gauge 'Borkum Südstrand' that is located in the southern North Sea off the island of Borkum. The other one is the 'Research Platform FINO1' approximately 45 km north of the island of Borkum. The main focus of these tests is the comparison of the data measured by the radar-based system with those of a conventional Directional Wave Rider Buoy. The general conditions at the testing sites are good for the tests. At the tide gauge 'Borkum Südstrand' waves propagate in different directions, strongly influenced by the morphological conditions like shallow waters of the Wadden Seas and the coast of the island of Borkum. Whereas on the open sea, at the site FINO1, the full physical conditions of the sea state, like heavy storms etc. play an important role. To determine and measure the direction of waves, the device has to be able to assess the wave movements in two dimensions. Therefore, an array of several radar sensors is required. Radar sensors are widely used and well established in measuring water levels, e.g. in tanks and basins

  10. Multicriteria analysis to evaluate wave energy converters based on their environmental impact: an Italian case study

    Science.gov (United States)

    Azzellino, Arianna; Contestabile, Pasquale; Lanfredi, Caterina; Vicinanza, Diego

    2010-05-01

    The exploitation of renewable energy resources is fast becoming a key objective in many countries. Countries with coastlines have particularly valuable renewable energy resources in the form of tides, currents, waves and offshore wind. Due to the visual impact of siting large numbers of energy generating devices (eg. wind turbines) in terrestrial landscapes, considerable attention is now being directed towards coastal waters. Due to their environmental sensitivity, the selection of the most adequate location for these systems is a critical factor. Multi-criteria analysis allows to consider a wide variety of key characteristics (e.g. water depth, distance to shore, distance to the electric grid in land, geology, environmental impact) that may be converted into a numerical index of suitability for different WEC devices to different locations. So identifying the best alternative between an offshore or a onshore device may be specifically treated as a multicriteria problem. Special enphasisi should be given in the multicriteria analysis to the environmental impact issues. The wave energy prospective in the Italian seas is relatively low if compared to the other European countries faced to the ocean. Based on the wave climate, the Alghero site, (NW Sardinia, Italy) is one of the most interesting sites for the wave energy perspective (about 10 kW/m). Alghero site is characterized by a high level of marine biodiversity. In 2002 the area northern to Alghero harbour (Capo Caccia-Isola Piana) was established a Marine Protected Area (MPA). It could be discussed for this site how to choose between the onshore/offshore WEC alternative. An offshore device like Wave Dragon (http://www.wavedragon.net/) installed at -65m depth (width=300m and length=170 m) may approximately produce about 3.6 GWh/y with a total cost of about 9,000,000 €. On the other hand, an onshore device like SSG (http://waveenergy.no/), employed as crown wall for a vertical breakwater to enlarge the present

  11. Al-tobermorite in Pyroclastic Rock-Seawater Environments: 1963-1967 Surtsey Tephra and 2000-year-old Roman Baianus Sinus Harbor Concrete

    Science.gov (United States)

    Jackson, M. D.; Moore, J. G.; Wenk, H.; Monteiro, P. J.

    2012-12-01

    Interaction of basaltic tephra from the 1963-1967 Surtsey eruptions in Iceland with 70-150 °C seawater produced authigenic zeolites and Al-tobermorite, a layered calcium-aluminum-silicate-hydrate mineral that holds promise as a cementitious binder for environmentally-friendly concretes and concrete encapsulations of hazardous wastes, but has never been recognized in conventional portland cement concretes. A Roman concrete breakwater, or pilae, constructed of lime and Campi Flegrei pyroclastic rock in the 14-26°C seawater of Pozzuoli Bay (Baianus Sinus) in first century BCE, however, developed Al-tobermorite in relict lime clasts, Neapolitan Yellow Tuff pumice fragments, and voids, forming about 5-10 volume% of the pozzolanic mortar. A thermal model of the 10m2 by 6m tall pilae indicates that exothermic hydration of portlandite and poorly-crystalline calcium-aluminum-silicate-hydrate (C-A-S-H) cementitious binder produced maximum adiabatic temperatures calcium, with Al/(Si+Al)=0.16-0.17 and Ca/(Si+Al)=0.83. This is likely the result of saturation with respect to portlandite at pH>12.7, and high Al3+mobility in a system infused with silicon, aluminum, sodium and potassium from the alkali-rich Flegrean ash, with sulfate and chloride from seawater acting as possible mineralizers. Synchrotron-radiation soft X-ray microscopy and NMR studies indicate that Baianus Sinus Al-tobermorite has a double-silicate-chain structure with aluminum substitution for silicon in tetrahedral chain and branching sites, and a large 11.44(3) Å interlayer spacing. The bulk modulus measured from high pressure synchroton X-ray diffraction experiments, 54.7±5.5 GPa, is ~20 GPa greater than modern C-A-S-H. Na2O and K2O at 0.3-1.2 weight% partially balance Al3+ substitution for Si4+ in both the Surtsey and Baianus Sinus crystals. Sulphate and chloride from seawater were sequestered in anhydrite and gypsum in Surtsey tephra, and in discrete ettringite and hydrocalumite microstructures in the

  12. Characterization of Mineral Assemblages in Ancient Roman Maritime Concrete with Synchrotron X-ray Techniques

    Science.gov (United States)

    Meral, C.; Jackson, M. D.; Monteiro, P. J.; Wenk, H.

    2012-12-01

    Romans used lime and aluminosilicate-rich volcanic ash to bind tuff aggregates in concrete structures that have remained durable for 2000 years. A major accomplishment of Roman engineers was to construct enduring coastal underwater structures in seawater, which were important to long-distance trade and military endeavors. Two millennia later, the reasons for the extraordinary durability of the maritime structures remain enigmatic. The concretes are highly complex composites composed of relict lime, tuff and pumice clasts and pozzolanic reaction products. Calcium-chloroaluminates and sulfoaluminates occur in certain relict voids. Further understanding of their mineralogical components would provide guidelines in designing future structures. Here, we use synchroton radiation applications to characterize certain phases within a Roman maritime mortar specimen from a breakwater in Pozzuoli Bay, Baianus Sinus, near Naples. We performed X-ray computed micro-tomography (μ-XCT) at beamline 8.3.2 of the Advanced Light Source (ALS) at Lawrence Berkeley Laboratories to segment the complex composite without damaging the specimen. We isolated certain relict sub-spherical voids and illustrated crystal morphologies with 3-D reconstructions. We then used beamline 12.3.2 at the ALS to provide highly accurate identifications of diverse crystal phases in various mortar components - relict lime clasts, tuff or pumice clasts, cementitious matrix and relict voids - in sites previously identified and characterized with petrogaphic techniques. X-ray micro-fluorescence (μ-XRF) mapping provided calcium and iron maps of the sites, which were useful in selecting fine-scale areas for scanning transmission X-ray micro-diffraction (μ-XRD) mapping at high spatial resolution, about 1 micron. The μ-XRD analyses utilized both monochromatic and polychromatic light measurements. Polychromatic light was more appropriate for phases with grain sizes larger than the doubly focused X-ray beam, about 1 x

  13. 风暴潮对广东省沿海港航设施影响及防护对策研究%Effect of Storm Surge on Port Facilities in the Guangdong Coastal Area and Its Protection Strategies

    Institute of Scientific and Technical Information of China (English)

    贾良文; 谢凌峰; 罗敬思; 徐治中; 龚文平

    2012-01-01

    The effect of storm surge on port facilities and its characteristics are primarily studied based on field investigations and historical records in the Guangdong coastal area, and the some corresponding protection strategies have been suggested. The main characteristics of the damages caused by storm surge include the most serious damage of breakwaters, the frequent occurrence of damage during the construction period, the retaining embankment damage now and then, the seldom damage of structures of the large wharfs and the often damage of structures of the small to middle wharfs, especially the fishing ports. The main reasons for these damages are the lack of wave data, the low of designed wave height and the small of armor block. The protection strategies have been proposed in the aspects of techniques, engineering and management. In the aspect of techniques, strengthening the wave observations and researches and improving the calculation method for designing the wave height are suggested. For engineering, it is suggested to improve the wave height design and armor block standards and the plan configuration, to shorten the construction period with no protection, to construct safe islands and risk avoidance regions, to enhance the investigation, check and analysis of the existing port facilities and to take the pertinent reinforcements. For the management, to establish an early warning and forecasting system for storm surge, to set up an emergency plan and to enhance the maintenance of port facilities are recommended.%通过实地调研,结合历史记录资料,初步研究了风暴潮对广东省沿海港航设施的影响状况和特点,提出了相应的防护措施。研究发现,广东省沿海港口设施受风暴潮影响的主要特点为防波堤受损最为严重,施工期受风暴潮影响损坏普遍存在,码头护岸受损较普遍,大型码头结构受损较少,中、小型码头结构特别是渔港结构受损较多。损坏成因主

  14. Analysis of X-band radar images for the detection of the reflected and diffracted waves in coastal zones

    Science.gov (United States)

    Ludeno, Giovanni; Natale, Antonio; Soldovieri, Francesco; Vicinanza, Diego; Serafino, Francesco

    2014-05-01

    The observation of nearshore waves and the knowledge of the sea state parameters can play a crucial role for the safety of harbors and ocean engineering. In the last two decades, different algorithms for the estimation of sea state parameters, surface currents and bathymetry from X-band radar data have been developed and validated [1, 2]. The retrieval of ocean wave parameters such as significant height, period, direction and wavelength of the dominant wave is based on the spectral analysis of data sequences collected by nautical X-band radars [3]. In particular, the reconstruction of the wave motion is carried out through the inversion procedure explained in [1-3], which exploits the dispersion relationship to define a band pass filter used to separate the energy associated with the ocean waves from the background noise. It is worth to note that the shape of such a band pass filter depends upon the value of both the surface currents and bathymetry; in our reconstruction algorithm these parameters are estimated through the (Normalized Scalar Product) procedure [1], which outperforms other existing methods (e.g., the Least Squares) [4]. From the reconstructed wave elevation sequences we can get the directional spectrum that provides useful information (i.e., wavelength, period, direction and amplitude) relevant to the main waves contributing to the wave motion. Of course, in coastal zones a number of diffraction and reflection phenomena can be observed, due to sea-waves impinging obstacles as jetties, breakwaters and boats. In the present paper we want to show the capability to detect reflected and diffracted sea-waves offered by the processing of X-band radar data. Further details relevant to the obtained results will be provided in the full paper and at the conference time. References [1] F. Serafino, C. Lugni, F. Soldovieri, "A novel strategy for the surface current determination from marine X-Band radar data", IEEE Geosci. and Remote Sensing Letters, vol. 7, no

  15. California State Waters Map Series--Hueneme Canyon and vicinity, California

    Science.gov (United States)

    Johnson, Samuel Y.; Dartnell, Peter; Cochrane, Guy R.; Golden, Nadine E.; Phillips, Eleyne L.; Ritchie, Andrew C.; Kvitek, Rikk G.; Greene, H. Gary; Krigsman, Lisa M.; Endris, Charles A.; Clahan, Kevin B.; Sliter, Ray W.; Wong, Florence L.; Yoklavich, Mary M.; Normark, William R.

    2012-01-01

    of three smaller, unnamed headless canyons incised into the shelf southeast of Hueneme Canyon. The shelf is underlain by tens of meters of interbedded upper Quaternary shelf, estuarine, and fluvial deposits that formed as sea level fluctuated in the last several hundred thousand years. Hueneme Canyon extends about 15 km offshore from its canyon head near the dredged navigation channel of the Port of Hueneme. The canyon is relatively deep (about 150 m at the California's State Waters limit) and steep (canyon flanks as steep as 25° to 30°). Historically, Hueneme Canyon functioned as the eastern termination of the Santa Barbara littoral cell by trapping all eastward littoral drift, not only feeding the large Hueneme submarine fan but acting as the major conduit of sediment to the deep Santa Monica Basin; however, recent dredging programs needed to maintain Channel Islands Harbor and the Port of Hueneme have moved the nearshore sediment trapped by jetties and breakwaters to an area southeast of the Hueneme Canyon head. Seafloor habitats in the broad Santa Barbara Channel region consist of significant amounts of soft sediment and isolated areas of rocky habitat that support kelp-forest communities nearshore and rocky-reef communities in deep water. The potential marine benthic habitat types mapped in the Hueneme Canyon and vicinity map area are related directly to the geomorphology and sedimentary processes that are the result of its Quaternary geologic history. The two basic megahabitats in the map area are Shelf (continental shelf) and Flank (continental slope). The flat seafloor of the continental shelf in the Hueneme Canyon and vicinity map area is dynamic, as indicated by mobile sand sheets and coarser grained scour depressions. The active Hueneme Canyon provides considerable relief to the continental shelf in the map area, and its irregular morphology of eroded walls, landslide scarps, and deposits and gullies provide promising habitat for groundfish, crabs

  16. California State Waters Map Series: offshore of Santa Barbara, California

    Science.gov (United States)

    Johnson, Samuel Y.; Dartnell, Peter; Cochrane, Guy R.; Golden, Nadine E.; Phillips, Eleyne L.; Ritchie, Andrew C.; Greene, H. Gary; Krigsman, Lisa M.; Kvitek, Rikk G.; Dieter, Bryan E.; Endris, Charles A.; Seitz, Gordon G.; Sliter, Ray W.; Erdey, Mercedes D.; Gutierrez, Carlos I.; Wong, Florence L.; Yoklavich, Mary M.; Draut, Amy E.; Hart, Patrick E.; Conrad, James E.; Cochran, Susan A.; Johnson, Samuel Y.; Cochran, Susan A.

    2013-01-01

    utilized Santa Barbara coastal zone, including Arroyo Burro Beach Park, Leadbetter Beach, East Beach, and “Butterfly Beach.” There are ongoing coastal erosion problems associated with both development and natural processes; between 1933–1934 and 1998, cliff erosion in the map area occurred at rates of about 0.1 to 1 m/yr, the largest amount (63 m) occurring at Arroyo Burro in the western part of the map area. In addition, development of the Santa Barbara Harbor, which began in 1928, lead to shoaling west of the harbor as the initial breakwater trapped sand, as well as to coastal erosion east of the harbor. Since 1959, annual harbor dredging has mitigated at least some of the downcoast erosion problems. The Offshore of Santa Barbara map area lies in the central part of the Santa Barbara littoral cell, which is characterized by littoral drift to the east-southeast. Drift rates have been estimated to be about 400,000 tons/yr at Santa Barbara Harbor. Sediment supply to the western and central parts of the littoral cell, including the map area, is largely from relatively small transverse coastal watersheds. Within the map area, these coastal watersheds include (from east to west) San Ysidro Creek, Oak Creek, Montecito Creek, Sycamore Creek, Mission Creek, Arroyo Burro, and Atascadero Creek. The Ventura and Santa Clara Rivers, the mouths of which are about 40 to 50 km southeast of Santa Barbara, are much larger sediment sources. Still farther east, eastward-moving sediment in the littoral cell is trapped by Hueneme and Mugu Canyons and then transported to the deep-water Santa Monica Basin. The offshore part of the map area consists of a relatively flat and shallow continental shelf, which dips gently seaward (about 0.4° to 0.8°) so that water depths at the 3-nautical-mile limit of California’s State Waters are about 45 m in the east and about 75 m in the west. This part of the Santa Barbara Channel is relatively well protected from large Pacific swells from the north

  17. Discussion on Japan’s Attitude toward the Territory after World War II and Okinawa under U.S Trust%试论二战后日本在领土处理问题上的态度与美国托管冲绳(一)

    Institute of Scientific and Technical Information of China (English)

    安成日; 李金波

    2013-01-01

    To Japan who was stopped exercising a state sovereignty after being defeated, realizing peace-making, ending the occupation as soon as possible, resuming the exercise of sovereignty and rejoining the international community were the most important diplomatic topics in the early days of postwar. In this process, how to minimize the cost, use the most advantageous way to make peace had become the concern of all sectors of the Japanese society. However, when to make peace and what were put in the peace treaty depended on countries winning the war. After World War II, US-Soviet Union contradiction became inten-sified, and the dark clouds of the Cold War spread in East Asia; the USA who had the dominant right over the occupation of Japan, in order to make Japan an”East Asia breakwater against the Communist”, singed a ”lenient peacemaking” over Japan, increasing the opportunities that Japan could join the discussion of peacemaking abruptly. Under the situation of a rapid spreading of the Cold War, security issues associated with the disposal problems of surrounding islands of Japan became the key to making peace with the allies. Finally, Shigeru Yoshida government accepted the continuation of deployment of U.S army and agreed U.S to trust Okinawa in the name of the United Nations by sacrificing the interests of the people in Okinawa, and in the way of retaining the potential sovereignty (or ’residual sovereignty’), and limited restoration of sovereignty to realize the peacemaking with the majority of western camp, that is, a de facto”one-sided peacemaking”.%  对战败以后被停止行使国家主权的日本来说,尽快实现媾和结束占领,恢复行使国家主权,重返国际社会是战后初期最重要的外交课题。在这一过程中,如何以最小的代价,以对己最有利的方式实现媾和成为日本各界关注的焦点。然而,一般来说何时媾和,把何种问题纳入媾和议题等均由掌握媾和主