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1
Pillai, Karthika. "Wave overtopping at berm breakwaters: Development of prediction formula and a study on the impact of sea level rise on the overtopping rate." Thesis, Griffith University, 2018. http://hdl.handle.net/10072/377582.
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Ports and harbours are often protected from violent waves by rubble mound breakwaters. Among the diverse types of rubble mound breakwater structures, berm breakwaters are relatively new, having been introduced in the early 1980s. In general, their construction ensures maximum quarry utilization and they can be built using smaller construction equipment. This reduces the overall cost and opens opportunities for local contractors.
The wave induced overtopping rate is often considered a measure of safety of coastal structures with sea level rise, caused by global climate change, increasing the frequency and intensity of wave overtopping of these structures. Hence, the mean wave overtopping rate, and how it may change over time, is a key factor to be considered in the design of berm breakwaters. As a result of this, the wave overtopping rate has been extensively studied in the past decade. However, few studies focus on the overtopping behaviour of hardly/partly reshaping berm breakwaters. Additionally, a simpler and more accurate overtopping prediction tool, which includes the influence of the governing variables on the overtopping rate, is required for berm breakwaters.
Given the above, the primary aim of this research work was to assess the influence of the structural and hydraulic variables on the overtopping rate at hardly/partly reshaping berm breakwaters through a series of laboratory tests. As a first step, the available prediction methods were reviewed in detail and a sensitivity analysis was performed to understand the influence of the governing variables in estimating the overtopping rate at berm breakwaters. In addition, a detailed analysis of data used to develop the models were conducted to understand their applicability. Then, the existing small-scale physical model test data were collected from previous research and was analysed comprehensively. The resultant database represented mostly a fully reshaping condition with limited tests on hardly/partly reshaping berm breakwaters. Hence, physical model tests were conducted (as part of this research) to remove the paucity of data in the existing databases. The new data represented overtopping from a wider range of tested wave steepness, berm width, berm level and crest level for the hardly/partly reshaping structures. The existing and new data were combined to develop a comprehensive overtopping database with 701 data.
The second phase of the research focussed on the development of the empirical prediction formula to estimate the wave overtopping rate of berm breakwaters. The sensitivity analysis showed that there were significant inconsistencies among the available models in determining the influence of the variables on the estimated overtopping rate. To overcome these deficiencies/inconsistencies, and with a view to develop a universal prediction model for berm breakwaters, a new empirical formula was proposed using the comprehensive database (created as part of this research). In order to establish the new formula, the model tree approach of data mining was utilized and dimensionless parameters were used to develop the model to generalise the results. Then, the performance of the developed model was compared with other existing, and more complex, prediction models. The accuracy measures such as RMSE and Bias showed that the new formula was more accurate than the existing prediction methods. In short, the developed formula provides physically sound influences of the governing parameters on the overtopping rate and therefore it can be used as a robust tool for engineers in the design of berm breakwaters.
Another issue that now must be considered in the design of coastal structures is the effect of climate change. Coastal structures, including berm breakwaters, are increasingly at risk of excessive overtopping due to climate change effects such as sea level rise (SLR). SLR needs to be considered in the safety assessment of existing and design of newly constructed berm breakwaters. Most of the existing literature is concentrated on the stability, increase in the run-up and overtopping failure of conventional rubble mound structures. Hence, as a capstone to this research, the influence of sea level rise on the overtopping rate of berm breakwaters was investigated. The newly developed formula was utilized for this investigation since it considers the influence of water depth better than the existing prediction models. The effect of SLR on the overtopping rate and the required upgradation of the structure were represented as functions of the relative change in water level. The results showed that overtopping increased exponentially in the shallow zone compared to that of the deep zone. The increase in the crest freeboard, required to maintain the design overtopping rate was estimated to be less than the increase needed compared to berm width for the different sea level rise scenarios considered. Furthermore, the required crest freeboard was influenced less by the initial configuration of the berm width.
Finally, in the last part of the research, the focus was extended on the probability of failure (in terms of the overtopping rate) and the optimum upgradation interval of berm breakwaters considering the influence of sea level rise during their service life. Optimum upgradation intervals were determined by minimising the cost of upgradation and failure. The results were further exemplified using the design parameters of the Sirevag berm breakwater in Norway. The outcome of the analysis could be used as a preliminary assessment of the upgradation measures to be adopted and requires detailed cost and feasibility studies. The outlined method can be used to quantitatively estimate the influence of the SLR on the overtopping rate and could also be included in the design philosophy of berm breakwaters.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Eng & Built Env
Science, Environment, Engineering and Technology
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2
Ye, Jianhong. "Numerical analysis of Wave-Seabed-Breakwater interactions." Thesis, University of Dundee, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.604579.
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3
Ariyarathne, Hanchapola Appuhamilage. "Efficiency of perforated breakwater and associated energy dissipation." Texas A&M University, 2007. http://hdl.handle.net/1969.1/85807.
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The flow field behavior in the vicinity of a perforated breakwater and the
efficiency of the breakwater under regular waves were studied.
To examine the efficiency of the structure thirteen types of regular wave
conditions with wave periods T = 1, 1.2, 1.6, 2, 2.5 sec and wave heights Hi = 2, 4, 6, 8,
10 cm in an intermediate water depth of 50 cm were tested. The incoming, reflected and
transmitted wave heights were measured using resistance type wave gauges positioned at
the required locations. The efficiency of the structure was calculated considering the
energy balance for the system. The efficiency of the structure for different wave
conditions and with different parameters are shown and compared.
Seven types of regular waves with wave periods T = 1, 1.6, 2, 2.5 sec and wave
heights Hi = 4, 6, 8, 10 cm in an intermediate water depth of 50 cm were tested for the
flow behavior study. In order to study the flow field variation with phase, ten phases
were considered per one wave. The Particle Image Velocimetry (PIV) technique was
employed to measure the two dimensional instantaneous velocity field distribution and
MPIV (Matlab toolbox for PIV) and DaVis (a commercial software) were used to calculate the velocity vectors. By repeating the experiments and taking an average, the
mean velocity field, mean vorticity field, mean turbulent intensity and mean turbulent
kinetic energy field were calculated for each phase and for each wave condition. The
phase average fields for each wave condition for each of the above mentioned
parameters were calculated taking the average of ten phases. The phase averaged
velocity, vorticity and turbulent kinetic energy fields are presented and compared. The
energy dissipation based on both elevation data and the velocity data are presented and
compared.
It was found that for more than 75% of the tested wave conditions, the energy
dissipation was above 69%. Thus the structure is very effective in energy dissipation.
Further it was found that for all the tested wave conditions most of the turbulent kinetic
energy form near the free surface and near the front wall, where as behind the back wall
of the structure the turbulent kinetic energy was very small.
4
Crawford, Adam Randolph. "Measurement and analysis of wave loading on a full scale coastal structure." Thesis, University of Plymouth, 1999. http://hdl.handle.net/10026.1/837.
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The aim of this investigation was to measure and analyse wave loading on a full scale coastal structure in order to validate current breakwater design methods and to improve understanding of the physical processes involved. A range of new, robust field measurement instrumentation was developed and deployed at the chosen field site, the Alderney Breakwater in the Channel Islands. The instrumentation deployed in this particularly harsh wave loading environment included an array of wave loading pressure sensors together with co-located void fraction gauges, which were used to measure the percentage air entrained within the seawater. Wave data was measured by means of a sea bed array of six pressure sensors which were logged using an underwater data logger. Data from the instrumentation mounted on the breakwater wall was logged with a high specification remote data logger. Both the instrumentation and the data acquisition equipment were developed and adapted specifically for this investigation and as a result over 150 high quality data sets were recorded at very high logging rates, which allowed field data analysis at an unprecedented level. New calibration and data processing methods were developed for the analysis of this novel set of data records. Due to the meticulous planning, instrument development, data acquisition development, and deployment the data collected is, to the best of the Author's knowledge, the highest quality wave loading field data collected to date. The wave conditions measured at the site were used as inputs to three commonly used design methods for vertical coastal structures, which were used to estimate the maximum wave loading pressures over the height of the structure. The pressures and forces predicted by the models were contrasted with measured values and it was found that the Goda method (1985) predicted the events with a high degree of accuracy provided that the waves were not breaking directly onto the structure. When waves did break onto the structure high magnitude, short duration pressures were frequently measured which sometimes also acted over a very small spatial area. There was a large degree of temporal and spatial variability in the high magnitude breaking wave pressures and they were not accurately predicted by any of the models. The relationship between wave momentum flux and wave loading impulse was investigated both on a record by record basis and using a wave by wave analysis. For the Alderney field site a consistent relationship was found between the wave momentum flux and wave loading impulse, which could be used to estimate the wave loading impulse and duration for known wave input conditions. Features of interest were also identified from temporal comparisons of individual co-located pressure and aeration traces, including negative pressures and a negative correlation between air content and pressure over short time scales.
5
Alimoglu, Murat. "Tsunami Risk Assessment Of Esenkoy Fishery Harbor Breakwater." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/4/1087832/index.pdf.
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Within the scope of this thesis, a reliability based risk assessment, based on Monte Carlo simulation was used to analyse the safety levels of Esenköy Fishery Harbor main breakwater, Sea of Marmara, Turkey. In the past, in reliability-based risk assessment methodology in Turkey, the design conditions were only wave characteristics, tidal range, storm surge, wave set-up and the structural system parameters. However in this study, the tsunami risk which was considered as a major design parameter is included in the computations. In this study, development of a structural stability criterion in coastal engineering was suggested to achieve a common definition of reliability including the tsunami risk. The model introduced in this study is a practical technique in the reliability-based risk assessment of breakwaters subject to tsunami risk. In order to determine the occurrence probability of design condition, which is a function of storm waves, tidal range, storm surge and tsunami height, the Monte Carlo simulation, was applied. From the reliability-based risk assessment model applied to Esenkö
y Fishery Harbor as a pilot study in Turkey it was found that, inclusion of the tsunami risk increases the failure risk of the structure, and as lifetime of the structure increases, the impact of tsunami risk on the failure mechanism is more reflected. For Esenkö
y Fishery Harbor main breakwater, tsunami was not the key design parameter when compared to storm waves. However, in regions with great seismic activity, tsunami risk may be very noteworthy depending on the frequency and the magnitude of the tsunami.
6
McKenna, Janice Elizabeth. "Wave forces on caissons and breakwater crown walls." Thesis, Queen's University Belfast, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263464.
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Ozeren, Yavuz. "Experimental and numerical investigations of floating breakwater performance /." Full text available from ProQuest UM Digital Dissertations, 2009. http://0-proquest.umi.com.umiss.lib.olemiss.edu/pqdweb?index=0&did=1800276571&SrchMode=1&sid=10&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1268680870&clientId=22256.
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Thesis (Ph.D.)--University of Mississippi, 2009.Typescript. Vita. "May 2009." Major professor: Alexander H.-D. Cheng Includes bibliographical references (leaves 326-335). Also available online via ProQuest to authorized users.
8
Hermanson, Michael W. "Physical modeling of a floating breakwater with a membrane." Thesis, Monterey, California. Naval Postgraduate School, 2003. http://hdl.handle.net/10945/6111.
Full textAbstract:
were tested at 8 different wave periods ranging from 0.5 seconds to 1.2 seconds and each test was performed twice. Thus, 72 combinations were examined and approximately 150 flume runs were completed to collect data for this project. The average transmission coefficient for each of the nine cases ranged from 0.705 to 0.853. In all cases tested, the addition of a membrane to the floating breakwater reduced the transmitted wave height relative to the structure with no membrane. The average wave transmission coefficient was 0.85 for the structure with no membrane. The average far all the configurations with a membrane was 0.75, or about a 12% reduction. The most effective membrane configuration gave a reduction of 17%. For the breakwater configurations and wave conditions tested, the following results were observed: (1) a membrane that is 1/4 of the water depth in length is more effective than membrane lengths of 1/2 the depth and the full depth in length, (2) lower transmission was obtained by placing the membrane at the lee side of the structure rather than the front or center, (3) a permeable membrane is more effective than an impermeable membrane, and (4) elastic mooring lines had a lower transmission than stiff moorings. (13 tables, 53 figures, 26 photographs, 16 refs.)
9
Herrera, Gamboa María Piedad. "Mound Breakwater Design in Depth-Limited Breaking Wave Conditions." Doctoral thesis, Universitat Politècnica de València, 2017. http://hdl.handle.net/10251/82553.
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The design of rubble mound breakwaters usually focuses on the main armor layer. A review of the existing literature reveals that different equations are used to design rock armors in non-breaking wave conditions. However, most rubble mound breakwaters are constructed in the depth-induced breaking zone where they are attacked by waves breaking in the foreshore; in these conditions, existing design equations are not valid. Therefore, in this PhD thesis, the hydraulic stability of double-layer rock armors is analyzed through a series of small-scale tests conducted with a bottom slope m=1/50. Based on test results, a new potential relationship is given to design rock armors in depth-limited breaking wave conditions with armor slope cot¿=1.5, stability numbers within the range 0.98¿Hm0/(¿Dn50)¿2.5, and relative water depth at the toe 3.75¿hs/(¿Dn50)¿7.50.
When concrete units are used for the armor layer, mound breakwaters are usually protected by a toe berm. This toe berm is placed on the seafloor or underlayer, providing support for the concrete armor units which are placed later on the structure slope. Toe berm design is commonly related to the armor design; in non-breaking wave conditions, the mass of toe berm rocks is one order of magnitude lower than the units of the layer. In breaking wave conditions, however, the highest waves start breaking on the bottom and impact directly on the toe berm. This is the common case of rocky sea bottoms with m=1/10 or higher slopes and thus, a correct design of the toe berm is crucial to guarantee the armor stability. The present PhD thesis examines the hydraulic stability of rock toe berms placed on a m=1/10 bottom slope and in very shallow waters (0.5El manto principal de los diques en talud suele estar formado por escollera natural o elementos prefabricados de hormigón; su función es resistir la acción del oleaje. Una revisión del estado del arte pone de manifiesto que son numerosas las fórmulas existentes para el diseño de mantos derivadas de ensayos físicos a escala reducida con oleaje sin rotura por fondo. Sin embargo, la mayoría de diques en talud se construyen en la zona de rompientes con oleaje limitado por fondo, donde las ecuaciones de diseño habituales no son del todo válidas. En esta tesis doctoral se analiza la estabilidad hidráulica de mantos bicapa de escollera, a partir de ensayos a escala reducida con pendiente de fondo m=1/50. En base a los resultados obtenidos de los ensayos físicos, se propone una nueva relación potencial para el diseño de mantos de escollera en condiciones de oleaje limitado por fondo, válida para taludes con cot¿=1.5, números de estabilidad 0.98¿Hm0/(¿Dn50)¿2.5, y profundidades relativas a pie de dique de 3.75¿hs/(¿Dn50)¿7.50. Cuando el manto principal está formado por elementos de hormigón, es habitual construir una berma de pie que proporciona apoyo a los elementos del manto y, en su caso, colabora en la protección de la zona inferior del dique contra la socavación. Dicha berma suele construirse con escollera natural y su peso está condicionado al de los elementos del manto en el caso de no haber rotura por fondo. El peso de los elementos de la berma de pie suele ser un orden de magnitud inferior al peso de las unidades del manto; sin embargo, si la pendiente de fondo es fuerte (p.e. m=1/10) y las aguas someras esta regla no se cumple ya que algunas olas rompen sobre el fondo impactando directamente sobre la berma de pie. En estos casos, el peso de la escollera de la berma puede sobrepasar el de las unidades del manto y su correcto diseño es crucial para garantizar la estabilidad del dique. Además de estudiar la estabilidad del manto principal de diques de escollera, la presente tesis doctoral analiza también la estabilidad hidráulica de bermas de pie de escollera ubicadas en fondos con pendiente m=1/10 y aguas someras (0.5
El mantell principal dels dics en talús sol estar format per roca o elements prefabricats de formigó, la seva funció és resistir l'acció de l'onatge. Una revisió de l'estat de l'art manifesta que són nombroses les equacions de disseny existents per a condicions d'onatge no trencat. No obstant això, la majoria de dics en talús es construeixen a la zona de rompents amb onatge limitat per fons, on les equacions de disseny existents no són del tot vàlides. En aquesta tesi doctoral s'analitza l'estabilitat hidràulica de mantells bicapa de roca, a partir d'assajos a escala reduïda realitzats amb pendent de fons m = 1/50. En base als resultats obtinguts dels assajos, es proposa una relació potencial per al disseny de mantells de roca en condicions d'onatge limitat per fons vàlida per a talussos amb cot¿ = 1.5, nombres d'estabilitat 0.98¿Hm0/(¿Dn50) ¿2.5, i profunditats relatives a peu de dic de 3.75¿hs/(¿Dn50)¿7.50. Quan mantell principal està format per elements de formigó , és habitual construir una berma de peu que proporciona suport als elements del mantell i, si escau, col¿labora en la protecció de la zona inferior del dic contra la soscavació. Aquesta berma sol construir amb roca i el seu pes està condicionat al dels elements del mantell en el cas de no haver trencament per fons. El pes dels elements de la berma de peu sol ser un ordre de magnitud inferior al pes de les unitats del mantell; però, si el pendent de fons és fort ( p.e. m = 1 /10) i les aigües someres aquesta regla no es compleix ja que algunes onades trenquen sobre el fons impactant directament sobre la berma de peu. En aquests casos, el pes de la roca de la berma pot sobrepassar el de les unitats del mantell, i el seu correcte disseny és crucial per garantir l'estabilitat del dic. A més d'estudiar l'estabilitat del mantell principal de dics de roca, la present tesi doctoral analitza també l'estabilitat hidràulica de bermes de roca ubicades en fons amb pendents m = 1/10 i aigües someres (0.5
Herrera Gamboa, MP. (2017). Mound Breakwater Design in Depth-Limited Breaking Wave Conditions [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/82553
TESIS
10
McLean, Niall D. "Water wave diffraction by segmented permeable breakwaters." Thesis, Loughborough University, 1999. https://dspace.lboro.ac.uk/2134/7256.
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This thesis presents an original theoretical investigation, based on diffraction theory (extended for permeable structures by Sollitt & Cross [56]), of the performance of segmented rubble mound breakwaters. The amount of protection offered by such a breakwater is a function of the rubble construction (characterized by porosity and permeability), geometry and spacing of segments as well as depending on the the characteristics of the incident wave field. To explore the influence of these factors on the performance of these breakwaters, the diffraction by three related structures have been considered :a periodic array of impermeable blocks, a single continuous rectangular section permeable structure and a periodic array of permeable blocks in shallow water.
11
Dewi, Fata Dwi Endyana Jr. "Three-Dimensional Analysis of Wave Attenuation by Anchored Hemicylindrical Shell." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/35761.
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The performance of a flexible structure as a breakwater is investigated numerically. The structure is a hemicylinder and is filled with water of uniform pressure. It is anchored along the sides. Only flexural modes are present.
The structure is modeled as an elastic shell using the finite element program ABAQUS. The fluid is assumed to be inviscid and incompressible. The fluid flow is analyzed using a boundary integral method and the integral equation is solved numerically by a panel method.
The vibration characteristics of the structure are analyzed both in the absence and presence of water. The hydrodynamic coefficients, forces, and the dynamic response of the structure in waves are obtained as a function of the wave number. Two different water depths of 5 m and 6 m are considered. For each water depth, normal and oblique incident waves are considered. The free surface elevation in front of and behind the structure is evaluated for different wave frequencies and directions. The results indicate that the flexible structure is effective in reducing the incident wave intensity over a wide range of frequencies.Master of Science
12
Knox, Paul Edward. "Examination of the performance of a longitudinal submerged breakwater system." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ63322.pdf.
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Deacon, Harriet. "A history of the Breakwater Prison from 1859 to 1905." Bachelor's thesis, University of Cape Town, 1989. http://hdl.handle.net/11427/21141.
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Bibliography: pages 85-89.This thesis is submitted in partial fulfillment of a B.A (Hons.) degree in African Studies, for which my home department was Social Anthropology. The project arose out of my interest in the interdisciplinary work of Michel Foucault and its application to the history of Africa. This has been broadened into an interest in post-structuralist theory, and has been particularly focussed on the "institution". A prime example of Foucault's "complete" or "austere" institution is the prison. The Breakwater convict station, a colonial prison in Cape Town during the nineteenth century, suited both my theoretical and empirical interests. I chose this particular institution because it was the prison from which the linguist W.H.I. Bleek drew his San informants in the 1870s, and because the prison and its records were based in Cape Town. I wanted to incorporate ideas from secondary sources on Bleek and his work (e.g. Thornton 1983, Deacon 1988a). But the work took its own directions, and I have focussed here on the organization of the prison and on the prisoners in general rather than on the San.
14
MacIntosh, Kevin J. Carleton University Dissertation Engineering Civil. "Ice interaction with a rubble mound breakwater; a case study." Ottawa, 1985.
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Li, Zhengxu. "Seabed Instability around a Submerged Breakwater due to Dynamic Loadings." Thesis, Griffith University, 2019. http://hdl.handle.net/10072/387387.
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A breakwater is one of common offshore structures for protecting ports and coastlines.
Dynamic response of a seabed around a breakwater caused by the interactions between waves
and currents is a critical aspect in evaluating the stability of the breakwater foundation. The
existence of breakwater does not only affect the propagation pattern of nearby waves but also
has a particular influence on the stability of the surrounding seabed. Under the interaction of
waves and currents, liquefaction of the seabed foundation is one of main causes of breakwater
damage, which must be fully considered in the design and construction of breakwaters. The
periodic motion of waves exerts a cyclical pressure on the interface between seawater and
seabed. Due to the effect of the cyclic wave pressures, the wave-induced residual pore
pressure will increase, and the effective stress will decrease in the seabed, which could cause
soil displacements and seabed deformation. Thus, under certain conditions, the shear failure
and liquefaction of the seabed will occur. Furthermore, under the action of cyclic wave
pressure, the normal stress and shear stress of the soil element in the seabed are cyclically
changed which will cause the principal stress axis continuously to rotate. As a consequence,
the plastic deformation of the soil is more significant, and the seabed is more prone to
liquefaction.
In this study, a one-way coupled two-dimensional numerical model is established integrating
the fluid model and the seabed model. The soil liquefaction caused by the excess
pore water pressure in the seabed is calculated by using the elasto-plastic porous medium
soil model. The feasibility of the model was verified by comparison with the laboratory
experiments, the centrifuge tests, and the previous numerical model data. It is shown that
the numerical model can simulate the dynamic response of the seabed under wave-current
interaction with high accuracy.
By adopting the integrated numerical model, the dynamic seabed response generated by
the rotation of the principal stress (PSR) axis is analysed under the cyclic wave loading. It is
found that the PSR will affect the seabed dynamic response significantly. The liquefaction
depth of the case considered PSR is much deeper than the results which did not consider the
PSR effects, since the plastic strain of the soil caused by the PSR is involved in. Secondly,
the dynamic response of seabed under different uniform current velocity and different wave conditions are solved. It is found that the following current accelerates the accumulation of
pore water pressure, increases the displacement of the soil, and makes the seabed easier to
liquefy, while the opposing current has an opposite effect. Also, the dynamic response of the
seabed under wave loading is calculated, and detailed parameter analysis of the liquefaction
potential of the seabed are carried out, including wave parameters (wave height, wave period),
and seabed parameters (soil permeability, degree of saturation).
In order to figure out the influence of the breakwater, a new-developed coupled model
is established to simulate wave-seabed-breakwater interactions under cyclic wave loading.
Firstly, the consolidation of the seabed under the effect of the self-weight of the breakwater
is calculated. The dynamic response of the seabed around the breakwater and the seabed
liquefaction depth are computed after consolidation process. Secondly, the interaction
between wave and submerged breakwater is studied by the coupled numerical model. The
influence of the height and crest width of the breakwater on the wave propagation is analysed.
The variations of wave height in front of and behind the breakwater are compared. At the
same time, the influence of breakwater height and crest width on liquefaction depth and
liquefaction potential of seabed under wave action is analysed.Thesis (Masters)
Master of Philosophy (MPhil)
School of Eng & Built Env
Science, Environment, Engineering and Technology
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Mays, Timothy Wayne Jr. "Three-Dimensional Analysis of Moored Cylinders Used as Breakwaters." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/35750.
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For oblique and normal water waves at various frequencies, the use of moored cylinders as breakwaters is considered numerically using linear three-dimensional analysis. The breakwater can be used by itself for protection of small structures or as a series of cylinders to protect a harbor, shoreline, or moored vessel from the destructive energy associated with incident water waves. The breakwater is completely submerged below the free surface and is attached to the ocean floor with six symmetrically configured mooring lines. The cylinder is filled with air and the mooring lines remain taut during the structure's motion. Six degrees of freedom describe the motion of the breakwater and additional degrees of freedom are introduced as the cables are modeled with the use of lumped masses connected with springs. The fluid is assumed to be inviscid and incompressible, so that the velocity field can be written as the gradient of the velocity potential. A boundary integral method is used to solve the integral equations that define the external fluid flow. Free vibrations of the cylinder in both air and water are considered and "dry " and "wet" natural frequencies are computed. Motions caused by water waves are studied to establish the effect of certain parameters on the effectiveness of the breakwater. The transmission coefficient is shown to be somewhat misleading when compared to plots that show the spatial variation of the wave amplitude.Master of Science
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Hettiarachchi, S. S. L. "The influence of geometry on the performance of breakwater armour units." Thesis, Imperial College London, 1987. http://hdl.handle.net/10044/1/47170.
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Lin, Fa-Lu, and 林芳如. "Studies on the overtopping reduction of berm breakwater with series submerged breakwaters." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/4444ya.
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碩士逢甲大學
土木及水利工程所
91
ABSTRACT This study is to investigate the effect of series submerged breakwaters on overtopping of berm breakwater under wave action. Experimental results shows that the berm breakwater with submerged breakwater reduce a lot of overtopping. The reducing overtopping with series submerged breakwaters is rather complicated as different intervals of series submerged breakwaters crest height location and wave condition. However, the submerged overtopping reduction factor reveals that the series submerged breakwaters better than single submerged breakwater. The overtopping equation of berm breakwater with series submerged breakwaters and that without submerged breakwater are regressed in this study. To analysis the effect of the overtopping reduction factor with the different armor unit, it results that the effect of reduction overtopping with dolos is better. The -equation by using Hebsgaard’s is gained as following： Single submerged breakwater： Series submerged breakwaters：
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Ho, Cheng-Kai, and 何程凱. "Wave Transmission Over Permeable Wubmerged Breakwater In Front of Vertical Breakwater." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/52665510864607147100.
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碩士國立中興大學
土木工程學系
87
Abstract The wave transmission over a submerged breakwater at the water surface which was placed in front of a vertical breakwater is investigated theoretically in this paper. This boundary value problem governed by the Laplace equation was solved by the separation variable method from the equations of the mixed type boundary conditions, and the conversation of mass and energy flux between adjacent region divided by the submerged breakwater .The dynamic wave pressure acted on the breakwater was analyzed in this paper. The result showed that, the wave transmission coefficient as well as the wave pressure on the breakwater, decreases to a minimum value when the value of the wave parameter Γincreases to 1 for any width and thickness of the submerged breakwater, which Γwas defined as ω2ho/g,where ω the wave frequency, ho the water depth and g the gravitational constant.
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TAO, JUN-EERN, and 陶俊仁. "BREAKWATER SOIL LIGUEFACTION ANALYSYS." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/15311631481743200303.
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Yang, Kuei Sen, and 楊貴森. "wave interaction with composite breakwater." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/53039016649065358830.
Full textAbstract:
碩士國立交通大學
土木工程學系
84
Based on a two dimensional linear water wave theory, boundary element method (BEM) and finite element method (FEM) are developed and combined tostudy the interaction of water waves with breakwater. The breakwater includestwo main types. One is mounded breakwater, the other is composite breakwater.A composite breakwater includes two parts: a mounded base and a cassion locatedon the mounded base. Computational domain is separated to area including waterand area of elastic cassion. Furthermore, the water area divided to pure waterregion and permeable region. Potential theory is applied to pure water region,and the water motion in permeable region must satisfy Darcy''s law. Areaincludind water is modeling by BEM, elastic cassion is modeling by FEM. The interaction problem will be solved by combined BEM and FEM. The aim of this report is to evaluate factors which effect the satefy ofbreakwater. There factors include wave condition, scale of cassion, andporosity and intrinsic permeability of mounded base.
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Chen, Zong-Hui, and 諶宗輝. "LIDAR Application in Breakwater Surveying." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/60938992831793114961.
Full textAbstract:
碩士國立臺灣海洋大學
河海工程學系
97
Armored blocks were used as primary wave protection of the jetty and harbor, and damaged by the northeast monsoon and typhoon very years in Taiwan. The harbor bureau were not carefully calculate the lost of armored blocks and how many blocks should to replenish to maintain its function. The impropriety maintains will case the waste or reduce the protections of the blocks. So, how to estimate the amount of the blocks is an issue for the harbor engineering. In this study, we survey the blocks of the Badouzi fishing port with LiDAR and total station with 2 different times to compare the displacement with the coordinate difference of the target and point cloud and discuss with their advantage.
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Chain, Wei-An, and 錢維安. "Wave Reflection of Chamfered Caisson Breakwater." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/19573865844685648974.
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Lu, Jenq-Shiuh, and 盧政旭. "Stability of Detached Breakwater with Berm." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/32874114733491362632.
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MO, NIAN-SHENG, and 磨年生. "Flow patterns behind the detached breakwater." Thesis, 1987. http://ndltd.ncl.edu.tw/handle/63878689450814032162.
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柯文貴. "Wave Interaction with Permeable Floating Breakwater." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/40436352930470432778.
Full textAbstract:
碩士國立中山大學
海洋環境工程研究所
85
In this thesis, analytical solutions have been developed to quantify the flow field for surge motion of a floating tension leg platform induced by a monochromatic linear wave train. The tension leg platform is anchored to the sea bed by pre-tensioned legs. Two types of platform are considered here, one is comprised of porous layer at low portion and capped by an impermeable layer on the top. The other type of platform, however, contains only a porous layer, and therefore a free surface exists in the porous floating body. The material properties of the porous layer are considered to be homogenous but anisotropic. Fluid inside the porous layer is assumed to be incompressible and viscous, and the flow field is initially irrational. On the other hand, the fluid outside the porous body is considered to be incompressible and inviscid, and the flow is also irrational. The nonlinear form drag in porous media is linearized according to Lorentz''s condition of equivalent work. Under the consideration of linearity, the corresponding boundary value problem is incorporated into a scattering and radiation problems. The boundary value problems are then solved by method of separation variable separately and combined to resolve all unknowns. The convergence of the series solutions is tested by increasing the number of wave modes and the existence of the solution is confirmed. The flow fields quantifying the interaction of a linear incident wave train and the floating platforms have been studied by varying the structure properties and wave conditions, such as width, draft, porosity and wave height.... In porous media, the eigenvalues are complex number. Although the real parts of eigenvalues can be located by an explicit equation, but the iteration process is sensitive to initial guess still. In tile further, the most important thing is locating the imaginary parts of roots or giving an initial guess which can adjust properly with varied linear friction drags. Besides, the drag forces on tension leg will be considered or a flexible platform will be studied. Finally, the nonlinear effect on the boundary value problem is going to be discussed.
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Shu, Li Zen, and 徐立政. "Shoreline Changes behind a Single Permeable Breakwater." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/95387156682084043715.
Full textAbstract:
碩士國立成功大學
水利及海洋工程學系
84
Water waves incident on a sandy beach may generate nearshore circulations behinddetach breakwaters, which produce a varying sediment transport field resultingin shoreline changes. Previous one-line models with no flow field are limitedto describe shoreline response to detached breakwaters. A numerical modelincludes three submodels predicting wave field, nearshore currents and shorelinechanges behind a single permeable breakwater is developed in this paper. The mild-slope equation with a combination of refraction diffraction andreflection is solved in the form of hyperbolic approximation. Wave- inducednearshore currents are calculated on the basis of radiation stresses obtainedfrom wave field. Shoreline changes behind a single parallel detached breakwateris predicted from nearshore currents and continuity of sediment transport. Thevalidity of the present model is verified through experiments and reasonableagreements are found. The effects of wave steepness, distance from the shoreline to the breakwaterand porosity on shoreline changes are investigated. Numerical results showthat the ability of a breakwater to shelter water bodies from waves and formsand salient and tombolos decreased with the increase of the porosily. Thesalient grows and advances as the wave height and wave period increases.Sand spits don''t protrude in the case of S/B=1.25 , where S is the offshoredistance and B is the length of the detached breakwater, respectively.
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Manuel, Brenda. "Response of a pile restrained floating breakwater." Thesis, 1997. http://hdl.handle.net/2429/6522.
Full textAbstract:
Experimental work has been performed to assess the behaviour of a caisson-type floating breakwater restrained by adjacent vertical piles. A series of two-dimensional simulations were executed evaluating the effectiveness of the breakwater as it was subjected to various incident wave trains. The transmission coefficient was of primary interest, although the reflection coefficient, energy dissipation coefficient, and heave response amplitude operator were also evaluated from the experimental results. Two numerical models were
used to estimate the reflection coefficient from the experimental data; the two-probe
method and the least squares method. Numerical analysis was executed using the
Hydrodynamic Analysis of a Floating Breakwater software (HAFB), which is a model
based on linear wave diffraction theory to predict wave loads and motions of a floating
breakwater in oblique seas. This model was used to numerically predict the transmission
and reflection coefficients and the heave response amplitude operator. The results of the numerical model show reasonable agreement with the experimental results.
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Yi-RuChen and 陳逸儒. "Wave forces under Overtopping on Vertical Breakwater." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/rybuhz.
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YE, MIN-XIONG, and 葉敏雄. "Dynamic response of hinged breakwater to wave actions." Thesis, 1988. http://ndltd.ncl.edu.tw/handle/75796780881216960015.
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吳泓勳. "The Feasibility Study of Breakwater Using Waste Tires." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/95815550990127551089.
Full textAbstract:
碩士國立臺北科技大學
土木與防災技術研究所
89
Taiwan generated 100-110 thousand tons of waste tires every year. Because of the large volume and the non-degradable nature of the waste tires, they were not suitable to be disposed at landfill sites. Instead, they were usually stored at recycling centers, which created serious problems of public health and public safety because the tires could become media of mosquitoes bred to spread the Dengue Fever or potential fire hazards. The re-utilization of intact waste tires is not the final way of disposing waste tires. However, it does extend the life of waste tires with the lowest processing cost. This study examined the feasibility of using intact waste tires as part of river levees and shore embankments in civil engineering. Foreign research data were collected and measurements were made on the volumes and weights of intact waste tires. Experiments of structural mechanics were also performed to obtain various design parameters. The vast amount of tires potentially needed in river and ocean engineering could solve the problem of piles of waste tires. It could also extend the life cycles of these abandoned tires. This thesis focused on the material properties, construction sequence, stability analysis, and economic analysis of levees constructed with waste tires. The results proved that the use of waste tires in levees is feasible in terms of applications, safety, and cost.
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Lee, Hwang Jeng, and 黃正利. "Wave Reflection of Obliquely Incident Waves on Breakwater." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/57965665402195120893.
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Garceau, Nathalie. "Combined transmission and diffraction around a floating breakwater." Thesis, 1997. http://hdl.handle.net/2429/5950.
Full textAbstract:
Wave conditions on the sheltered side of a floating breakwater are commonly
approximated by supperposing the results of the transmitted wave field across the
breakwater, and the diffracted wave field around the ends of the breakwater, both
obtained separately. This thesis describes an experimental and numerical investigation of
the suitability of this approach. To evaluate the wave field downwave of the breakwater,
three set of laboratory tests were conducted. One relates diffraction around a fixed
breakwater extending to the seabed; another to the two-dimensional case of wave
transmission across a breakwater located at the water surface; and the third to the three-dimensional
case of combined wave transmission and diffraction past a breakwater at the
water surfaces. The experiments were carried out for a rectangular caisson with three
wave conditions and for both a fixed and freely floating breakwater.
Three numerical models of a rectangular breakwater based on linear potential theory were
used to predict results relating to transmission coefficient in the case of wave
transmission only, wave diffraction only and combined wave transmission and
diffraction. The results from the laboratory experiments and the numerical models were
compared to validate the numerical models. Also, the addition of the transmission and
diffraction solutions were compared with the combined solution, on the basis of
experimental results as well as numerical results. The numerical and experimental results have indicated that the superposition
approximation generally overestimates the combined situation, particularly for longer
waves.
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YANG, FU-BANG, and 楊輔邦. "Wave reflection and transmission of tethered tire breakwater." Thesis, 1992. http://ndltd.ncl.edu.tw/handle/42440285993399365438.
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Wu, Rui-Hsiang, and 吳瑞祥. "A study of breakwater type's wave power system." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/59113769319216362682.
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CHEN, KE-GUANG, and 陳恪光. "Numerical Investigation of Wave Field around Submerged Breakwater." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/11149477247248394474.
Full textAbstract:
碩士東南技術學院
防災科技研究所
95
The variation of wave field and the path lines of water particles around submerged obstacles are being numerically investigated in this study by using the boundary element method (BEM). This study is an further extension of the 2D numerical wave flume developed by Chou and Shih, impermeable dikes were located in an arbitrary position of the flume, by using the BEM as well as applying the Lagrange description of fluid particles movements, the variations of wave field around the breakwater are analyzed using the path line and wave field when regular wave propagate over the breakwater,. Since the results was deeply affected by the width B of the breakwater, as well as the height D and σ2h/g, the tracking of water particles motion and the appearance of eddy is investigate in this study by using different conditions of B, D and σ2h/g. The water velocities of particles increase while waves propagate above the breakwater. It shows that the direction of the eddy under the wave crest rotate contrarily with the wave direction on both sides of the breakwater. The eddy phenomenon will be conspicuous when the width B of breakwater is larger or the height D greater, the occurrence was also found obviously in Double fixed breakwater.
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Hsu, Kuo-Hsien, and 許國賢. "The Influence of Offshore breakwater on Nearshore Topography." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/90012694910501210727.
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Gu, Ming-Jou, and 古明洲. "A Study on Guiding Wave Caisson Type Breakwater." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/02776647508766726206.
Full textAbstract:
碩士國立臺灣海洋大學
河海工程學系
98
A guiding wave caisson with different backward setting of crown was investigated by dramatic model tests. With a slope set in front of the crown, the rundown water flow is expected to be redirected offshore. Instead of vertical down wash, and this reduces the force acting on the leave of the caisson which always causes the loss of caisson unit, and exposes the rubble mound formation to severe wave conditions. Three different set up of the caisson were investigated in regular wave tests with seven wave periods in three repeats each. Wave pressure on the front wall, beneath the caisson and on the rubble mound formation, the wave profile in front of the caisson, and also the overtopping discharges were measured. The results show that, due to the current backward distance is not enough, the guiding slope might enlarge the runup of incident waves, and caisson the large wave force and overtopping discharges. No dominant effect on redirect the down wash water flow.
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Huei, Wang Jyr, and 王植煇. "Experimental Study on Sand Trapped behind The Submerged Breakwater." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/80908164305952134017.
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Li, Cyong-Yu, and 李瓊瑜. "DEFORMATION OF SOLITARY WAVES PASSING OVER A SUBMERGED BREAKWATER." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/96e3m2.
Full textAbstract:
碩士中原大學
土木工程研究所
101
In this research, a numerical scheme that employs a potential-vorticity decomposition is used to simulate the two-dimensional flow of a solitary wave passing over a submerged breakwater. Free surface deformation and the induced irrotational flow field are solved using a boundary integral method, and the vertical flow field induced by vorticity is solved via a vortex method. The major advantage of this method is the efficiency of the boundary integral method for solving the free surface motion and irrotational flow field, and the essentially grid-free nature of the vortex method for the vorticity field, which is predominantly confined in compact regions. In order to understand the deformation of solitary waves passing over a submerged breakwater, a series of simulations were performed with various wave heights to study the effect of vortex generation on the deformation of solitary waves. According to the numerical results, the wave forms under the assumption of irrotational and rotational flow have considerable differences. The reason is that the generated vortex may uplift the free surface. The numerical results also show that the strength of vortex and the disturbance of free surface caused by vorticity become stronger when the incident wave is higher. If the shedding vortex moves close to the freesurface, severe disturbance will be produced and leads to wave breaking.
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Chen, Jeng Huei, and 陳政輝. "Wave Transmission and Stability at Detached Breakwater with Berm." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/77346334928647678572.
Full textAbstract:
碩士逢甲大學
土木及水利工程研究所
87
The effecting factors to the transmission coefficient are wave height,period,water depth, berm width,slope and grain size etc.Transmission wave of overtopping and permeable component.If shallow water depth,more period,narrow berm width and steeper slope transmission coefficient are more. On the stability of seadike hand,paraneters such as damage index,stability number. It reveals that the shallower water depth,narrower berm,steeper slope,small grain size would cause more serious damage of dike.
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Li, Jyun-yan, and 李俊延. "Interaction of Water Waves and a Semi-Infinite Breakwater." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/90220953560022207907.
Full textAbstract:
碩士國立成功大學
水利及海洋工程學系碩博士班
96
In this study, the unsteady 3D Navier-Stokes equations and the fully nonlinear free surface boundary conditions were solved numerically to simulate both the wave and flow fields induced by waves propagating through a semi-infinite breakwater. The finite-analytic method was used to discretize the partial different equation, and the mark-and-cell (MAC) method was extended to treat the 3D free surfaces. A piston-type wave generator was incorporated in the computational domain to generate the incident waves. As the 3D numerical computation requires a huge memory and a long computational time, the computational was carried out on a PC-cluster established by connecting ten personal computers. The accuracy of the numerical model was verified by checking the relative volume error in the computational domain with respect to the size of grid cell and time step. The numerical wave fields induced by linear waves propagating through a semi-infinite breakwater were shown to be in good agreement with the theoretical solutions. Before investigating the interaction of waves and a semi-infinite breakwater, the 3D wave tank simulated the propagation of water waves over a submerged 2D breakwater and the diffraction of a solitary wave by a semi-infinite breakwater. Comparing numerical results with the experimental data proves that this wave tank can correctly simulate the interaction of waves and offshore structures. Our numerical results show that as a solitary wave propagates over a semi-infinite breakwater, vortices and vertical velocity components are induced at the region near the head of the breakwater. These may be the primary reasons for causing the scouring near the breakwater head.
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Hong, Chin-Wen, and 洪金雯. "Numerical Simulation of Wave Height Changes behind Submerged Breakwater." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/90591575115860882266.
Full textAbstract:
碩士國立中興大學
土木工程學系所
94
ABSTRACT The situations of the wave height changed and wave breaking behind a detached submerged breakwater, is the key to predict shoreline. In this study, a numerical simulation model was established to calculated the wave field. In the numerical simulations, various combinations of wave conditions and the breakwater submerged geometric conditions were calculated to explore the wave height behind detached submerged breakwater. The comparison with the case of Watanabe in 1986 has good agreement. The numerical results indicated that the wave energy decays less and the diffraction is not obvious with the submerged depth increasing. It was also shown that broaden breakwater width the wave height decayed much. The wave incident angle also affects wave height, breaking line and the peak of gradient of breaking height shifts. This paper is also depended on the gradient of breaking height to count the property of alongshore sediment transport. It shows that the submerged depth is deeper the alongshore sediment is less and to form salient or tombolo is harder.
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Chen, Chia-Hsing, and 陳佳興. "Dynamic Behavior of Vertical Breakwater Induced by Irregular Waves." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/78020226088817493671.
Full textAbstract:
碩士國立臺灣海洋大學
河海工程學系
92
In this study, a series of hydraulic model test about the dynamic behavior of vertical breakwater induced by irregular waves had been carried out in a large wave flum. In order to investigate the suitability of wave train used in irregular wave tests, four wave conditions introducing into JONSWAP spectrum with different random wave phase sets are employed. From the measurements and analyses of wave motions in front of the breakwater, wave pressure acting on vertical wall and the bottom, displacements, pitching angles and accelerations of the caisson, the dynamic behavior of caisson was discussed. Due to too many resources invole in the caisson’s acceleration and pitching motions to analyze, the relations between wave motion and wave forces, and the displacement of the caisson were discussed in the paper. The results show that the irregular wave tests should employ irregular wave train with different component wave phases, instead of repeating with only one wave train, to satisfy the charactersistics of irregular waves. Goda’s wave force theory cannot cover the pressure distribution on vertical wall and bottom in our cases. Also, the results of model test with regular waves cannot cover the case with irregular waves. More works should be done to find the suitable represntatve waves in regular wave tests. Finally, the consolidation of sea bottom will seriously affect the dynamic behavior of caisson and the accuracy of the experiment.
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Lin, Ying-Chieh, and 林英傑. "Dynamic Behavior of Vertical Breakwater Induced by Regular Waves." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/79720576834818263286.
Full textAbstract:
碩士國立臺灣海洋大學
河海工程學系
92
In this study, a series of hydraulic model tests about the dynamic behavior of breakwater induced by regular waves had been carried out in a large wave flume. Ten wave cases including four wave periods with eight repeats were tested. The wave motions in front of the breakwater, wave pressure acting on vertical wall and the bottom, displacements, pitching angles, and accelerations of the caisson were measured simultaneously. Due to too many resources involve in the caisson’s acceleration and pitching to analyze, the relations between wave motion and wave forces, and the displacement of the caisson were discussed in the paper. Compare to Goda’s force theory, the pressure distributions on vertical wall and bottom are different, and the vertical pressure at sea of the bottom is smaller than the horizontal pressure at toe, and non-zero at the port side, the total horizontal forces are varied. The range of pitching motion and the permanent displacement of the caisson are increased when wave height and period increased. From the simulation of typhoon wave acting duration, we found a threshold wave force to distinguish the linear stable relation between wave force and caisson motion, and the unstable relation between them.
46
施俞輔. "Experiment Study of Wave Breaking on Rectangular Submerged Breakwater." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/57222187618838500867.
Full textAbstract:
碩士國立海洋大學
河海工程學系
91
This study is on regular wave passing submerged breakwater in the flume. Including energy transfer , wave deformation , reflected coefficient ,transmission coefficient and water elevation change above submerged breakwater . Energy losses had gotten by energy convention law . Energy distribution in the flume was calculated by spectra analysis to confer energy distribution and transfer . The result shows when kh=0.96-2.88 B/Lo=0.153-0.917 and wave breaking above breakwater . The reflected coefficient decreases with increasung submerged breakwater relative submerged . The transmission coefficient decreases with increasing initial steepness , increasing submerged breakwater width and decreasing submerged depth of submerged breakwater . The losses of energy increases with increasing initial steepness increasing , decreasing submerged depth and increasing breakwater width . We synthesize wave breaking and nonbreaking condition with spectra analysis . Nonlinear wave deformation will cause energy transfer to high frequency zone . High frequency energy disperse gradually after wave passes through submerged breakwater . It is the reason of energy loss in wave no breaking condition . Rectangular submerged breakwater experiment on horizontal bottom , in this mode test condition , least breaker initial steepness is Ho/Lo=1.15(Ho/Lo)2+0.41(Ho/Lo)-0.002 . About breaking criteria , in the model test condition , breaker height is increase with increasing submerged depth . Regression tendency line approach a direct rat
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Huang, Chi-Da, and 黃棨達. "Influence of the Submerged Breakwater to the Wave Runup." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/86970747768370410045.
Full textAbstract:
碩士逢甲大學
土木及水利工程研究所
89
In this study, the wave runup theorem that proposed by Cross and Sollitt(1972) was quote to use first. The idea that the concept of the decay wave which propagate and pass over the submerged breakwater was applied to use at the second. After that, a relative wave runup height prediction model was presented. The comparison between the predicted wave runup and the measured runup wave was coincide each other quite well. Next, in this study, in front of the sea dyke, there have the submerged breakwater was installed for reduce the incident wave. The shape as well as the location of the submerged breakwater was changed at different condition of the incident wave to see the change of the runup waves. From the result of the experiment we find the tendency of the wave runup by this experiment was quite similar to that obtained by van der Meer(1992) for smooth surface of the sea dyke. Meanwhile, when the dyke surface was changed from smooth to step style, the phenomenon of the wave runup on the sea dyke was keep its characteristics still. That means the tendency of the wave runup was similar to those obtained by van der Meer’s. In addition, from the experiment, we find the depth of submerged breakwater that submerged can influence the wave runup on the sea dyke very much. The length of the crest of the submerged breakwater can influence the wave runup height was not so much. As to the affection of the location of the submerged breakwater to the wave runup, the result of the experiment was shows that it was not so big also.
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Ruey-Chang, Hsu, and 許瑞昌. "Wave Interaction with a Series of Submerged Porous Breakwater." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/61537356275104111616.
Full textAbstract:
碩士國立交通大學
土木工程系
87
Base on a two dimensional linear water wave theory ,this work develops the boundary element method (BEM) with linear element to examine the interaction of oblique water waves with a series of submerged permeable breakwaters. In this study , the flow field is separated into two regions: a pure water region and a porous structure regionPotential throry is applied to the pure water region,and the pore velocity potential theory of Sollitt and Cross is applied to the porous structure region.Numerical results for reflection,transmission and energy dissipation will be provided.The reflection and transmission coefficients of water wave are effected by the incident angle of wave,the height of breakwater , the shape of breakwater,the width of breakwater and the clearance between each breakwaters.The numerical technique's accuracy is confirmed by comparing the numerical results with previously numerical and experimental ones of the interaction of waves with single submerged permeable breakwater.
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YU, CHUNG-HWA, and 余倉華. "Irregular wave transmission characteristics of the tire breakwater surface." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/60018382292501928197.
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Lin, Jian-Chih, and 林建志. "Experiments of perforated breakwater with a wave-absorbing chamber." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/62110251445528948917.
Full textAbstract:
碩士國立中興大學
土木工程學系所
98
In this thesis, a series of experiments were conducted for the investigations of the wave characteristics in front of a caisson breakwater with wave-absorbing chamber. The perforated wall of the wave chamber consists of sloping-slit in the upper part and vertical-slit in the lower part. In the experiments, both the time history of wave profiles and the wave pressures at the wall of caisson were measured, and compared with the numerical simulations using CFD code, Flow-3D. The experimental results show in very good agreement with the numerical results. The wave reflection from the breakwater and the wave pressure distribution on the wall were analyzed. Due to energy dissipation induced by the wave chamber, it was found that not only the wave reflection was reduced but the wave pressure was also reduced. The results showed that the wave reflection decreased with the relative width of the wave chamber to a minimum value then increased, for a fixed porosity of the perforated wall. For a fixed relative width of the wave chamber, the wave reflection decreased with the incident wave steepness. But the maximum wave pressure on the wall at the mean water level increased with the incident wave steepness.