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Showing papers on "Wave flume published in 2015"


Journal ArticleDOI
TL;DR: In this paper, the authors describe the validation of an SPH-based technique for wave loading on coastal structures, which is used for the scope of wave impact on vertical structures and storm return walls.

204 citations


Journal ArticleDOI
01 Apr 2015-Energy
TL;DR: Based on a time-domain HOBEM (higher-order boundary element method), a two-dimensional (2D) fully nonlinear NWF (numerical wave flume) is developed to investigate the hydrodynamic performance of a fixed OWC (oscillating water column) wave energy device as discussed by the authors.

119 citations


Journal ArticleDOI
Chunyan Ji1, Xiang Chen1, Jie Cui1, Zhiming Yuan, Atilla Incecik 
TL;DR: In this paper, a cylindrical floating breakwater (CFB) is proposed, which consists of two parts: a main body of rigid cylinders, and a flexible mesh cage containing a number of suspending balls that are intended to absorb the wave energy into their mechanical energy.

71 citations


Journal ArticleDOI
TL;DR: In this article, high-resolution observations from a 55m-long wave flume were used to investigate the dynamics of wave setup over a steeply sloping reef profile with a bathymetry representative of many fringing coral reefs.
Abstract: High-resolution observations from a 55-m-long wave flume were used to investigate the dynamics of wave setup over a steeply sloping reef profile with a bathymetry representative of many fringing coral reefs. The 16 runs incorporating a wide range of offshore wave conditions and still water levels were conducted using a 1:36 scaled fringing reef, with a 1:5 slope reef leading to a wide and shallow reef flat. Wave setdown and setup observations measured at 17 locations across the fringing reef were compared with a theoretical balance between the local cross-shore pressure and wave radiation stress gradients. This study found that when radiation stress gradients were calculated from observations of the radiation stress derived from linear wave theory, both wave setdown and setup were underpredicted for the majority of wave and water level conditions tested. These underpredictions were most pronounced for cases with larger wave heights and lower still water levels (i.e., cases with the greatest setdow...

61 citations


Journal ArticleDOI
TL;DR: In this paper, the influence of the inlet configuration on wave resonance in the gap between two side-by-side fixed bodies is investigated numerically in a 2D numerical wave flume.

55 citations


Journal ArticleDOI
TL;DR: In this paper, the authors developed a wave load model for the prediction of wave-induced forces on a slender pile in pile groups with different arrangements using a series of laboratory data obtained from systematic model tests.

53 citations


Journal ArticleDOI
TL;DR: In this paper, the impact on a column by an idealized 1:5-scale shipping container propelled by tsunami flow was modeled in a large-scale wave flume, and the results from hydraulic experiments were compared with corresponding data from in-air impact experiments using the same experimental configuration to assess the hydrodynamic effects on impact force and duration.
Abstract: Impact on a column by an idealized 1:5-scale shipping container propelled by tsunami flow was modeled in a large-scale wave flume. Results from hydraulic experiments were compared with corresponding data from in-air impact experiments using the same experimental configuration to assess the hydrodynamic effects on impact force and duration. Experiments were conducted by varying flow conditions, velocity, and nonstructural mass. An aluminum specimen was tested empty and with the addition of nonstructural mass to simulate partially loaded shipping containers. The measured peak impact forces from the longitudinal test in water were observed to have an increase no greater than 17% of the corresponding measured peak impact forces from the longitudinal test in air. The impact duration measured from the in-air test provided a lower bound for the impact duration measured for the in-water tests. Hydraulic effects were shown to increase the impact duration by an average of 20%. The additional nonstructural m...

43 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of pile group interaction on the wave loading of a pile was investigated by means of small scale experiments performed in the 2m wide wave flume of Leichtweiss-Institute for Hydraulic Engineering and Water Resources (LWI) in Braunschweig, Germany.

36 citations


Journal ArticleDOI
TL;DR: In this article, a laboratory experiment was conducted to investigate the dynamics of cross-shore sediment transport across a fringing coral reef, and the authors observed that the wave energy on the reef flat was partitioned between two primary frequency bands (high and low), and the proportion of energy within each band varied substantially across the coral reef flat, with the low-frequency waves becoming increasingly important near the shore.

36 citations


Journal ArticleDOI
TL;DR: By introducing a source term into the Laplace equation, a two-dimensional fully nonlinear time-domain numerical wave flume (NWF) was developed to investigate the resonance induced by the interaction between waves and multiple objects with narrow gaps.
Abstract: By introducing a source term into the Laplace equation, a two-dimensional fully nonlinear time-domain numerical wave flume (NWF) is developed to investigate the resonance induced by the interaction between waves and multiple objects with narrow gaps. In the numerical model, the fully nonlinear kinematic and dynamic boundary conditions are satisfied on the instantaneous free surface and the constant artificial damping is employed in the gaps to approximate the viscous dissipation due to vortex motion and flow separation. The computational domain is discretized using a higher-order boundary element method (HOBEM). The proposed model is firstly validated against the published experimental data and numerical results of the wave height in the narrow gap between two boxes, the wave heights in the two gaps of three boxes, and wave loads on the boxes. Then, the extensive numerical experiments are performed to study the influences of the number of the boxes and the gap spacing on the resonant frequency, reflected and transmitted wave heights and wave loads on the boxes.

32 citations


Journal ArticleDOI
TL;DR: In this article, a combined wave-dam-breaking (CWDB) model was proposed to reveal the formation mechanisms of rogue waves, by including the influence of the rogue wave propagation as well as the delayed effect of the dam-breaking problem.

Journal ArticleDOI
TL;DR: In this article, a methodology for accurately replicating measured ocean waves in a numerical model at full scale is detailed, where a Fourier analysis of the measured record allows the wave to be defined as a summation of linear waves and therefore, Airy's linear wave theory may be used to input the wave elevation and associated water particle velocities.

Journal ArticleDOI
TL;DR: A review of the state-of-the-art knowledge in this field, including sediment incipient motion, bed forms, bed roughness, bed load transport, suspended-load transport, equilibrium sediment concentration, and sheet flow, can be found in this article.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the impacts of a wave farm on waves, currents and coastal morphology adjacent to the wave farm, which is located in the Southwest of England (the Wave Hub).
Abstract: This study investigates impacts of a wave farm on waves, currents and coastal morphology adjacent to the wave farm, which is located in the Southwest of England (the Wave Hub) In this study, we focus on the interaction between waves and tides due to the presence of the wave farm and its effects on wave radiation stresses, bottom shear stresses and consequently on the sediment transport and the coast adjacent to the wave farm, using an integrated numerical modelling system The modelling system consists of the near-shore wave model SWAN, the ocean circulation model ROMS and a sediment transport model for morphological evolution The results show that tidal elevation and tidal currents can have a significant effect on waves and that tidal forcing and waves have a significant effect on bottom shear stresses Waves can impact on the processes related to the bottom boundary layer and mixing intensity in the water column The wave farm has an impact on the gradients of radiation shear stresses and bottom shear stresses that modify current speeds and wave heights, which in turn impact on the near-shore sediment transport and the resulting morphological changes Bed load transport rates show a decrease when the wave farm is present, even during storm conditions The results highlight the importance of the interactions between waves and tides when modelling coastal morphology with presence of wave energy devices

Journal ArticleDOI
TL;DR: In this paper, a phase-averaged measurement of sheet flow, particle velocities, and bed level evolution during a complete swash cycle is presented, showing a clear pattern of rapid erosion during the early uprush and progressive accretion during the middle backwash phase.

Journal ArticleDOI
TL;DR: In this article, a conserved wave absorption method based on the relaxation method was proposed, where instead of deciding the absorption coefficient empirically, the conserved absorption method dynamically determines the absorption coefficients by solving the mass conservation equation derived in this article.

Journal ArticleDOI
TL;DR: In this article, a case study focusing on Haydarpasa Port, located at the southern entrance of Istanbul Bosphorus Strait (North coast of the Sea of Marmara), is presented.

Journal ArticleDOI
TL;DR: In this article, image processing techniques based on edge detection algorithms were used to measure waves in the laboratory with a camera, and the experimental results showed the agreement of water surface elevation from both measurement methods.

Journal ArticleDOI
TL;DR: In this paper, a floating device called OXYFLUX is used to increase the concentration of dissolved oxygen in the underwater areas near the bottom of a wave flume. But this is based on laboratory results.

Journal ArticleDOI
TL;DR: In this article, a combined method is presented to study the wave interaction with an offshore or pile (cylinder) breakwater in finite water depth, where the influences of the fluid viscosity, the thickness of the structure and evanescent waves on the hydrodynamic behaviors are included in the model.

Journal ArticleDOI
TL;DR: In this paper, a set of 2D wave flume experiments on a sandy beach were performed to explore the sandy beach sorting and sedimentary characteristic induced by wave action, and the results showed that the sediments of sandy beach under wave action produced obvious sorting phenomenon.

Journal ArticleDOI
TL;DR: In this paper, the authors performed laboratory experiments in a wave flume to investigate sediment transport by a tsunami wave attacking sand beaches, and the experimental results showed that some of the commonly used or recent bedload formulas for steady flow or wave are not suitable for the rapid unsteady or non-uniform tsunami flow.

Journal ArticleDOI
TL;DR: In this article, a wave energy converters and vortical structure of breaking waves are analyzed at the laboratory scale through a specialized class of devices known as experimental wave flumes and numerical wave tanks (NWTs).

Journal ArticleDOI
TL;DR: In this article, the influence of relative breakwater width, relative depth of submergence of the breakwater and roughness of breakwater front slope on wave transmission is analyzed and discussed.

Journal ArticleDOI
TL;DR: In this paper, a two-dimensional fully nonlinear time-domain numerical wave flume is developed to investigate the hydrodynamics around multiple rectangular-box structures close to one another in waves.
Abstract: To analyze the hydrodynamic difference between marine structures with and without narrow gaps, a two-dimensional fully nonlinear time-domain numerical wave flume is developed to investigate the hydrodynamics around multiple rectangular-box structures close to one another in waves. In the numerical model, the incident waves are generated by inner-domain sources such that re-reflection at the input boundary can be avoided. The fully nonlinear kinematic and dynamic boundary conditions are satisfied for the instantaneous free surface, and artificial damping is used for the free surface in the gaps to model the viscous effect. The proposed model is first validated against the experimental data for an isolated box and twin- and triple-box systems with narrow gaps. Then extensive numerical experiments are performed to compare the wave heights and wave loads on rectangular boxes with and without narrow gaps. The first comparison is made between the hydrodynamics of each individual box of a multiple-box sy...

Journal ArticleDOI
TL;DR: In this paper, an experimentally validated numerical model is used to predict the current-only flow in flumes capable of combining waves and current, and the results of these simulations are then analysed to assess the performance of each flume type and to understand the fluid dynamics that govern each type.

Journal ArticleDOI
TL;DR: In this paper, the induced density-stratified fluid motion of a solitary wave propagating over a submarine trench was investigated numerically and experimentally using a measurement framework of laser-induced fluorescence and particle image velocimetry (PIV).

01 Apr 2015
TL;DR: In this article, the authors investigated the placement pattern, packing density and wave over-topping over slope of a single-layer concrete unit called crablock in a 1:4/3 slope with the use of random and uniform placement.
Abstract: In the design of rubble mound breakwaters, nowadays single layer systems using concrete armour units have become more common practice compared to conventional two layer systems. However, after the introduction of the accropode in eighties, a small number of single layer armour units have been developed over the years; for example core-loc, A-jack, xbloc, accropode-II, cubipod and core-loc II. Recently, a new concrete armour unit called crablock has been invented and applied as one layer system in one damaged breakwater at Al Fujeirah, UAE. In contrast to other existing monolayer units, the shape of this unit is symmetrical which allows placing both in uniform and random pattern. As the crablock unit is still under development, no design guidance exists yet for this concrete armour unit. To use crablock as monolayer system the preliminary design guidance on placement of crablock, stability and wave overtopping are required. This led the present research to investigate the placement pattern, packing density and wave overtopping over slope to come with first design guidance for the application of crablock. It should be mentioned that stability of the crablock against wave attack was also looked at, but that will be reported by Mr. Andre Broere, an MSc-student at Delft University of Technology. The present research was based on a literature study, small scale dry placement tests and small scale hydraulic tests in a wave flume. Regarding to the review of literature studies on the existing single layer units and crablock, set up of dry placement tests and flume tests have been made for this experimental research. Dry placement tests as well as 2D wave flume tests were carried out at the Fluid Mechanics Laboratory of the Faculty of Civil Engineering and Geosciences at Delft University of Technology, Netherlands. Both placement and hydraulic tests were executed with the use of small units. In total 14 independent placement test series were executed to investigate the placement pattern, placing grid and packing density of crablock. All the tests were performed on a 1:4/3 slope with the use of random and uniform placement in a rectangular as well as in a diamond shaped placing grid. Results of placement tests showed that uniform placement of crablock is achievable with the use of relatively small and smooth under layer in a rectangular placing grid. The performance of regular placement using a conventional under layer with size 1/10th to 1/15th of the size of the armour layer was not so satisfactory. Furthermore, it was found that uniform pattern was hardly reachable in a diamond-shaped grid with conventional under layer. However, irregular placement of crablock was certainly easier to construct and possible to place with higher accuracy compared to uniform placement in a diamond grid. It should be noted that all the tests using a conventional underlayer were performed without the fixation of first row due to the difficulties in placement with model crablock units. If this can be fixated by designing dedicated toe units (both in rotation and location) it may perform better. Still, the large underlayer makes it difficult to place uniformly. Finally, two preferred placing patterns appeared from the placement tests, a regular pattern in a rectangular grid using a relatively small under layer and a random pattern in a diamond grid using a conventional under layer. For the determination of wave overtopping, altogether 14 different test series were performed in a wave flume. In this research, two constant spectral wave steepnesses of 0.02 and 0.04 were tested together with two different orientations of units, two different placing grids and four different packing densities. The preferred placing patterns were constructed in a wave flume on a modelled breakwater cross-section in front of the sloping foreshore of 1:30. Each test series was comprised of number of sub tests for specific wave height and period. In each test series, wave heights and periods were continued to measure until the failure of armour slope. The armour layer was reconstructed prior to start of each test series. The test results of 2D flume tests showed that wave overtopping over crablock slope did not vary much between the different test series with same wave steepness. Nevertheless, it was observed that wave overtopping is little bit higher for longer wave period that means for low steepness compared to short period. Based on test results, it was also found that overtopping behaviour does not really change with the change in packing density and also with different placement pattern of armour layer. Regarding to the comparison of relative overtopping rate over crablock armour between test results and empirical prediction, it was found that that empirical equation with assuming roughness factor of 0.45 underestimate the measured wave overtopping over crablock. However, the comparison between the test results on overtopping percentages and estimation by EurOtop (2007) proved that percentage of waves overtopped over crablock can be well predicted by using empirical formula. Furthermore, the measured wave overtopping over crablock slope was found slightly higher in comparison to CLASH (2004) results on other single layer units. This variation was mainly observed for the test results with low wave steepness. Besides relatively low wave steepness, most of the tests on crablock were performed with relatively longer wave periods in comparison to CLASH (2004) which was also one of the triggering factor for higher overtopping over crablock slope compared to CLASH (2004). Moreover, the use of sloping foreshore (1:30) instead of horizontal one by CLASH (2004) might also influence the overtopping behaviour. The 1:30 slope changed the shape of the waves and the waves at the structure toe showed a clear increase in velocity of the wave crest (near or at breaking) The resulting wave overtopping over crablock slope was also compared with the overtopping over xbloc slope measured by DMC (2003). From the comparison, it was found that wave overtopping over crablock is significantly lower compared to xbloc measurements by DMC (2003). Based on the comparison of wave overtopping over different armour slope with and without Ursell parameter, it was recognised that use of the Ursell parameter may explain wave period differences in some cases, but introduces also unexpected differences.

Journal ArticleDOI
TL;DR: In this article, the coupling effects of roll motion and fluid resonance between twin rectangular barges subjected to incident waves normal to the spanwise of the narrow gap are investigated employing a two-dimensional numerical wave flume based on a CFD package OpenFOAM.

Journal ArticleDOI
TL;DR: In this article, a series of laboratory experiments were conducted to measure the run-up heights on plane slopes and wave pressures on vertical structures resulting from solitary waves, which represent the characteristics of tsunamis well.