Showing papers on "Breaking wave published in 2017"
TL;DR: In this article, the problem formulations of models for three-dimensional weakly nonlinear shallow water waves regime in a stratified shear flow with a free surface were studied and the traveling wave solutions were generated.
Abstract: The problem formulations of models for three-dimensional weakly nonlinear shallow water waves regime in a stratified shear flow with a free surface are studied. Traveling wave solutions are generat...
123 citations
TL;DR: In this article, the first and higher harmonic components of the resonant fluid response in the gap between two identical fixed rectangular boxes are experimentally investigated in a wave basin and it is shown that for an incident group with appropriate frequency content, the linear gap response may be substantially smaller than the second-harmonic component, which is strongly driven via quadratic coupling of the linear terms from the incident wave and occurs in gap resonant modes.
Abstract: The first- and higher-harmonic components of the resonant fluid response in the gap between two identical fixed rectangular boxes are experimentally investigated in a wave basin. Gap response is excited by transient wave groups (being based on scaled versions of the autocorrelation function of sea state spectra, representing NewWaves, the average shape of large waves in a sea state). Several different wave groups with different maximum surface elevations, spectral peak frequencies and bandwidths are used, while the bilge shape of the boxes and approach angle of the waves are also varied. Unlike a simple regular wave, it is complicated to separate the harmonic components for a transient wave group due to non-linear wave-wave and wave-structure interactions. A four-phase combination methodology is used to separate the first four harmonic components, and this also allows higher-harmonic components to be isolated with simple digital frequency filtering. Harmonic components up to 14th order in the incident wave amplitude have been extracted. It is shown that for an incident group with appropriate frequency content, the linear gap response may be substantially smaller than the second-harmonic component, which is strongly driven via quadratic coupling of the linear terms from the incident wave and occurs in the gap resonant modes. Double frequency excitation may have important practical implications for offshore operations. Fourth and zeroth (long wave) harmonics in the gap are further driven via quadratic coupling of the second-harmonic itself. Linear damping coefficients for the first few modes of the gap resonant response are derived from measured time series using a numerical fit and shown to be higher than those from linear diffraction calculations.
101 citations
TL;DR: In this paper, the performance of two wave models under hurricane conditions was investigated and compared using the well-observed hurricane case Ivan (2004) as an example, and it was shown that enhancing the strength of negative wind input properly can effectively improve model skills in such situations.
98 citations
TL;DR: In this paper, the authors investigated the temporal evolution of the size distribution of subsurface oil droplets generated as breaking waves entrain oil slicks, and they used particle image velocimetry (PIV) to measure droplet sizes.
Abstract: This laboratory experimental study investigates the temporal evolution of the size distribution of subsurface oil droplets generated as breaking waves entrain oil slicks. The measurements are performed for varying wave energy, as well as large variations in oil viscosity and oil-water interfacial tension, the latter achieved by premixing the oil with dispersant. In situ measurements using digital inline holography at two magnifications are applied for measuring the droplet sizes and Particle Image Velocimetry (PIV) for determining the temporal evolution of turbulence after wave breaking. All early (2–10 s) size distributions have two distinct size ranges with different slopes. For low dispersant to oil ratios (DOR), the transition between them could be predicted based on a turbulent Weber (We) number in the 2–4 range, suggesting that turbulence plays an important role. For smaller droplets, all the number size distributions have power of about −2.1, and for larger droplets, the power decreases well below −3. The measured steepening of the size distribution over time is predicted by a simple model involving buoyant rise and turbulence dispersion. Conversely, for DOR 1:100 and 1:25 oils, the diameter of slope transition decreases from ∼1 mm to 46 and 14 µm, respectively, much faster than the We-based prediction, and the size distribution steepens with increasing DOR. Furthermore, the concentration of micron-sized droplets of DOR 1:25 oil increases for the first 10 min after entrainment. These phenomena are presumably caused by the observed formation and breakup oil microthreads associated with tip streaming.
84 citations
TL;DR: In this paper, the authors review progress made in the past decade toward understanding the different processes that can lead to turbulence during the generation, propagation, and reflection of internal waves and how these processes affect mixing.
Abstract: Internal gravity waves are a key process linking the large-scale mechanical forcing of the oceans to small-scale turbulence and mixing. In this review, we focus on internal waves generated by barotropic tidal flow over topography. We review progress made in the past decade toward understanding the different processes that can lead to turbulence during the generation, propagation, and reflection of internal waves and how these processes affect mixing. We consider different modeling strategies and new tools that have been developed. Simulation results, the wealth of observational material collected during large-scale experiments, and new laboratory data reveal how the cascade of energy from tidal flow to turbulence occurs through a host of nonlinear processes, including intensified boundary flows, wave breaking, wave-wave interactions, and the instability of high-mode internal wave beams. The roles of various nondimensional parameters involving the ocean state, roughness geometry, and tidal forcing are desc...
82 citations
TL;DR: In this article, an empirical parameterization of wave front slope angle used in the characterization of shoaling and breaking waves in nearshore environment is presented, which is applicable to both the first and second breakpoints for regular wave breaking over sloping and barred beaches.
79 citations
TL;DR: In this article, the authors prove wave breaking in the nonlinear nonlocal equation which combines the dispersion relation of water waves and a nonlinearity of the shallow water equations, provided that the slope of the initial datum is sufficiently negative.
68 citations
TL;DR: In this paper, the authors present airborne observations from two experiments: 1) the High-Resolution Air-Sea Interaction (HiRes) experiment, with measurements across an upwelling jet off the coast of Northern California, and 2) an experiment in the Gulf of Mexico with measurements of waves interacting with the Loop Current and associated eddies.
Abstract: Wave–current interaction can result in significant inhomogeneities of the ocean surface wave field, including modulation of the spectrum, wave breaking rates, and wave statistics. This study presents novel airborne observations from two experiments: 1) the High-Resolution Air–Sea Interaction (HiRes) experiment, with measurements across an upwelling jet off the coast of Northern California, and 2) an experiment in the Gulf of Mexico with measurements of waves interacting with the Loop Current and associated eddies. The significant wave height and slope varies by up to 30% because of these interactions at both sites, whereas whitecap coverage varies by more than an order of magnitude. Whitecap coverage is well correlated with spectral moments, negatively correlated with the directional spreading, and positively correlated with the saturation. Surface wave statistics measured in the Gulf of Mexico, including wave crest heights and lengths of crests per unit surface area, show good agreement with seco...
68 citations
TL;DR: Simulations with the new algorithm show that entrainment rates increase more rapidly with wind speed than previously predicted based on the existing Delvigne and Sweeney's (1988) model, and a quasi-stable droplet size distribution is developed in the near surface water.
60 citations
TL;DR: In this paper, the dependence of the whitecap coverage on wind speed, wave age, wave steepness, mean square slope, and wind-wave and breaking Reynolds numbers was determined from over 600 highfrequency visible imagery recordings of 20 min each.
Abstract: Concurrent wavefield and turbulent flux measurements acquired during the Southern Ocean (SO) Gas Exchange (GasEx) and the High Wind Speed Gas Exchange Study (HiWinGS) projects permit evaluation of the dependence of the whitecap coverage W on wind speed, wave age, wave steepness, mean square slope, and wind-wave and breaking Reynolds numbers. The W was determined from over 600 high-frequency visible imagery recordings of 20 min each. Wave statistics were computed from in situ and remotely sensed data as well as from a WAVEWATCH III hindcast. The first shipborne estimates of W under sustained 10-m neutral wind speeds U10N of 25 m s−1 were obtained during HiWinGS. These measurements suggest that W levels off at high wind speed, not exceeding 10% when averaged over 20 min. Combining wind speed and wave height in the form of the wind-wave Reynolds number resulted in closely agreeing models for both datasets, individually and combined. These are also in good agreement with two previous studies. When exp...
56 citations
01 Feb 2017
TL;DR: In this paper, the effects of the breaking characteristics, the geometric properties, the relative cylinder positions and the incident wave heights on the breaking wave force characteristics were examined with the three-dimensional CFD model REEF3D.
Abstract: In the present study, breaking solitary waves over a sloping seabed and breaking wave forces on a vertically mounted cylinder are simulated with the three-dimensional CFD model REEF3D. The numerical model uses the Reynolds-Averaged Navier–Stokes (RANS) equations together with the level set method (LSM) for the free surface and the $$k-\omega $$
for the turbulence. The numerical model is validated for simulating breaking solitary waves and breaking wave forces against the experimentally measured free surface profiles and vertical and horizontal velocities by Mo et al. (Ocean Eng 74:48–60, 2013) and the experimentally measured free surface elevation and breaking wave force by Chakrabarti et al. (Appl Ocean Res 19:113–140, 1997). The main purpose of the paper is to examine the effects of the breaking characteristics, the geometric properties, the relative cylinder positions and the incident wave heights on the breaking wave force characteristics. A total of 21 simulations are performed to investigate the characteristics and the geometric properties of solitary waves breaking over a slope and the associated breaking wave forces on a cylinder. First, the characteristics and geometric properties of breaking solitary waves are investigated with two-dimensional simulations. Further, the study explores the effect of the relative distance between the breaking point and the cylinder on breaking wave forces. Finally, the study examines breaking solitary wave forces for different incident waves. This also includes the analysis of breaking wave force characteristics such as the impact duration and rise time, the peak force, the average slamming coefficient and the force impulse. The results of the numerical simulations show that the relative distance between the cylinder and the breaking point plays an important role in obtaining the maximum force. In addition, the numerical model is capable of representing the most important physical flow features related to the breaking solitary waves and the interaction with the vertical slender cylinder.
TL;DR: In this article, the HiWinGS project successfully measured gas transfer coefficients (k660) with coincident wave statistics under conditions with hourly mean wind speeds up to 24 m s−1 and significant wave heights to 8 m.
Abstract: A variety of physical mechanisms are jointly responsible for facilitating air-sea gas transfer through turbulent processes at the atmosphere-ocean interface. The nature and relative importance of these mechanisms evolves with increasing wind speed. Theoretical and modeling approaches are advancing, but the limited quantity of observational data at high wind speeds hinders the assessment of these efforts. The HiWinGS project successfully measured gas transfer coefficients (k660) with coincident wave statistics under conditions with hourly mean wind speeds up to 24 m s−1 and significant wave heights to 8 m. Measurements of k660 for carbon dioxide (CO2) and dimethylsulfide (DMS) show an increasing trend with respect to 10-meter neutral wind speed (U10N), following a power-law relationship of the form: math formula and math formula. Among seven high wind speed events, CO2 transfer responded to the intensity of wave breaking, which depended on both wind speed and sea state in a complex manner, with k660 co2 increasing as the wind sea approaches full development. A similar response is not observed for DMS. These results confirm the importance of breaking waves and bubble injection mechanisms in facilitating CO2 transfer. A modified version of the Coupled Ocean-Atmosphere Response Experiment Gas transfer algorithm (COAREG ver. 3.5), incorporating a sea state-dependent calculation of bubble-mediated transfer, successfully reproduces the mean trend in observed k660 with wind speed for both gases. Significant suppression of gas transfer by large waves was not observed during HiWinGS, in contrast to results from two prior field programs.
TL;DR: In this paper, a large-eddy simulation (LES) study of wave breaking processes over a near-prototype scale barred beach was performed using the open-source CFD toolbox OpenFOAM.
Abstract: To understand the interaction between wave-breaking induced turbulent coherent structures and suspended sediment transport, we report a Large-Eddy Simulation (LES) study of wave breaking processes over a near-prototype scale barred beach. The numerical model is implemented using the open-source CFD toolbox, OpenFOAM®, in which the incompressible three-dimensional filtered Navier-Stokes equations for the water and air phases are solved with a finite volume scheme. A Volume of Fluid (VOF) method is used to capture the evolution of the water-air interface. The numerical model is validated with measured free surface elevation, turbulence averaged flow velocity, turbulent intensity, and for the first time, the intermittency of breaking wave turbulence. Simulation results confirm that as the obliquely descending eddies (ODEs) approach the bottom, significant bottom shear stress is generated. Remarkably, the collapse of ODEs onto the bed can also cause drastic spatial and temporal changes of dynamic pressure on the bottom. By allowing sediment to be suspended from the bar crest, intermittently high sediment suspension events and their correlation with high turbulence and/or high bottom shear stress events are investigated. The simulated intermittency of sediment suspension is similar to previous field and large wave flume observations. Coherent suspension events account for only 10% of the record but account for about 50% of the sediment load. Model results suggest that about 60∼70% of coherent bottom stress events are associated with surface-generated turbulence. Nearly all the coherent sand suspension events are associated with coherent turbulence events due to wave-breaking turbulence approaching the bed. This article is protected by copyright. All rights reserved.
TL;DR: In this paper, a field experiment designed to capture the time-varying free-surface throughout the surf and swash zones was conducted on a dissipative sandy beach using an array of 2D LiDAR scanners.
TL;DR: In this article, the effects of the incident wave amplitude and its type on the relative wave energy distribution inside the harbor are investigated. And the maximum runup and rundown of various incident waves are also discussed.
TL;DR: In this paper, the authors analyzed a large-amplitude mountain wave event, which was observed by a ground-based lidar above New Zealand between 31 July and 1 August 2014 and found that the propagation of mountain waves into the middle atmosphere is influenced by two different processes at different stages of the event.
Abstract: We analyze a large-amplitude mountain wave event, which was observed by a ground-based lidar above New Zealand between 31 July and 1 August 2014. Besides the lidar observations, European Centre for Medium-Range Weather Forecasts (ECMWF) data, satellite observations, and ray tracing simulations are utilized in this study. It is found that the propagation of mountain waves into the middle atmosphere is influenced by two different processes at different stages of the event. At the beginning of the event, instabilities in a weak wind layer cause wave breaking in the lower stratosphere. During the course of the event the mountain waves propagate to higher altitudes and are refracted southward toward the polar night jet due to the strong meridional shear of the zonal wind. As the waves propagate out of the observational volume, the ground-based lidar observes no mountain waves in the mesosphere. Ray tracing simulations indicate that the mountain waves propagated to mesospheric altitudes south of New Zealand where the polar night jet advected the waves eastward. These results underline the importance of considering horizontal propagation of gravity waves, e.g., when analyzing locally confined observations of gravity waves.
Book•
27 Oct 2017
TL;DR: The most appropriate general-purpose computer program to include wave-current interaction is the Dutch Rijkswaterstaat program CREDIZ, which is based on a parabolic wave equation.
Abstract: : This report presents an overview of wave-current interacion, including comprehensive review of references to significant U.S. and foreign literature available through December 1981. Specific topics under review are the effects of horizontally and vertically varying currents on waves, wave refraction by currents, dissipation and turbulence, small- and medium-scale currents, caustics and focusing, and wave breaking. The results of the review are then examined for engineering applications. The most appropriate general-purpose computer program to include wave-current interaction is the Dutch Rijkswaterstaat program CREDIZ, which is based on a parabolic wave equation. Further applications include wave and current forces on structures and possibly sediment transport. The report concludes with a brief state-of-the-art review of wave-current interaction and a list of topics needing further research and development.
TL;DR: In this paper, the authors used the SWASH model to reproduce wave setup and runup in highly dissipative stormy conditions using data collected during the ECORS Truc Vert’08 Experiment, especially during the Johanna storm in the winter of 2007-008 (wave setup under Hs= 8.2 m and Tp= 18.3 m and run up under 6.4 m).
TL;DR: In this article, the authors explore empirical parameterizations that incorporate both wind speed and sea state dependence via wave-wind and breaking Reynolds numbers, RH and RB, and show that wave-related Reynolds numbers collapse four open ocean data sets that have a wind speed dependence of CO₂ transfer velocity ranging from lower than quadratic to cubic.
Abstract: Predicting future climate hinges on our understanding of and ability to quantify air‐sea gas transfer. The latter relies on parameterizations of the gas transfer velocity k, which represents physical mass transfer mechanisms and is usually parameterized as a nonlinear function of wind forcing. In an attempt to reduce uncertainties in k, this study explores empirical parameterizations that incorporate both wind speed and sea state dependence via wave‐wind and breaking Reynolds numbers, RH and RB. Analysis of concurrent eddy covariance gas transfer and measured wavefield statistics supplemented by wave model hindcasts shows for the first time that wave‐related Reynolds numbers collapse four open ocean data sets that have a wind speed dependence of CO₂ transfer velocity ranging from lower than quadratic to cubic. Wave‐related Reynolds number and wind speed show comparable performance for parametrizing dimethyl sulfide (DMS) which, because of its higher solubility, is less affected by bubble‐mediated exchange associated with wave breaking.
TL;DR: In this article, the authors present direct numerical simulations of the two-phase air-water Navier-Stokes equations describing focusing wave packets, investigating the Lagrangian drift by tracking tracer particles in the water before, during and after the breaking event.
Abstract: The Lagrangian transport due to non-breaking and breaking focusing wave packets is examined. We present direct numerical simulations of the two-phase air–water Navier–Stokes equations describing focusing wave packets, investigating the Lagrangian drift by tracking tracer particles in the water before, during and after the breaking event. The net horizontal transport for non-breaking focusing packets is well described by the classical Stokes drift, both at the surface and in the bulk of the fluid, where the e-folding scale of the evanescent vertical profile is given by the characteristic wavenumber. For focusing wave packets that lead to breaking, we observe an added drift that can be ten times larger than the classical Stokes drift for a non-breaking packet at the surface, while the initial depth of the broken fluid scales with the wave height at breaking. We find that the breaking induced Lagrangian transport scales with the breaking strength. A simple scaling argument is proposed to describe this added drift and is found to be consistent with the direct numerical simulations. Applications to upper ocean processes are discussed.
TL;DR: In this paper, the authors present both linear and nonlinear analyses of extreme responses for a multi-body wave energy converter (WEC) in severe sea states, showing that the overall response is remarkably linear until temporary submergence of the central float.
Abstract: This paper presents both linear and nonlinear analyses of extreme responses for a multi-body wave energy converter (WEC) in severe sea states. The WEC known as M4 consists of three cylindrical floats with diameters and draft which increase from bow to stern with the larger mid and stern floats having rounded bases so that the overall system has negligible drag effects. The bow and mid float are rigidly connected by a beam and the stern float is connected by a beam to a hinge above the mid float where the rotational relative motion would be damped to absorb power in operational conditions. A range of focussed wave groups representing extreme waves were tested on a scale model without hinge damping, also representing a more general system of interconnected cylindrical floats with multi-mode forcing. Importantly, the analysis reveals a predominantly linear response structure in hinge angle and weakly nonlinear response for the beam bending moment, while effects due to drift forces, expected to be predominantly second order, are not accounted for. There are also complex and violent free-surface effects on the model during the excitation period driven by the main wave group, which generally reduce the overall motion response. Once the main group has moved away, the decaying response in the free-vibration phase decays at a rate very close to that predicted by simple linear radiation damping. Two types of nonlinear harmonic motion are demonstrated. During the free-vibration phase, there are only double and triple frequency Stokes harmonics of the linear motion, captured using a frequency doubling and tripling model. In contrast, during the excitation phase, these harmonics show much more complex behaviour associated with nonlinear fluid loading. Although bound harmonics are visible in the system response, the overall response is remarkably linear until temporary submergence of the central float (‘dunking’) occurs. This provides a strong stabilising effect for angular amplitudes greater than and can be treated as a temporary loss of part of the driving wave as long as submergence continues. With an experimentally and numerically derived response amplitude operator (RAO), we perform a statistical analysis of extreme response for the hinge angle based on wave data at Orkney, well known for its severe wave climate, using the NORA10 wave hindcast. For storms with spectral peak wave periods longer than the RAO peak period, the response is controlled by the steepness of the sea state rather than the wave height. Thus, the system responds very similarly under the most extreme sea states, providing an upper bound for the most probable maximum response, which is reduced significantly in directionally spread waves. The methodology presented here is relevant to other single and multi-body systems including WECs. We also demonstrate a general and potentially important reciprocity result for linear body motion in random seas: the averaged wave history given an extreme system response and the average response history given an extreme wave match in time, with time reversed for one of the signals. This relationship will provide an efficient and robust way of defining a ‘designer wave’, for both experimental testing and computationally intensive computational fluid dynamics (CFD), for a wide range of wave–structure interaction problems.
TL;DR: In this article, a decomposition of the wave field into a discrete set of localized wave groups with optimal length scales and amplitudes is proposed to predict large wave formation in two-dimensional water waves.
TL;DR: In this article, the effects of wave breaking induced sea spray, ocean vertical mixing associated with non-breaking surface waves, and sea surface cooling due to intense rainfall are assessed by means of a set of numerical experiments.
Abstract: Improving intensity simulation and forecast of tropical cyclones has always been a challenge, although in recent years the track forecasts have been remarkably improved. In this study, we explore the sensitivity of typhoon simulation to three physical processes using a fully coupled atmosphere-ocean-wave model. Two storms, a strong and a weak one, have been chosen. The effects of wave breaking induced sea spray, ocean vertical mixing associated with nonbreaking surface waves, and sea surface cooling due to intense rainfall are assessed by means of a set of numerical experiments. The results show and confirm that sea spray leads to an increase of typhoon intensity by enhancing the air-sea heat flux, while nonbreaking wave-induced vertical mixing and rainfall lead to a decrease. Each process can be relevant, depending on wind and wave conditions. These can vary dramatically when typhoons interact with not sufficiently well-defined coastal areas, typically an archipelago. Compared with the control runs, when all the three physical processes are considered, the (absolute) difference between the modeled sea level pressure and best track data is reduced from 26.05 to 0.70 hPa for typhoon Haiyan, and from −9.42 to −8.67 hPa for typhoon Jebi. We have found a steady overestimate of the dimensions of the typhoons. We have verified an extreme sensitivity to the initial conditions, especially when small differences in the typhoon track may imply different relevance of the physical processes, like the ones we have considered, governing the evolution of the storm.
TL;DR: A large-scale wave flume experiment has been carried out involving a T = 4 s regular wave with H = 0.85 m wave height plunging over a fixed barred beach profile as mentioned in this paper.
Abstract: A large-scale wave flume experiment has been carried out involving a T = 4 s regular wave with H = 0.85 m wave height plunging over a fixed barred beach profile. Velocity profiles were measured at 12 locations along the breaker bar using LDA and ADV. A strong undertow is generated reaching magnitudes of 0.8 m/s on the shoreward side of the breaker bar. A circulation pattern occurs between the breaking area and the inner surf zone. Time-averaged turbulent kinetic energy (TKE) is largest in the breaking area on the shoreward side of the bar where the plunging jet penetrates the water column. At this location, and on the bar crest, TKE generated at the water surface in the breaking process reaches the bottom boundary layer. In the breaking area, TKE does not reduce to zero within a wave cycle which leads to a high level of “residual” turbulence and therefore lower temporal variation in TKE compared to previous studies of breaking waves on plane beach slopes. It is argued that this residual turbulence results from the breaker bar-trough geometry, which enables larger length scales and time scales of breaking-generated vortices and which enhances turbulence production within the water column compared to plane beaches. Transport of TKE is dominated by the undertow-related flux, whereas the wave-related and turbulent fluxes are approximately an order of magnitude smaller. Turbulence production and dissipation are largest in the breaker zone and of similar magnitude, but in the shoaling zone and inner surf zone production is negligible and dissipation dominates.
TL;DR: In this paper, the propagation of surface waves in both one-and two-dimensional periodic structures is investigated and an energy distribution parameter is defined and a new method for identifying surface wave modes is suggested.
TL;DR: In this article, the authors studied the fluid dynamics during the flooding of a damaged ship numerically and experimentally, focusing on the fluid flow characteristics and the fluid-structure interactions.
Abstract: The present paper studies the fluid dynamics during the flooding of a damaged ship numerically and experimentally. Attention is focused on the fluid flow characteristics and the fluid-structure interactions. The Smoothed Particle Hydrodynamics (SPH) method with an improved boundary treatment is established, which is able to capture the flow behaviors effectively. Fairly good agreement is obtained between the computational and experimental results. Based on the SPH method, the simulations are carried out for the flooding of a damaged ship with different opening sizes, opening positions, and numbers of the flooding cabins. Besides, the effects of the wave are also taken into account. The fluid behaviors are described and analyzed in detail. It is found that, during the first phase of flooding, an inflow jet with a large velocity is formed, significantly influencing the inner flows and the ship responses. During the progressive flooding phase, sloshing, crushing of the free surface, wave breaking, and vortex shedding are observed which are coupled with the ship motions. In addition, some relevant conclusions are enclosed for the motion laws of the damaged ship. This work provides physical insight into the flooding of the damaged ship, which is helpful to understand the coupled dynamics of the ship and flooding water.
TL;DR: In this article, an improved smoothed particle hydrodynamics (SPH) method is used to study wave overtopping for different coastal structures, including dam break, solitary wave breaking and wave over-topping at vertical and sloping seawalls.
TL;DR: In this article, the authors presented numerical simulation results based on a tsunami-like wave generated based on the observed tsunami wave profile measured in the Tohoku tsunami, which was numerically generated with an internal wave source method with a two-phase incompressible flow model with a volume of fluid (VOF) method to capture the free surface, and a finite volume scheme was used to solve all the governing equations.
TL;DR: The threshold for the onset of breaking proposed by Barthelemy et al. as mentioned in this paper has been investigated in the laboratory for unidirectional wave groups in deep water and extended to include different classes of wave groups and moderate wind forcing.
Abstract: The threshold for the onset of breaking proposed by Barthelemy et al. (arXiv:1508.06002v1, 2015) has been investigated in the laboratory for unidirectional wave groups in deep water and extended to include different classes of wave groups and moderate wind forcing. Thermal image velocimetry was used to compare measurements of the wave crest point (maximum elevation and also the point of maximum) surface water particle velocity ( ) with the wave crest point speed ( ) determined by an array of closely spaced wave gauges. The crest point surface energy flux ratio that distinguishes maximum recurrence from marginal breaking was found to be . Increasing wind forcing from zero to systematically increased this threshold by 2 %. Increasing the spectral bandwidth (decreasing the Benjamin–Feir index from 0.39 to 0.31) systematically reduced the threshold by 1.5 %.
TL;DR: Based on the Navier-Stokes (RANS) equations, a three-dimensional mathematical model for the hydrodynamics and structural dynamics of a floating point absorbing wave energy converter (WEC) with a stroke control system in irregular and extreme waves is presented in this paper.