Calculations of wave breaking probability and distribution of breaking wave heights in deep water

1997 ◽  
Vol 15 (3) ◽  
pp. 252-257
Author(s):  
Song Jin-bao ◽  
Lou Shun-li ◽  
Tian Ji-wei
Keyword(s):  
Deep Water ◽  
Wave Breaking ◽  
Breaking Wave ◽  
Wave Heights

scholarly journals PROBABILITIES OF BREAKING WAVE CHARACTERISTICS

1970 ◽  
Vol 1 (12) ◽  
pp. 25 ◽  
Author(s):  
J. Ian Collins
Keyword(s):  
Shallow Water ◽  
Probability Density ◽  
Deep Water ◽  
Surf Zone ◽  
Probability Distributions ◽  
Rayleigh Distribution ◽  
Breaking Wave ◽  
Wave Characteristics ◽  
Probability Densities ◽  
Wave Heights

Utilizing the hydrodynamic relationships for shoaling and refraction of waves approaching a shoreline over parallel bottom contours a procedure is developed to transform an arbitrary probability density of wave characteristics in deep water into the corresponding breaking characteristics in shallow Water A number of probability distributions for breaking wave characteristics are derived m terms of assumed deep water probability densities of wave heights wave lengths and angles of approach Some probability densities for wave heights at specific locations in the surf zone are computed for a Rayleigh distribution in deep water The probability computations are used to derive the expectation of energy flux and its distribution.

scholarly journals BREAKING WAVE DESIGN CRITERIA

1984 ◽  
Vol 1 (19) ◽  
pp. 2
Author(s):  
E.B. Thornton ◽  
C.S. Wu ◽  
R.T. Guza
Keyword(s):  
Wave Breaking ◽  
Laboratory Experiments ◽  
Wave Model ◽  
Rayleigh Distribution ◽  
The United States ◽  
Random Wave ◽  
Breaking Wave ◽  
Shore Protection ◽  
Design Procedures ◽  
Wave Heights

Breaking wave heights measured in both field and random wave laboratory experiments are examined. The dependence of breaker height and breaker depth on beach slope and deep water steepness is presented. The results are compared with the design curves of the Shore Protection Manual (SPM) and the predictions of the randan wave model by Goda (1975). The comparisons indicate that the significant breaker height, based on Goda's model, is slightly conservative for the experimental cases; but the maximum breaker heights are reasonably predicted by the model. The design procedures in the SPM are based on a monochromatic wave breaking, and appear overly conservative, particularly for low wave steepness (less than 0.01) which occur frequently on the West Coast of the United States. The use of the Rayleigh distribution to predict wave height statistics is tested with random wave data for both deep and shallow water regions.

scholarly journals Laboratory measurements of deep-water breaking waves

1990 ◽  
Vol 331 (1622) ◽  
pp. 735-800 ◽  
Keyword(s):  
Deep Water ◽  
Water Waves ◽  
Phase Speed ◽  
Stationary Flow ◽  
Breaking Waves ◽  
Return Flow ◽  
Breaking Wave ◽  
Wave Group ◽  
Wave Channel ◽  
Wave Heights

The results of laboratory experiments on unsteady deep-water breaking waves are reported. The experiments exploit the dispersion of deep-water waves to generate a single breaking wave group. The direct effects of breaking are then confined to a finite region in the wave channel and the influence of breaking on the evolution of the wave field can be examined by measuring fluxes into and out of the breaking region. This technique was used by us in a preliminary series of measurements. The loss of excess momentum flux and energy flux from the wave group was measured and found to range from 10% for single spilling events to as much as 25% for plunging breakers. Mixing due to breaking was studied by photographing the evolution of a dye patch as it was mixed into the water column. It was found that the maximum depth of the dye cloud grew linearly in time for one to two wave periods, and then followed a t 1/4 power law (t is the time from breaking) over a range of breaking intensities and scales. The dyed region reached depths of two to three wave heights and horizontal lengths of approximately one wavelength within five wave periods of breaking. A detailed velocity survey of the breaking region was made and ensemble averages taken of the non-stationary flow. Mean surface currents in the range 0.02-0.03 C (C is the characteristic phase speed) were generated and took as many as 60 wave periods to decay to 0.005 C. A deeper return flow due to momentum lost from the forced long wave was measured. Together these flows gave a rotational region of approximately one wavelength. Turbulent root mean square velocities of approximately 0.02 C were measured near the surface and were still significant at depths of three to four wave heights. More than 90 % of the energy lost from the waves was dissipated within four wave periods. Subsequently measured kinetic energy in the residual flow was found to have a t -1 dependence. Correlation of all the above measurements with the amplitude, bandwidth and phase of the wave group was found to be good, as was scaling of the results with the centre frequency of the group,. Local measures of the breaking wave were not found to correlate well with the dynamical measurements.

scholarly journals Characteristics of Breaking Wave Forces on Piles over a Permeable Seabed

2021 ◽  
Vol 9 (5) ◽  
pp. 520
Author(s):  
Zhenyu Liu ◽  
Zhen Guo ◽  
Yuzhe Dou ◽  
Fanyu Zeng
Keyword(s):  
Wave Breaking ◽  
Stokes Equations ◽  
Slope Angle ◽  
Wave Force ◽  
Breaking Waves ◽  
Offshore Wind ◽  
Secondary Wave ◽  
Wave Forces ◽  
Breaking Wave ◽  
Breaking Wave Forces

Most offshore wind turbines are installed in shallow water and exposed to breaking waves. Previous numerical studies focusing on breaking wave forces generally ignored the seabed permeability. In this paper, a numerical model based on Volume-Averaged Reynolds Averaged Navier–Stokes equations (VARANS) is employed to reveal the process of a solitary wave interacting with a rigid pile over a permeable slope. Through applying the Forchheimer saturated drag equation, effects of seabed permeability on fluid motions are simulated. The reliability of the present model is verified by comparisons between experimentally obtained data and the numerical results. Further, 190 cases are simulated and the effects of different parameters on breaking wave forces on the pile are studied systematically. Results indicate that over a permeable seabed, the maximum breaking wave forces can occur not only when waves break just before the pile, but also when a “secondary wave wall” slams against the pile, after wave breaking. With the initial wave height increasing, breaking wave forces will increase, but the growth can decrease as the slope angle and permeability increase. For inclined piles around the wave breaking point, the maximum breaking wave force usually occurs with an inclination angle of α = −22.5° or 0°.

scholarly journals Assessment of Numerical Methods for Plunging Breaking Wave Predictions

2021 ◽  
Vol 9 (3) ◽  
pp. 264
Author(s):  
Shanti Bhushan ◽  
Oumnia El Fajri ◽  
Graham Hubbard ◽  
Bradley Chambers ◽  
Christopher Kees
Keyword(s):  
Solitary Wave ◽  
Wave Breaking ◽  
Large Scale ◽  
Turbulence Models ◽  
Navier Stokes ◽  
Wave Crest ◽  
Breaking Wave ◽  
Rans Turbulence Models ◽  
Run Up ◽  
Better Than

This study evaluates the capability of Navier–Stokes solvers in predicting forward and backward plunging breaking, including assessment of the effect of grid resolution, turbulence model, and VoF, CLSVoF interface models on predictions. For this purpose, 2D simulations are performed for four test cases: dam break, solitary wave run up on a slope, flow over a submerged bump, and solitary wave over a submerged rectangular obstacle. Plunging wave breaking involves high wave crest, plunger formation, and splash up, followed by second plunger, and chaotic water motions. Coarser grids reasonably predict the wave breaking features, but finer grids are required for accurate prediction of the splash up events. However, instabilities are triggered at the air–water interface (primarily for the air flow) on very fine grids, which induces surface peel-off or kinks and roll-up of the plunger tips. Reynolds averaged Navier–Stokes (RANS) turbulence models result in high eddy-viscosity in the air–water region which decays the fluid momentum and adversely affects the predictions. Both VoF and CLSVoF methods predict the large-scale plunging breaking characteristics well; however, they vary in the prediction of the finer details. The CLSVoF solver predicts the splash-up event and secondary plunger better than the VoF solver; however, the latter predicts the plunger shape better than the former for the solitary wave run-up on a slope case.

Detailed Study on Breaking Wave Interactions With a Jacket Structure Based on Experimental Investigations

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Jithin Jose ◽  
Olga Podrażka ◽  
Ove Tobias Gudmestad ◽  
Witold Cieślikiewicz
Keyword(s):  
Wind Turbines ◽  
Wave Breaking ◽  
Offshore Structures ◽  
Offshore Wind ◽  
Wave Forces ◽  
Breaking Wave ◽  
Offshore Wind Turbines ◽  
Wave Parameters ◽  
Wave Slamming ◽  
Breaking Wave Forces

Wave breaking is one of the major concerns for offshore structures installed in shallow waters. Impulsive breaking wave forces sometimes govern the design of such structures, particularly in areas with a sloping sea bottom. Most of the existing offshore wind turbines were installed in shallow water regions. Among fixed-type support structures for offshore wind turbines, jacket structures have become popular in recent times as the water depth for fixed offshore wind structures increases. However, there are many uncertainties in estimating breaking wave forces on a jacket structure, as only a limited number of past studies have estimated these forces. Present study is based on the WaveSlam experiment carried out in 2013, in which a jacket structure of 1:8 scale was tested for several breaking wave conditions. The total and local wave slamming forces are obtained from the experimental measured forces, using two different filtering methods. The total wave slamming forces are filtered from the measured forces using the empirical mode decomposition (EMD) method, and local slamming forces are obtained by the frequency response function (FRF) method. From these results, the peak slamming forces and slamming coefficients on the jacket members are estimated. The breaking wave forces are found to be dependent on various breaking wave parameters such as breaking wave height, wave period, wave front asymmetry, and wave-breaking positions. These wave parameters are estimated from the wave gauge measurements taken during the experiment. The dependency of the wave slamming forces on these estimated wave parameters is also investigated.

scholarly journals Computational Fluid Dynamics Simulation of Deep-Water Wave Instabilities Involving Wave Breaking

2021 ◽  
Vol 144 (2) ◽  
Author(s):  
Yuzhu Li ◽  
David R. Fuhrman
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Deep Water ◽  
Wave Breaking ◽  
Water Wave ◽  
Class Ii ◽  
Dynamics Simulation ◽  
Class I ◽  
Wave Instabilities ◽  
Deep Water Wave

Abstract Instabilities of deep-water wave trains subject to initially small perturbations (which then grow exponentially) can lead to extreme waves in offshore regions. The present study focuses on the two-dimensional Benjamin–Feir (or modulational) instability and the three-dimensional crescent (or horseshoe) waves, also known as Class I and Class II instabilities, respectively. Numerical studies on Class I and Class II wave instabilities to date have been mostly limited to models founded on potential flow theory; thus, they could only properly investigate the process from initial growth of the perturbations to the initial breaking point. The present study conducts numerical simulations to investigate the generation and development of wave instabilities involving the wave breaking process. A computational fluid dynamics (CFD) model solving Reynolds-averaged Navier–Stokes (RANS) equations coupled with a turbulence closure model in terms of the Reynolds stress model is applied. Wave form evolutions, Fourier amplitudes, and the turbulence beneath the broken waves are investigated.

Ocean Power Generator Using Flexible Piezoelectric Device

2013 ◽  
Author(s):  
Hidemi Mutsuda ◽  
Ryuta Watanabe ◽  
Shota Azuma ◽  
Yoshikazu Tanaka ◽  
Yasuaki Doi
Keyword(s):  
Electric Power ◽  
Wave Breaking ◽  
Strain Energy ◽  
Electrical Energy ◽  
Electric Polarization ◽  
Scale Model ◽  
Breaking Wave ◽  
Ocean Energy ◽  
Power Generator ◽  
Piezoelectric Device

We have developed a way of harvesting electrical energy from ocean power, e.g. tide, current wave, breaking wave and vortex, using a Flexible PiezoElectric Device (FPED) consisting of polyvinyledene fluoride (PVDF) and elastic material such as rubber, silicon and resin. The proposed FPED has a multi-layered structure with a distance δ between FPEDs located away from centerline of the FPED. When the FPED can be easily deformed by ocean power, the PVDF laminated in the FPED can be expanded and compressed and then the internal strain energy can be stored in the FPED. The electric power is generated when the electric polarization occurs in the PVDF. In this study, we have proposed an ocean power generator of EFHAS (Elastic Floating unit with HAnging Structures) consisting of floating unit and hanging unit using the FPEDs to obtain electric power from ocean energy. We investigated a structure of the EFHAS and also examined characteristics of motion and electric performance of the EFHAS (1/50–1/75 scale model. We made clear that the EFHAS could be useful as ocean power generator.

scholarly journals Non-breaking and breaking solitary wave run-up

2002 ◽  
Vol 456 ◽  
pp. 295-318 ◽  
Author(s):  
YING LI ◽  
FREDRIC RAICHLEN
Keyword(s):  
Numerical Model ◽  
Solitary Wave ◽  
Wave Breaking ◽  
Ad Hoc ◽  
Mapping Technique ◽  
Breaking Wave ◽  
Good Prediction ◽  
Computational Domain ◽  
Domain Mapping ◽  
Run Up

The run-up of non-breaking and breaking solitary waves on a uniform plane beach connected to a constant-depth wave tank was investigated experimentally and numerically. If only the general characteristics of the run-up process and the maximum run-up are of interest, for the case of a breaking wave the post-breaking condition can be simplified and represented as a propagating bore. A numerical model using this bore structure to treat the process of wave breaking and subsequent shoreward propagation was developed. The nonlinear shallow water equations (NLSW) were solved using the weighted essentially non-oscillatory (WENO) shock capturing scheme employed in gas dynamics. Wave breaking and post-breaking propagation are handled automatically by this scheme and ad hoc terms are not required. A computational domain mapping technique was used to model the shoreline movement. This numerical scheme was found to provide a relatively simple and reasonably good prediction of various aspects of the run-up process. The energy dissipation associated with wave breaking of solitary wave run-up (excluding the effects of bottom friction) was also estimated using the results from the numerical model.

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