scholarly journals Simple Wave Breaking Depth Index Formula for Regular Waves

2020 ◽  
Vol 146 (1) ◽  
pp. 06019001
Author(s):  
Giuseppe Roberto Tomasicchio ◽  
Sahameddin Mahmoudi Kurdistani ◽  
Felice D’Alessandro ◽  
Leila Hassanabadi
Keyword(s):  
Wave Breaking ◽  
Simple Wave ◽  
Index Formula ◽  
Regular Waves ◽  
Depth Index

scholarly journals NUMERICAL MODELLING OF BREAKER DEPTH INDEX

2017 ◽  
pp. 29
Author(s):  
Felice D'Alessandro ◽  
Giuseppe Tomasicchio ◽  
Giancarlo Chiaia ◽  
Francesco Ciardulli ◽  
Antonio Francone
Keyword(s):  
Experimental Investigation ◽  
Numerical Modelling ◽  
Wave Breaking ◽  
Large Scale ◽  
Fixed Bed ◽  
Wave Model ◽  
The Other ◽  
Regular Waves ◽  
Depth Index ◽  
Physical Data

The breaker depth index, γb, is commonly used to determine the wave height to water depth ratio where the wave will break (Horikawa, 1988). In the present study, γb has been calculated using a fully nonlinear Boussinesq Type Equations (BTE) wave model with implemented BCI (Breaking Celerity Index). The BCI is a phase-resolving type breaking criterion for calculating the incipient wave breaking conditions (D’Alessandro and Tomasicchio, 2008). The model suitability in predicting γb has been verified against physical data from an experimental investigation conducted with incident regular waves propagating along uniform 1:20 and 1:50 slope beaches (G.V. dos Reis, 1992), and estimates of γb from five existing empirical formulae (Battjes, 1974; Ostendorf and Madsen, 1979; Singamsetti and Wind, 1980; Smith and Kraus, 1990; Goda, 2010). The comparisons showed that BCI presents a better agreement with the physical data with respect to the other investigated formulae in determining the value of γb, independently from the breaker type. In addition, the verification of the BCI in determining γb has been extended to the observed data from a large-scale laboratory experiment on wave hydrodynamics performed over a fixed-bed barred beach (Tomasicchio and Sancho, 2002).

scholarly journals BREAKWATER ARMOR DISPLACEMENT THRESHOLDS: A POSSIBLE CORRELATION WITH CUMULATIVE WAVE ENERGY

1984 ◽  
Vol 1 (19) ◽  
pp. 186
Author(s):  
Daniel L. Behnke ◽  
Frederic Raichlen
Keyword(s):  
Wave Energy ◽  
Wave Train ◽  
Wave Length ◽  
Simple Wave ◽  
Wave Theory ◽  
Irregular Waves ◽  
Reconstruction Technique ◽  
Regular Wave ◽  
Regular Waves ◽  
Three Dimensional Model

An extensive program of stability experiments in a highly detailed three-dimensional model has recently been completed to define a reconstruction technique for a damaged breakwater (Lillevang, Raichlen, Cox, and Behnke, 1984). Tests were conducted with both regular waves and irregular waves from various directions incident upon the breakwater. In comparison of the results of the regular wave tests to those of the irregular wave tests, a relation appeared to exist between breakwater damage and the accumulated energy to which the structure had been exposed. The energy delivered per wave is defined, as an approximation, as relating to the product of H2 and L, where H is the significant height of a train of irregular waves and L is the wave length at a selected depth, calculated according to small amplitude wave theory using a wave period corresponding to the peak energy of the spectrum. As applied in regular wave testing, H is the uniform wave height and L is that associated with the period of the simple wave train. The damage in the model due to regular waves and that caused by irregular waves has been related through the use of the cumulative wave energy contained in those waves which have an energy greater than a threshold value for the breakwater.

scholarly journals The Interaction between Atmospheric Gravity Waves and Large-Scale Flows: An Efficient Description beyond the Nonacceleration Paradigm

2016 ◽  
Vol 73 (12) ◽  
pp. 4833-4852 ◽  
Author(s):  
Gergely Bölöni ◽  
Bruno Ribstein ◽  
Jewgenija Muraschko ◽  
Christine Sgoff ◽  
Junhong Wei ◽  
...  
Keyword(s):  
Steady State ◽  
Wave Breaking ◽  
Large Scale ◽  
Climate Models ◽  
Weather Prediction ◽  
Simple Wave ◽  
Mean Flow ◽  
Action Density ◽  
Total Energy Balance ◽  
Flow Interactions

Abstract With the aim of contributing to the improvement of subgrid-scale gravity wave (GW) parameterizations in numerical weather prediction and climate models, the comparative relevance in GW drag of direct GW–mean flow interactions and turbulent wave breakdown are investigated. Of equal interest is how well Wentzel–Kramer–Brillouin (WKB) theory can capture direct wave–mean flow interactions that are excluded by applying the steady-state approximation. WKB is implemented in a very efficient Lagrangian ray-tracing approach that considers wave-action density in phase space, thereby avoiding numerical instabilities due to caustics. It is supplemented by a simple wave-breaking scheme based on a static-instability saturation criterion. Idealized test cases of horizontally homogeneous GW packets are considered where wave-resolving large-eddy simulations (LESs) provide the reference. In all of these cases, the WKB simulations including direct GW–mean flow interactions already reproduce the LES data to a good accuracy without a wave-breaking scheme. The latter scheme provides a next-order correction that is useful for fully capturing the total energy balance between wave and mean flow. Moreover, a steady-state WKB implementation as used in present GW parameterizations where turbulence provides by the noninteraction paradigm, the only possibility to affect the mean flow, is much less able to yield reliable results. The GW energy is damped too strongly and induces an oversimplified mean flow. This argues for WKB approaches to GW parameterization that take wave transience into account.

scholarly journals Wave Breaker Types on a Smooth and Impermeable 1:10 Slope

2020 ◽  
Vol 8 (4) ◽  
pp. 296
Author(s):  
María Victoria Moragues ◽  
María Clavero ◽  
Miguel Á. Losada
Keyword(s):  
Wave Breaking ◽  
Research University ◽  
Research Study ◽  
Flow Characteristics ◽  
Experimental Tests ◽  
System Research ◽  
Energy Transformation ◽  
Regular Waves ◽  
Similarity Parameter ◽  
Complete Set

This research identified the types of wave breaker on a non-overtoppable, smooth and impermeable 1:10 slope under regular waves. Experimental tests were carried out in the Atmosphere-Ocean Interaction Flume of the Andalusian Institute for Earth System Research (University of Granada). Using the experimental space [log(h/L)–log(H/L)] and the alternate slope similarity parameter [χ = log (h/L H/L)], a complete set of breaker types was identified. Four types of wave breaker were then added to Galvin’s classification. Our results showed that the value of the Iribarren number was not sufficient to predict the expected type of wave breaker on the slope. Except for spilling and early plunging breakers, no biunivocal relationship was found between Ir and the type of breaker. The data obtained in the physical model were further enriched with the results of the flow characteristics and the wave energy transformation coefficients obtained with the IH-2VOF numerical model on a 1:10 impermeable slope. This research study, presented in this paper, showed that the Iribarren number is not a convenient wave breaking similarity parameter.

Sea Spectra Simplified

1968 ◽  
Vol 5 (01) ◽  
pp. 17-30
Author(s):  
Walter H. Michel
Keyword(s):  
Simple Wave ◽  
Regular Waves ◽  
Irregular Pattern ◽  
Irregular Behavior ◽  
Naval Architect

A dissertation on the simple wave elements that make up the complex sea, this paper is intended to give the practicing naval architect a clearer view of how regular waves combine into an irregular pattern and how the consequent irregular behavior of a vessel at sea can be predicted on the basis of recent statistical formulations.

scholarly journals Simple Breaker Index Formula Using Linear Model

2021 ◽  
Vol 9 (7) ◽  
pp. 731
Author(s):  
Kwang-Ho Lee ◽  
Yong-Hwan Cho
Keyword(s):  
Machine Learning ◽  
Linear Equation ◽  
Wave Breaking ◽  
Predictive Performance ◽  
Machine Learning Algorithms ◽  
Supervised Machine Learning ◽  
Index Formula ◽  
Empirical Formulas ◽  
Simple Linear Equation ◽  
Breaking Index

Breaking waves generated by wave shoaling in coastal areas have a close relationship with various physical phenomena in coastal regions. Therefore, it is crucial to accurately predict breaker indexes such as breaking wave height and breaking depth when designing coastal structures. Many studies on wave breaking have been carried out, and many experimental data have been documented. Representative studies on wave breaking provide many empirical formulas for the prediction of breaking index, mainly through hydraulic model experiments. However, the existing empirical formulas for breaking index determine the coefficients of the assumed equation through statistical analysis of data under the assumption of a specific equation. This study presents an alternative method to estimate breaker index using representative linear-based supervised machine learning algorithms that show high predictive performance in various research fields related to regression or classification problems. Based on the used machine learning methods, a new simple linear equation for the prediction of breaker index is presented. The newly proposed breaker index formula showed similar predictive performance compared to the existing empirical formula, although it was a simple linear equation.

Characterization of the Emergence of Rogue Waves From Given Spectra Through a Wigner Equation Approach

2018 ◽  
Author(s):  
Agissilaos G. Athanassoulis
Keyword(s):  
Wave Breaking ◽  
Modulation Instability ◽  
Simple Wave ◽  
Rogue Waves ◽  
Measured Spectrum ◽  
Equation Approach ◽  
Wigner Transform ◽  
Wigner Equation ◽  
Joint Work

The Wigner transform can be used to derive equations directly for the evolution of the autocorrelation of the sea elevation. This has been known in the literature as the derivation of the Alber equation, and applies to envelope equations. Wigner-Alber equations have been used to characterise spectra as either stable or unstable, and to predict Fermi-Pasta-Ulam recurrent dynamics for the unstable ones. Here we show that a systematic study of Wigner equations can improve this analysis in several respects, including: (i) the incorporation of accurate dispersion and (simple) wave breaking effects; and (ii) the characterization of the space and time scales over which localized extreme events emerge. More broadly this approach can be seen as a full modulation instability analysis for any measured spectrum. This work builds upon recent joint work with G. Athanassoulis and T. Sapsis.

scholarly journals TWO-PHASE ASYMPTOTICS IN THE FORM OF AIRY FUNCTIONS IN THE WAVE BREAKING PROBLEM FOR THE I-BURGERS EQUATION

2019 ◽  
Vol 47 (1) ◽  
pp. 41-42
Author(s):  
S.U. Dobrokhotov ◽  
V.E. Nazaikinskii
Keyword(s):  
Wave Breaking ◽  
Burgers Equation ◽  
Logarithmic Derivative ◽  
Simple Wave ◽  
Airy Functions ◽  
Two Phase ◽  
The Russian Federation ◽  
Small Dispersion ◽  
Oscillation Zone

We consider wave breaking problems for the Burgers equation with a small “imaginary viscosity,” which in fact plays the role of small dispersion. Although this equation has no apparent physical meaning, the problem in question is an interesting analog of the famous Gurevich-Pitaevsky problem on the onset of an oscillation zone as the breaking of a simple wave occurs for the Korteweg-de Vries equation. In contrast to the latter, the solution of the i-Burgers equation in the oscillation zone can be described explicitly and has a two-phase structure. This was indicated more than 25 years ago in (Dobrokhotov et al., 1992), where the solution was constructed in the form of a function of Maslov’s canonical operator. Now we use the recent results in (Dobrokhotov, Nazaikinskii, 2018) to present the solutions in the more efficient form of uniform asymptotics represented as the logarithmic derivative of the Airy function of a composite argument. The research was supported by the Ministry of Science and Higher Education of the Russian Federation (project no. AAAA-A17-117021310377-1).

scholarly journals Breaking-Wave Induced Transient Pore Pressure in a Sandy Seabed: Flume Modeling and Observations

2021 ◽  
Vol 9 (2) ◽  
pp. 160
Author(s):  
Changfei Li ◽  
Fuping Gao ◽  
Lijing Yang
Keyword(s):  
Pore Pressure ◽  
Wave Height ◽  
Wave Breaking ◽  
Breaking Waves ◽  
Breaking Wave ◽  
Regular Waves ◽  
Large Wave ◽  
Pore Pressures ◽  
Linear Waves ◽  
Wave Induced

Previous studies on wave-induced pore pressure in a porous seabed mainly focused on non-breaking regular waves, e.g., Airy linear waves or Stokes non-linear waves. In this study, breaking-wave induced pore pressure response in a sandy seabed was physically simulated with a large wave flume. The breaking-wave was generated by superimposing a series of longer waves onto the foregoing shorter waves at a specified location. Water surface elevations and the corresponding pore pressure in the process of wave breaking were measured simultaneously at three typical locations, i.e., at the rear, just at, and in front of the wave breaking location. Based on test results, characterization parameters are proposed for the wave surface elevations and the corresponding pore-pressures. Flume observations indicate that the wave height was greatly diminished during wave breaking, which further affected the pore-pressure responses. Moreover, the measured values of the characteristic time parameters for the breaking-wave induced pore-pressure are larger than those for the free surface elevation of breaking-waves. Under the action of incipient-breaking or broken waves, the measured values of the amplitude of transient pore-pressures are generally smaller than the predicted results with the analytical solution by Yamamoto et al. (1978) for non-breaking regular waves with equivalent values of characteristic wave height and wave period.

Sign in / Sign up

Export Citation Format

Share Document