scholarly journals FORMULATION AND APPLICATION OF FREQUENCY-DOMAIN NONLINEAR WAVE TRANSFORMATION MODEL INCORPORATING INCIDENT AND REFLECTED WAVE COUPLING

2006 ◽  
Vol 62 (3) ◽  
pp. 284-293
Author(s):  
Kazuhiko HONDA ◽  
Hajime MASE
Keyword(s):  
Frequency Domain ◽  
Nonlinear Wave ◽  
Transformation Model ◽  
Wave Transformation ◽  
Wave Coupling ◽  
Reflected Wave

Extreme Value Prediction on Decreasing Depth by Means of a Nonlinear Wave Transformation Model

2007 ◽  
Author(s):  
K. A. Belibassakis ◽  
Ch. N. Stefanakos ◽  
Y. G. Georgiou
Keyword(s):  
Time Series ◽  
Nonlinear Wave ◽  
Extreme Value ◽  
Second Order ◽  
Transformation Model ◽  
Wave Transformation ◽  
Series Data ◽  
Wave Spectra ◽  
Wave Parameters

In the present work a weakly nonlinear wave model originally developed by Rebaudengo Lando` et al (1996) is applied to the transformation of wave spectra from offshore to nearshore, and subsequently, it has been systematically applied to the derivation of long-term time series of spectral wave parameters on decreasing depth from corresponding offshore wave data. The derived long-term series of nearshore parameters have been used as input to a new method, recently developed by Stefanakos & Athanassoulis (2006), for calculating return periods of various level values from nonstationary time series data. The latter method is based on a new definition of the return period, that uses the MEan Number of Upcrossings of the level x* (MENU method), and it has been shown to lead to predictions that are more realistic than traditional methods. To examine the effects of bottom topography on the nearshore extreme value predictions, Roseau (1976) bottom profiles have been used for which analytical expressions are available concerning the reflection and transmission coefficients. A parametric (JONSWAP) model is used to synthesize offshore spectra from integrated parameters, which are then linearly transformed based on the previous transmission coefficient to derive first-order nearshore wave spectra. Second-order random sea states have been simulated by following the approach of Hudspeth & Chen (1979) (see also Langley 1987, Lando et al 1996), exploiting the quadratic transfer functions on decreasing depth to calculate the second-order nearshore spectra. Finally, wave parameters are extracted from the nearshore spectra by calculating the first few moments.

scholarly journals A MODEL IN FREQUENCY DOMAIN FOR TRANSFORMATION OF FULLY DISPERSIVE NONLINEAR WAVES

2018 ◽  
pp. 60
Author(s):  
Samira Ardani ◽  
James M. Kaihatu
Keyword(s):  
Frequency Domain ◽  
Evolution Equations ◽  
Wave Model ◽  
Multiple Scale ◽  
Transformation Model ◽  
Wave Transformation ◽  
Numerical Verification ◽  
Resonant Interactions ◽  
Dispersive Model ◽  
Mathematical Derivation

In this study, mathematical derivation and numerical verification of a wave transformation model in frequency domain is discussed. This wave model is fully dispersive and nonlinear; and is derived based on the WKB assumptions. Transforming the problem into the frequency domain and using multiple scale analysis in space and perturbation theory, the model is expanded up to second order in wave steepness. This fully dispersive nonlinear wave model is a set of evolution equations which explicitly contains quadratic near-resonant interactions. The comparison between the presented model, the existing fully dispersive model and a nearshore model with different set of laboratory and field data shows that the presented model provides significant improvements particularly at higher frequencies.

PHYSICAL INTERPRETATION OF WAVE BREAKING CRITERIA

2017 ◽  
Author(s):  
Sergey Kuznetsov ◽  
Sergey Kuznetsov ◽  
Yana Saprykina ◽  
Yana Saprykina ◽  
Boris Divinskiy ◽  
...  
Keyword(s):  
Nonlinear Wave ◽  
Wave Breaking ◽  
Second Harmonic ◽  
Vertical Axis ◽  
Breaking Waves ◽  
Wave Transformation ◽  
Spectral Structure ◽  
Similarity Parameter ◽  
Nonlinear Harmonics ◽  
The Waves

On the base of experimental data it was revealed that type of wave breaking depends on wave asymmetry against the vertical axis at wave breaking point. The asymmetry of waves is defined by spectral structure of waves: by the ratio between amplitudes of first and second nonlinear harmonics and by phase shift between them. The relative position of nonlinear harmonics is defined by a stage of nonlinear wave transformation and the direction of energy transfer between the first and second harmonics. The value of amplitude of the second nonlinear harmonic in comparing with first harmonic is significantly more in waves, breaking by spilling type, than in waves breaking by plunging type. The waves, breaking by plunging type, have the crest of second harmonic shifted forward to one of the first harmonic, so the waves have "saw-tooth" shape asymmetrical to vertical axis. In the waves, breaking by spilling type, the crests of harmonic coincides and these waves are symmetric against the vertical axis. It was found that limit height of breaking waves in empirical criteria depends on type of wave breaking, spectral peak period and a relation between wave energy of main and second nonlinear wave harmonics. It also depends on surf similarity parameter defining conditions of nonlinear wave transformations above inclined bottom.

Nonlinear Wave–Wave Coupling Related to Whistler-mode and Electron Bernstein Waves Observed by the Parker Solar Probe

2021 ◽  
Vol 918 (1) ◽  
pp. 26
Author(s):  
Jiuqi Ma ◽  
Xinliang Gao ◽  
Zhongwei Yang ◽  
Bruce T. Tsurutani ◽  
Mingzhe Liu ◽  
...  
Keyword(s):  
Nonlinear Wave ◽  
Wave Coupling ◽  
Whistler Mode ◽  
Bernstein Waves

scholarly journals Extended Elliptic Mild Slope Equation Incorporating the Nonlinear Shoaling Effect

2016 ◽  
Vol 23 (s1) ◽  
pp. 44-51 ◽  
Author(s):  
Qian-lu Xiao ◽  
Chun-hui Li ◽  
Xiao-yan Fu ◽  
Mei-ju Wang
Keyword(s):  
Dispersion Relation ◽  
Nonlinear Wave ◽  
Surf Zone ◽  
Wave Dispersion ◽  
Structure Design ◽  
Coastal Engineering ◽  
Wave Transformation ◽  
Flume Experiments ◽  
Mild Slope Equation ◽  
Wave Shoaling

Abstract The transformation during wave propagation is significantly important for the calculations of hydraulic and coastal engineering, as well as the sediment transport. The exact wave height deformation calculation on the coasts is essential to near-shore hydrodynamics research and the structure design of coastal engineering. According to the wave shoaling results gained from the elliptical cosine wave theory, the nonlinear wave dispersion relation is adopted to develop the expression of the corresponding nonlinear wave shoaling coefficient. Based on the extended elliptic mild slope equation, an efficient wave numerical model is presented in this paper for predicting wave deformation across the complex topography and the surf zone, incorporating the nonlinear wave dispersion relation, the nonlinear wave shoaling coefficient and other energy dissipation factors. Especially, the phenomenon of wave recovery and second breaking could be shown by the present model. The classical Berkhoff single elliptic topography wave tests, the sinusoidal varying topography experiment, and complex composite slopes wave flume experiments are applied to verify the accuracy of the calculation of wave heights. Compared with experimental data, good agreements are found upon single elliptical topography and one-dimensional beach profiles, including uniform slope and step-type profiles. The results indicate that the newly-developed nonlinear wave shoaling coefficient improves the calculated accuracy of wave transformation in the surf zone efficiently, and the wave breaking is the key factor affecting the wave characteristics and need to be considered in the nearshore wave simulations.

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