A Numerical Study on the Evolution of Random Seas With the Occurrence of Rogue Waves

2021 ◽  
Author(s):  
Zhuowei Zhou ◽  
Ningchuan Zhang ◽  
Guoxing Huang
Keyword(s):  
Numerical Study ◽  
Rogue Waves ◽  
Random Seas

scholarly journals A NUMERICAL STUDY OF FREAK WAVE GENERATION IN RANDOM SEAS OVER A SUBMERGED BAR

2018 ◽  
pp. 2
Author(s):  
Yuxiang Ma ◽  
Ruili Fu ◽  
Guohai Dong ◽  
Qiannan Du
Keyword(s):  
Numerical Study ◽  
Wave Model ◽  
Rogue Waves ◽  
Generation Process ◽  
Random Waves ◽  
Freak Waves ◽  
Higher Harmonics ◽  
Severe Accidents ◽  
Random Seas ◽  
Submerged Bar

Freak waves, also called rogue waves and giant waves, are much larger and steeper than the surrounding waves, can cause severe accidents, and can be formed in both coastal and offshore regions. The past researchers on freak waves in coastal regions are mainly focused on the statistical properties, and the generation mechanism of such large waves are not yet discussed intensively. The aim of the present study is to examine the generation process of freak waves in unidirectional propagating random waves over a submerged bar using a fully nonlinear numerical wave model, SWASH. It was found that freak waves are readily formed at the seaward part of the crest of the bar and gradually emerged from an intense wave group. The enhancement of the bound higher harmonics in the shoaling process is the main reason to form such large waves in shallow water. On the crest bar of the bathymetry, the extreme wave gradually vanished, mainly due to the releasing of bound higher-harmonics to free wave components.

A Numerical Study on the Evolution of Random Seas With the Occurrence of Rogue Waves

2021 ◽  
Author(s):  
Zhuowei Zhou ◽  
Ningchuan Zhang ◽  
Guoxing Huang
Keyword(s):  
Numerical Study ◽  
Rogue Waves ◽  
Random Seas

scholarly journals Breather Rogue Waves in Random Seas

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
J. Wang ◽  
Q. W. Ma ◽  
S. Yan ◽  
A. Chabchoub
Keyword(s):  
Rogue Waves ◽  
Random Seas

Numerical study of the energy structure of super rogue waves

2016 ◽  
Vol 113 ◽  
pp. 295-307 ◽  
Author(s):  
Wenyue Lu ◽  
Jianmin Yang ◽  
Longbin Tao
Keyword(s):  
Numerical Study ◽  
Rogue Waves ◽  
Energy Structure

Numerical study of Rogue waves as nonlinear Schrödinger breather solutions under finite water depth

Wave Motion ◽  
2015 ◽  
Vol 52 ◽  
pp. 81-90 ◽  
Author(s):  
Zhe Hu ◽  
Wenyong Tang ◽  
Hongxiang Xue ◽  
Xiaoying Zhang
Keyword(s):  
Water Depth ◽  
Numerical Study ◽  
Rogue Waves ◽  
Nonlinear Schrödinger ◽  
Finite Water Depth

A Numerical Study on the Evolution of Random Seas With the Occurrence of Rogue Waves

2021 ◽  
Vol 143 (5) ◽  
Author(s):  
Zhuowei Zhou ◽  
Ningchuan Zhang ◽  
Guoxing Huang
Keyword(s):  
Numerical Study ◽  
Wave Model ◽  
Rogue Waves ◽  
Experimental Investigations ◽  
Random Wave ◽  
Initial State ◽  
Incoming Wave ◽  
Spectral Parameters ◽  
Excess Kurtosis ◽  
Wave Trains

Abstract Numerous numerical and experimental investigations show that rogue waves present much larger probabilities of occurrence than predicted by the linear random wave model, i.e., Gaussian distributed waves. The deviation from normal statistical events excites a continuous concern about rogue wave research. In this study, rogue waves under long-crested and narrow-banded wave trains are checked using the high-order spectral (HOS)-NST model. The JONSWAP wave spectra with random phases are selected as the initial state of the incoming wave trains. Different values of spectral parameters are chosen to reproduce different random sea states with different Benjamin–Feir index (BFI). Numerical results are compared with the classical experimental study and show good agreements. Statistical properties of rogue waves are recounted again within the analysis of exceedance distribution function (EDF) of wave heights and wave crests. Spectral changes are examined, and the monotonic increases with BFI are stressed. However, no bifurcations are observed for BFI near 1. For large BFI, quasi-resonance interactions dominate the wave nonlinearities, and the resulted dynamic excess kurtosis involves initially monotonic enhancement along with space, peaking at around 20–30 wavelengths, but stays at stably high-level values. The quasi-steady-state of dynamic excess kurtosis after full interaction of wave nonlinearities in time and space demonstrates a continuous emergence of rogue waves much more frequent than normality. The changes of excess kurtosis along x are complicated where BFI near 1 and the occurrence of rogue waves might be enhanced even for BFI slightly inferior to 1.

Numerical study of the generation and evolution of breather-type rogue waves

2016 ◽  
Vol 12 (1) ◽  
pp. 66-76 ◽  
Author(s):  
Wenyue Lu ◽  
Jianmin Yang ◽  
Shixiao Fu
Keyword(s):  
Numerical Study ◽  
Rogue Waves

Optimal Design of Semisubmersible Form by Minimizing its Motion in Random Seas

1984 ◽  
Vol 106 (1) ◽  
pp. 23-30 ◽  
Author(s):  
S. Akagi ◽  
K. Ito
Keyword(s):  
Optimal Design ◽  
Numerical Study ◽  
Design Method ◽  
A Priori ◽  
Working Environment ◽  
Programming Technique ◽  
Random Seas ◽  
Optimal Design Method ◽  
Heave Motion ◽  
Sea Wave

For the purpose of improving the utilization of semisubmersibles such as oil rigs in random seas, an optimal design method is proposed to seek optimal forms with minimum motion against sea wave. In the optimal design method proposed here, the design objective is chosen to minimize the variance of heave motion amplitude of a semisubmersible oscillated by the sea wave in a working environment. By giving the displacement and the hull length of the semisubmersible as design conditions a priori, diameters of both hulls and each columns are determined optimally by using the quadratic programming technique. Through a numerical study on a semisubmersible design problem, it is ascertained that by the optimal design method a considerable improvement of the motion performance can be attained compared with the result given by the conventional design method.

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