随机波背景下基于NLSE模型的极端波分析

Analysis of extreme waves based on NLSE model under background of random waves

该文采用非线性薛定谔方程(NLSE)模拟极端波的形成与演化,利用NLSE呼吸子解理论上的频谱特征研究极端波的可预测性。为探究NLSE呼吸子解的频谱预测特性在接近真实海况下是否依旧适用,选取NLSE一阶呼吸子解作为极端波模型,基于JONSWAP谱的随机波作为背景波,将两者线性叠加,构造了具有随机背景波的极端波模型。并通过数值水池模拟叠加波面的演化,结果显示:在随机波成分占比不高时,含有背景波的合成波演化过程中,仍然保持呼吸子形成极端波的主要频谱特征,但随机成分可能会破坏极端波的形成,且频谱预测特征的显现与极端波的形成存在正相关性。

The nonlinear Schr?dinger equation(NLSE)model is widely used in the study of extreme waves,and the NLSE Peregrine breathing(PB)solution has theoretically predictable spectral properties.In order to investigate whether the spectral property of the PB solution remains valid for the near-real sea state,in present paper JONSWAP random wave is introduced as a background wave.The linear superposition of the two is used to construct a superposition extreme wave model that considers random wave background.A numerical wave tank is used to simulate the evolution of the superposition wave profile.The results show that the superposition model considering the random wave component maintains the main evolutionary features of the large waves formed by the PB model,given that the background wave is not high.The random component may break the formation of extreme waves,and there is a positive correlation between the spectral predictive features and the formation of extreme waves.