基于双波群聚焦机制的畸形波生成机理分析  

Analysis of generation mechanism of freak waves based on two wave groups

作　　者：李金宣[1] 张亚荣 柳淑学[1] 王磊[1] LI Jin-xuan;ZHANG Ya-rong;LIU Shu-xue;WANG Lei(State Key Laboratory of Coastal and Offshore Engineering,Dalian University of Technology,Dalian 116024,China)

机构地区：[1]大连理工大学海岸和近海工程国家重点实验室,大连116024

出　　处：《水动力学研究与进展（A辑）》2020年第4期497-504,共8页Chinese Journal of Hydrodynamics

基　　金：国家自然科学基金(51739010,51879037);国家重点研发计划项目(2016YFC1401405,2016YFE0200100);中央高校基本科研业务费专项资金资助。

摘　　要：目前关于畸形波生成机理有多种假设,波群间的作用是畸形波产生的一个重要原因。该文利用两个单聚焦波群叠加,实验模拟了双波群聚焦产生畸形波的过程。通过小波分析、傅立叶变换和组成波分离等方法,分析了畸形波产生过程中波群的演化特征、频谱变化、波群间相互作用以及组成波的色散关系。研究发现在波群演化过程中,波群内部非线性作用较弱,而双波群间的三阶非线性作用显著,其对畸形波形成起到重要作用。并且波群谱峰频率宽度越小,三阶非线性作用越明显,这表明波群间频率宽度越小,越容易产生畸形波。There are many hypotheses about the mechanism of freak waves. The interaction between wave groups is an important reason for the generation of freak waves. In this paper, the superposition of two single-focused wave groups is used to simulate the process of freak waves generated by double-focused wave groups. By means of wavelet analysis, Fourier transform and separation of component waves, the evolution of wave properties, spectrum change, wave group interaction and dispersion relation of component waves are analyzed. It is found that in the process of wave group evolution, the non-linearity within the wave group is weak, while the third-order non-linearity between double wave groups is significant, which plays an important role in the formation of freak waves. Moreover, the smaller the frequency width of the wave group spectrum peak is, the more obvious the third-order nonlinear effect is, which indicates that in the wave train with smaller the frequency width, the freak wave will be more easily generated.

关 键 词：畸形波 双波群聚焦 频谱分析 三阶非线性相互作用 

分 类 号：U661.3[交通运输工程—船舶及航道工程]