基于三类生成机理的畸形波运动特性及其与波形的关联机制

The wave load induced by Freak waves are controlled by the kinematics including phase velocity and water particle velocity. Then the kinematics are related to the Freak waves disasters directly. While there are only few knowledge about the Freak wave kinematics since the general definition for Freak waves only focusing on the wave height without the consideration of kinematics. And the observation approaches for extreme wave kinematics are limited. .Firstly, the generation processes of different kinds of Freak waves will be simulated by use a phase-resolved numerical mode based on High Order Spectra Method. Then the reconstruction approaches of Freak waves induced by self-focusing, wave-current interaction and wind input will be investigated in a numerical wave tank. Secondly, based on a nonlinear self-adjustment procedure, the Freak waves with same wave height series while different dynamic mechanisms will be performed and the measurement systems for kinematic parameters will be established. Thirdly, the kinematic characteristics of Freak waves, which are generated by different mechanisms, will be compared and analyzed based on both the numerical and experimental results. Then, the intrinsic relations among the kinematics and profiles of Freak waves will be investigated theoretically. Lastly, a new definition for Freak waves will be introduced by the addition consideration of wave profiles. This new definition is more suitable for practical application. .This research is addressed on the kinematics of Freak waves induced by three different kinds of generation mechanisms and the intrinsic relation to the wave profiles.The research output will extend the knowledge for Freak wave kinematics, particularly, for the differences among different kinds of Freak waves. It will provide more straightforward information for the further study of Freak waves’ prediction, prevention and reduction.

包含传播速度和水质点速度在内的畸形波运动特性，决定了波浪载荷大小，与畸形波灾害密切相关。但由于常用畸形波定义仅和波高有关，不考虑运动特性的影响，且对极端波浪速度场的观测手段有限，导致人们对畸形波运动特性的认识不足且重视不够。. 本研究将建立考虑水流和风作用的非线性数值波浪水槽，复演水波自聚焦、逆向流堆积和风驱作用三类机理下的畸形波形成过程，探讨生成机制不同波高相同的畸形波重构策略；基于非线性自调整聚焦方法，实现各类畸形波的实验室重构与运动参数量测；对比各类畸形波运动学参数与波形特征，探讨其关联机制；提出基于波高和波形双重指标的应用型畸形波定义。. 本研究旨在通过对三类机理下畸形波运动特性的认识，揭示其与波形的关联机制，拓展人们对畸形波运动特性，特别是各类畸形波运动差异性的认识，为将来进一步研究畸形波致灾机制、预测预报及防灾减灾提供较为直接的理论基础。

围绕畸形波重构策略，基于水槽物理模型实验分析了波浪在水槽内能量衰减的物理机制并提出波浪沿程衰减系数与厄塞尔数的经验关系式，并提出了一种测量水质点运动的示踪方法，建立能够同步获取波浪波形、传播速度和波峰水质点速度的实验量测系统，畸形波的波峰水质点速度测量得到验证。同时，为研究地形对波浪聚焦的影响，在实验室中设置周期性起伏地形实现了超谐波与次谐波共振的实验室现象重构，揭示了第三类布拉格共振激发波浪沿空间的演化过程，明确了第三类布拉格共振的激发条件所满足的波波非线性相互作用理论，并将第 III 类波浪布拉格共振的数值模拟结果和物理模型实验的结果进行对比验证。通过高阶谱方法建立模拟波浪非线性运动、波浪与地形相互作用的数值模型，数值模拟结果与物理实验结果进行对比验证。基于实验验证合理的高阶谱数值模型，对比了两种不同非线性自聚焦机制下生成畸形波波峰水质点运动特性的差异，并给出波峰高度与水质点速度之间的联系。通过模拟窄谱初始随机波浪场演化过程，发现畸形波波高极值主要影响因素为初始波陡，畸形波发生概率整体上随着 BFI 初值的增加而增加，主要影响因素为初始谱宽。围绕实际海洋中风场及地形对涌浪传播演化的影响，通过利用 CCMP 风场和 Holland 台风模型计算合成的合成风场驱动第三代海浪模式 WAVEWATCH III，对真实地形及理想地形下的四种典型台风生成涌浪，明确了东海涌浪在 4 种典型台风条件下及全年各季度的波高演变特性，并进行涌浪追踪，得出了上述台风条件及全年范围内涌浪的时空来源。通过移除影响涌浪传播的台湾岛及琉球岛链地形，利用理想地形及真实地形下涌浪波高数值的对比，探索了地形对于涌浪传播的影响。