海浪外观统计与内部结构关系的数值研究

基于数值模拟的三维随机海面,从时间域和空间域两个角度对海浪的外观特征和内部结构间的关系进行了研究,得出了一些在工程应用上有参考价值的结果.文章认为,将波面看作是若干随机正弦波叠加的海浪结构模型,用于描述平稳、均匀和窄谱的海况时,其频谱分析结果与外观统计结果基本上是一致的;但是,当海面处于谱宽度较大的风浪或混合浪状态时,一些频谱分析结果必须经过修正才能应用.同一海况下,海面波动的时间过程和沿主波向的空间分布是明显不同的.当海面有突发性大浪时,外频谱能够很好地反映不平稳海况,而频谱则把这种不平稳性平滑了.文章着重讨论了波长和波陡的计算、频谱和外频谱的差异.

A NUMERICAL STUDY ON RELATIONSHIP BETWEEN SEA WAVE APPARENT STATISTICS AND INTER STRUCTURE

Based on the three-dimensional stochastic sea surface by numerical simulation, a study on the relationship between sea wave apparent statistics and inter structure was carried out at the angles of both time and space, and some reference results valuable for engineering application were obtained. In the paper, wave surface was regarded as the wave structure model superposed by several sine waves. It is good for describing stable, uniform and narrow spectrum sea state, and its frequency spectrum analytical results basically agree with apparent statistic results. However, when sea surface is in a state of wind wave with wider spectrum or mixed wave, some frequency spectrum analytical results should be corrected beforeapplication. In the same sea state, the time process and the space distribution along major wave direction of the sea surface wave are apparently different. When it is abrupt rough sea, outer frequency spectrum can reflect the unstable sea state well, while this instability is smoothed by frequency spectrum. The paper focuses on the computation of wavelength and steepness as well as the difference between frequency spectrum and outer frequency spectrum.