变浅作用下浅水海浪谱的计算

深水海浪向近岸传播过程中,由于变浅作用,其波面高度分布,波谱都发生了变化。本文基于非线性系统的输出和输入间亦存在转换关系,通过波面高度分布函数建立了深水正态海浪过程作为输入和浅水偏态海浪过程作为输出之间的非线性转换关系,导出了深、浅水谱间的理论关系。在假定能通量不变的条件下,提出了一种由已知深水谱和波面偏度计算二维海浪变浅作用下的浅水谱的方法,并对其进行了讨论和检验。

Computation of the Shallow Water Spectrum under Shoaling Effect

In the course of the propagation of deep water waves to the shoal water zone, the distribution of the surface elevation and the wave spectrum will be changed due to shoaling effect. In this paper, on the basis of such a transfer relationship existing between the input and the output in a nonlinear system, the nonlinear transfer function between the input referring to the Gaussian process of the deep water wave and the output referring to the non-Gaussian process of the shallow water wave is established with the distributions of the surface elevation, and then the theoretical relationship between the deep water spectrum and the shallow water spectrum is derived. On the assumption of conservation of energy flux, a method of calculating the shallow water spectrum is presented by the given deep water spectrum and skewness of the surface elevation. The method proposed in this paper is discussed and verified by observations.