基于相平均方法的折射绕射联合波浪模型

A COMBINED REFRACTION AND DIFFRACTION WATER WAVE MODEL USING PHASE-AVERAGED APPROACH

近岸带波浪运动的研究具有很重要的工程意义,近年来已获得了较丰硕的研究成果并发展了许多波浪模型,而基于不同理论的波浪模型往往具有特定的适用性.在海岸工程中应用比较广泛的一类波浪模型以波能(波作用量)守恒为基本依据,如SWAN模型.该类模型在实际工程中已经得到了大量的应用,但该类模型未计及波浪绕射效应,成为其突出的缺陷之一.如何对模型做适当的改进,使之适用于波浪绕射的模拟,从而在原有基础上拓广模型的应用范围是一项具有实际意义的研究工作.该文采用波能(波作用量)守恒方程描述近岸带波浪运动,通过引入绕射因子,得到折射、绕射联合波浪模型,从而拓广了模型的应用范围.通过实际算例验证,表明所建立的模型计及了波浪折射、绕射作用,对相平均波浪模型在波浪绕射效应模拟方面的改进具有一定的意义.

It is important in practical engineering to study the propagation of water waves in coastal waters using mathematical modeling methods.The research of water waves has progressed very much in the recent decades.Water wave models,such as mild-slope equation,Boussinesq equation and so on,have been put into practical engineering applications.But different water wave models have different effectiveness.The respective theoretical basis of the water wave models determines the features of these models.As mathematical models, based on the conversation law of wave energy or wave action,spectral wave models are used to determine wave conditions in coastal regions,which can account for all relevant processes of generation,dissipation and propagation.But the conventional spectral wave models can not simulate the wave diffraction.With diffraction being incorporated,the spectral wave models can be more widely used to simulate waves in the coastal regions. In this paper,a new phase averaged wave model is developed,in which the conservation of wave energy or wave action is used to formulate the wave propagation and a combined refraction and diffraction contribution is coupled through introducing a diffraction factor based on analysis of the mild slope equation.Computational results in extreme diffraction cases agree reasonably well with observations.It is shown that the new model can be used to simulate refraction and diffraction of water waves in coastal regions.