复杂地形下海浪数值模式的特征线计算格式

Characteristics Computational Scheme of Numerical Wave Model Under Complex Topography Conditions

LAGFD-WAM海浪数值模式是一种第三代海浪数值模式,通过求解波数谱平衡方程,并考虑风输入、波浪破碎耗散、底摩擦耗散、波波非线性相互作用和波流相互作用等源函数,模拟波数空间下的海浪方向谱,并依此获得海浪的波高、周期和平均波向。该模式的一个显著特点是采用特征线嵌入格式求解海浪的传播。在进行浅水区域的海浪模拟时,特征线嵌入格式的数值计算方案是否合理对海浪数值模拟结果产生直接的影响。为此LAGFD-WAM海浪数值模式提出了一种新的特征线混合数值计算格式,并应用于浅水海浪数值模拟。结果表明,采用该计算方法,能够使数值模拟结果与实测结果很好符合。

The LAGFD-WAM numerical wave model is a third generation numerical wave model. In this model, the wave direction spectrum in wave number space is simulated by solving the wavenumber spectrum balance equation and taking into consideration the wind input, wave breaking dissipation, bottom friction dissipation, wave-wave interaction and wave-current interaction source functions, and the wave height, wave period and mean wave direction are then obtained. One of the significant features of this model is that the characteristics inlaid scheme is used to find the wave propagation solution. In simulating the wave in shallow water area, the rationality of numerical procedure with characteristics inlaid scheme will directly affect the numerically simulated results of wave. Therefore, a new mixed characteristics numerical computational scheme is proposed for the LAGFD-WAM numerical wave model and is applied in simulating the shallow water wave in this paper. It is shown from the computed results that the results simulated by using the new computational scheme are well consistent with the observed data.