数值波浪序列中的高频成分

可靠的波浪模拟方法对于海洋结构物水动力性能的评估而言至关重要。文章基于软件FLUENT，分别采用四种不同的网格模型，实现了对于规则波的模拟。文中采用VOF方法对自由液面进行捕捉，并采用动网格方法模拟摇板的运动从而实现造波。考虑到数值耗散及截断误差对数值模拟结果的影响，针对沿水池方向的波浪衰减情况进行了相关研究。为了避免造波板的初始运动所引起的波面扰动，引入了一种“缓入”方法使造波板缓慢地达到最大幅值的运动，有效地避免了初始扰动所带来的影响。数值模拟的结果分别与一阶和二阶理论解进行了对比。结果表明，该数值波浪模型能够给出可靠的预测，为下一步模拟强非线性波浪（如畸形波）奠定了基础。

High-Frequency Components in Numerical Wave Trains

The reliability and repeatability of modelling waves is of great importance for the estima-tion of hydrodynamics of offshore structures. In this study, the commercial software package Fluent is used to simulate regular waves in four different mesh conditions. The free surface is captured using the Volume of Fluid (VOF) method. Dynamic mesh method is used to realize the flap-type wave-maker motion. Given the numerical dissipation and truncation errors during numerical simulations, wave decay along the tank is checked and controlled within a reasonable range. To avoid distur-bances induced by the starting of the flap movement, a fade-in method is adopted at the first 4 sec simulation. Regular waves are generated and compared with linear wave theory results and second-order wave theory results, respectively. The results show that the developed model based on VOF technique is able to provide reliable predictions. This developed model is expected to serve as a ba-sis for strongly nonlinear waves, such as freak waves.