波浪破碎的一种混合湍流模拟模式

A HYBRID TURBULENCE MODEL FOR WAVE BREAKING SIMULATION

近岸波浪的变形与破碎,一方面影响水体与泥沙运输,另一方面对消波护岸具有指导意义.本文提出一种三维混合湍流模拟模式方法,将求解区域分为造波区、波浪传播区和消波区.造波区采用层流模式,通过基于Fluent的二次开发的UDF方法在边界进行速度造波.这种方法在给定入口速度的条件下,根据已知波高进行精准插值,从而控制水的体积分数.在波浪传播区域,采用大涡模拟进行模拟研究,在消波区,采用RANS模型并利用多孔介质消波法进行消波.模型通过VOF方法捕捉波浪破碎过程中的自由面变化.本文对波高为5.5 cm的规则波(M1)、波高为13.5cm的规则波(M3)、有效波高为7.75cm的TMA谱单向不规则波(U1)和有效波高为19cm的TMA谱多向不规则波(B5)展开了模拟研究,并与前人的相关实验结果作比较,各条件下模拟结果与实验结果吻合.模拟结果说明本文提出的模型能够准确模拟出波浪传播过程中的折射和绕射现象,并且能够捕捉的波浪破碎过程中的自由面变化,为三维波浪的传播与破碎的数值模拟提供一种模拟方法.

On the one hand,the deformation and breaking of near-shore waves affect the transportation of water and sediment,and on the other hand,it is of guiding significance for wave elimination and revetment.In this paper,a 3-dimensional hybrid turbulence simulation model is proposed.Laminar flow mode is adopted in the wave-making region,and velocity wave-making is carried out at the boundary through the User Defined Function(UDF)developed based on fluent.This method can control the volume fraction of water by precise interpolation according to the known wave height under the condition of given inlet velocity.In the wave propagation region,large eddy simulation(LES)is used for simulation research,and in the wave elimination region,RANS model with the porous media wave absorber is used for wave elimination.The model uses the VOF method to capture the free surface changes in the process of wave breaking.This paper carried out simulation studies on the regular wave(M1)with a wave height of 5.5 cm,the regular wave(M3)with a wave height of 13.5 cm,the unidirectional irregular wave(U1)with a TMA spectrum with an effective wave height of 7.75 cm and the multidirectional irregular wave(B5)with an effective wave height of 19 cm.Simulation results show that the proposed model can accurately simulate the wave propagation in the process of refraction and diffraction phenomenon,and be able to catch the waves of the free surface in the process of change,broken for 3 D wave propagation and broken numerical simulation provides a method of simulation.