连续分层流体中自由表面假定下内波传播的数值模拟

Numerical Simulation of Internal Wave Propagation in Density-Continuously Stratified Ocean under Assumption of Free Surface

针对密度连续分层的海域,基于Euler方程,采用改进的SIMPLE算法建立了考虑自由表面变化的内波传播数值模型。推导了自由表面边界条件下小振幅内波传播的理论解,并给出了刚盖假定下密度场的表达式。将自由表面和刚盖假定两种表面条件下的数值模拟的速度场和密度场进行比较,分析入射波特征参数,如周期和振幅,以及密度系数的影响。研究表明,在密度分层明显的海域中,对振幅较大的内波传播应采用自由表面边界条件进行模拟计算。

A numerical model of propagation of internal wave in density-continuously stratified ocean was provided under the assumption of free surface.In this model,the Euler equation was employed as the governing equation and discredited with the improved SIMPLE algorithm.Theoretical solution for the propagation of internal wave under the assumption of free surface was derived,and expression of the density field under the assumption of rigid lid was provided.Velocity fields computed under the assumption of free surface were compared with those under the assumption of rigid lid.Effects of parameters of incident waves such as period and amplitude,and coefficient of density on the velocity fields and density fields were discussed.It is concluded that the condition of the free surface should be adopted for the propagation of internal wave with large amplitude in the density-significantly stratified ocean field.