依据三类内孤立波理论KdV、eK dV和MCC的适用性条件,采用Navier-Stokes方程为流场控制方程,以内孤立波诱导上下层深度平均水平速度作为入口边界条件,建立了两层流体中内孤立波对张力腿平台强非线性作用的数值模拟方法。结果表明,数值模拟所得内孤立波波形及其振幅与相应理论和实验结果一致,并且在内孤立波作用下张力腿平台水平力、垂向力及力矩数值模拟结果与实验结果吻合。研究同时表明,张力腿平台内孤立波载荷由波浪压差力、粘性压差力和摩擦力构成,其中摩擦力很小,可以忽略;水平力的主要成分为波浪压差力和粘性压差力,粘性压差力与波浪压差力相比较小却不可忽略,流体粘性的影响较小;垂向力中粘性压差力很小,流体粘性影响可以忽略。
According to the applicability conditions for three types of internal solitary waves theories including KdV,eK dV and MCC,a numerical method based on the Navier-Stokes equation in a two-layer fluid is presented to simulate the strongly nonlinear interaction of internal solitary waves with a tension leg platform( TLP),where the velocity-inlet boundary is applied by use of the depth-averaged velocities in the upper and lower-layer fluids induced by the internal solitary waves. Results show that the waveforms and amplitudes of the internal solitary waves based on the present numerical method are in good agreements with the experimental and theoretical results,and that the numerical results for the horizontal and vertical forces,as well as torques on the TLP due to the internal solitary waves,have good agreement with experimental results. It is shown that the horizontal and vertical forces on the TLP due to the internal solitary waves can be divided into three components which are the wave and viscous pressure forces,as well as the fractional force,which is a small amount and hence can be neglected. For the horizontal force,its main components are wave pressure and viscous pressure forces.Compared with the wave pressure force,the viscous pressure force is small but can not be neglected. For the vertical force,the component of the viscous pressure force is a small amount and hence can be neglected.