中文摘要：

为研究直立圆柱体的内孤立波载荷特性,依据三类内孤立波理论（Kd V、e Kd V和MCC）的适用性条件,使用内孤立波诱导上下层深度平均水平速度作为入口条件,采用Navier-Stokes方程为流场控制方程,建立了两层流体中内孤立波对直立圆柱体强非线性作用的数值模拟方法。系列计算结果表明,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,并且直立圆柱体内孤立波水平力、垂向力及其力矩数值模拟结果与实验结果吻合。直立圆柱体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;对水平力,其波浪压差力与粘性压差力量级相当,流体粘性的影响显著;对垂向力,粘性压差力很小,流体粘性影响可以忽略。

英文摘要：

In order to investigate the characteristics of loads on the vertical circular cylinder due to internal solitary waves a numerical method is studied. According to the applicability conditions for three types of internal solitary wave theories including Kd V,e Kd V and MCC,a numerical method based on the Navier-Stokes equation in a twolayer fluid is presented to simulate the strongly nonlinear interaction of internal solitary waves with a vertical circular cylinder,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 wave. The result showed that the waveform and amplitude of the internal solitary wave based on the present numerical method are in good agreement with the experimental and theoretical results. Numerical results for the horizontal and vertical forces,as well as torques on the vertical circular cylinder due to the internal solitary wave are also in good agreement with experimental results. It is shown by a series of calculations that the horizontal and vertical forces on the vertical circular cylinder can be divided into three components,including the wave and viscous pressure forces due to solitary waves. The friction force can in addition be neglected when the fraction force is a small amount. For the horizontal force,the order of the magnitude between the wave and viscous pressure forces is the same,which means the effect of the fluid viscosity is significant. For the vertical force,the component of the viscous pressure force is a small amount,which indicates that the effect of the fluid viscosity can be neglected.