中文摘要：

主要研究了影响非定常动边界问题的一些基本参数并分析了其与推进力的关系。数值模拟采用格子波尔兹曼方法求解流场信息，并用浸入边界速度修正方法进行边界处速度的修正。研究对象为二维情况下摆动的鱼，影响推进力的参数有鱼体的形状、频率、波长、雷诺数。通过对各个参数的一系列模拟，得出其对推进力的不同影响关系。本文总共选取五种形状的鱼体，其运动模式为鱼体中线以行波的方式做横向摆动。最后，从涡的角度分析鱼的尾尖在不同位置时鱼体表面涡的分布情况，得到旋涡变化与鱼身运动的相互关系。通过研究发现，不同形状的鱼推进力不同，在高频、增大波长、增大雷诺数时，推进力增大。

英文摘要：

The current study mainly focuses on some fundamental parameters that affect the unsteady moving boundary problems.The relationships between the propulsion force and these parameters are ana-lyzed.To numerically simulate fish swimming in this work,the Lattice Boltzmann Method （LBM）is applied to obtain the information of flow field.At the same time,the velocity near the body is corrected via the Im-mersed Boundary Velocity Correction Method （IBVCM）.Here,a two-dimensional oscillating fish is studied and the factors affecting the fish swimming,which are investigated in current study,are the shape,frequen-cy,wavelength,and Reynolds number as well.After a series of simulations with different parameters,the correspondly effects on the propulsion force are obtained.Five kinds of shapes are selected for the fish body, and its motion mode is that the centerline of fish oscillates transversally in the form of traveling wave.More-over,from the perspective of vortex,the vortex distribution is analyzed with a set of locations on the fish tail tip,and therefore the relationship between the dynamics of vortex and fish motion is achieved.The investi-gation indicates that the propulsion force is different as fish shape changes,and higher frequency,wave-length,or Reynolds number produces higher propulsion force.