中文摘要：

块体滑坡往往引起自由水面的剧烈变化，研究块体滑坡激发的水面波动一直是水利与海岸工程界非常感兴趣的问题。该文使用SPH方法（光滑质点水动力学）对水下块体下滑引起的自由表面水动力学过程进行了二维数值模拟，并将数值计算结果与试验数据作了对比，计算结果给出了块体下滑过程中，水体表面出现的二次卷破现象，以及在块体上方出现两个方向相反的旋涡，显示了SPH方法对处理块体下滑引起的自由表面大变形问题具有十分优越的特性。通过数值试验，文中还讨论了滑块下滑速度对自由表面破碎和形成的旋涡个数的影响。

英文摘要：

Landslide-generated water waves have always been of great interest to hydraulic and coastal engineers because the large deformation and breaking of the free surface bring great challenges for theoretical and numerical studies. The two-dimensional underwater landslide is studied numerically by using the Smoothed Particle Hydrodynamics （SPH） method. Numerical examples show the computed results are in good agreement with the experimental ones. It demonstrated that SPH method can deal with the hydrodynamic flows generated by landslides in reservoir or coastal waters, and the SPH method has the superiority in simulating the phenomena of large deformation of the free surface. The simulation result shows the second plunging during the sliding of the box. Two vortices with opposite directions were observed above the box after it slide on the bottom of the numerical flume. The vortex will maintain for a long time even the water surface recovering to a calm surface. The effects of sliding velocity on the number of plunging and the number of vortex induced by landslides are discussed through numerical experiments.