中文摘要：

利用多重网格虚拟边界有限元法（multigrid fictitious boundary method，MFBM），对粘性流场中固体颗粒的启动和沉降过程进行直接数值模拟。在计算过程中，计算网格是固定的多重结构有限元网格，固体颗粒可自由通过网格而无需重新生成网格。流体运动由Navier-Stokes方程控制，固体颗粒运动由Newton-Euler方程控制，用MFBM处理流体与固体颗粒的相互作用。通过对单个固体颗粒和多个固体颗粒启动和沉降过程的数值模拟，表明MFBM提供了一个数值模拟颗粒启动和沉降问题非常有效的途径。

英文摘要：

An efficient multigrid fictitious boundary method （MFBM） for the detailed simulation of the sedimentations and lift - off of rigid particles in viscous flows is presented in this paper. The calculation is carried on a fixed muhigrid finite element mesh on which fluid equations are satisfied everywhere, and the rigid particles are allowed to move freely through the mesh. The motion of the rigid particle is modeled by the Newton - Euler equations. Numerical experiments are presented to show that the presented MFBM provides a robust and efficient approach to directly simulate the sedimentations and lift - off of rigid particles in viscous flows.