Modeling of liquid-solid flows with large number of moving particles by multigrid fictitious boundary method

An efficient multigrid fictitious boundary method (MFBM) for the detailed simulation of solid-liquid flows with large number of moving particles is presented. The MFBM is based on a multigrid FEM background grid which covers the whole computational domain and can be chosen independently from the particles of arbitrary shape, size and number. An obvious advantage of the MFBM is that it is able to efficiently treat the interaction between the fluid and the moving rigid particles, especially a fixed multigrid mesh is allowed to be used and there is no need to remesh. Two examples of numerical simulations of three big disks plunging into 2000 small particles as well as sedimentation of 5,000 particles in a cavity are provided to show that the presented method is potentially powerful to simulate real particulate flows with large number of moving particles.