Composite Grid Method and Its Application on Seepage Problem

Composite grid method is a new technique developed in recent years for solving large-scale computation. Two different scale grids are used: a coarse mesh for the whole area without considering the impact of singularity and a fine mesh for the local singular area considering the impact of singularity respectively. The method solves the global coarse mesh problem and the local fine mesh problem iteratively and obtains the final result. As the mesh generation is more flexible and is mutually unrestricted, so the method is suitable for solving problem of source term moving with time. Compared with ordinary finite element method, the calculated examples show that it can improve the modeling accuracy, and reduce the calculated cost used in seepage problem. The method has an automatic adapting function and is convenient for parallel computing programs.