MULTIGRID TECHNIQUES FOR THE NUMERICAL SOLUTION OF THE DIFFUSION EQUATION

An accurate numerical solution of diffusion problems containing large local gradients can be obtained with a significant reduction in computational time by using a multi-grid computational scheme. The spatial domain is covered with sets of uniform square grids of different sizes. The finer grid patterns overlap the coarse grid patterns. The finite-difference expressions for each grid pattern are solved Independently by iterative techniques. Two interpolation methods were used to establish the values of the potential function on the fine grid boundaries with information obtained from the coarse grid solution. The accuracy and computational requirements for solving a test problem by a simple multigrid and a multilevel-multigrid method were compared. The multilevel-multigrid method combined with a Taylor series interpolation scheme was found to be best.