A Multigrid Algorithm for a Multiblock Pressure-Based Flow and Heat Transfer Solver

A multigrid algorithm is developed along with an implicit multiblock pressure-based solver for calculating flow and heat transfer problems on nonorthogonal grids. The implicit treatment of the block interface has proven to be important for the efficiency of a multiblock method. In this study, the implicitness is adopted for all grid levels during a multigrid solution process. As a result, the block interface becomes invisible in the final solutions and the convergence is not adversely affected. The proposed multiblock multigrid algorithm is demonstrated on several representative two-dimensional flow and heat transfer problems. The results show that order-of-magnitude saving in computational time can be achieved with the multigrid algorithm.