Parallel FAS Multigrid for Arbitrary Mach Number,
High Reynolds Number Unstructured Flow Solvers

Daniel G. Hyams, Kidambi Sreenivas, David L. Whitfield
The University of Tennessee at Chattanooga, Chattanooga, Tennessee, 37403

A FAS multigrid capability has been developed in conjunction with a fully parallel Reynolds averaged Navier-Stokes solution algorithm, capable of efficiently simulating flows with mixed high speed (Mach number > 1) and low speed (Mach number < 0.01) flow regimes. Unique features of this multigrid approach include 1) fully general parallel agglomeration routines that are independent of the parallel subdomain layout, and 2) novel agglomeration procedures designed to take the high aspect ratio control volumes in the boundary layer into account. This multigrid algorithm has been applied to several aerodynamic geometries of interest and validated against experimental results. The performance of the multigrid code has been investigated and is shown to provide significant improvements in solution convergence.