Implicit solution of preconditioned Navier-Stokes equations using algebraic multigrid

We describe an algorithm for the solution of the Navier-Stokes equations on unstructured meshes that employs a coupled algebraic multigrid method to a ccelerate a point-implicit symmetric Gauss-Seidel relaxation scheme. The eq uations are preconditioned to permit solution of both compressible and inco mpressible Bows. A cell-based, finite volume discretization is used in conj unction with Bus-difference splitting and a linear reconstruction of variab les. We present results for flowfields representing a range of Mach numbers and Reynolds numbers. The scheme remains stable up to infinite Courant num ber and exhibits CPU usage that scales linearly with cell count.