Non-overlapping preconditioners for a parallel implicit Navier-Stokes solver

Parallel implicit iterative solution techniques are considered for application to a compressible hypersonic Navier-Stokes solver on unstructured meshes. The construction of parallel preconditioners with quasi-optimal convergence properties with respect to their serial counterpart is a key issue in the design of modern parallel implicit schemes. Two types of non-overlapping preconditioners are presented and compared. The first one is an additive Schwarz preconditioner requiring overlapping of the mesh and the second one departs from a Schur complement formulation. Both are using incomplete LU factorisation at the subdomain level but scale differently. Results are presented for computations on the Gray T3D under the message passing interface MPI.