SEGMENTED DOMAIN DECOMPOSITION MULTIGRID SOLUTIONS FOR 2-DIMENSIONAL AND 3-DIMENSIONAL VISCOUS FLOWS

Several viscous incompressible two and three-dimensional flows with st rong inviscid interaction and/or axial flow reversal are considered wi th a segmented domain decomposition multigrid (SDDMG) procedure. Speci fic examples include the laminar flow recirculation in a trough geomet ry and in a three-dimensional step channel. For the latter case, there are multiple and three-dimensional recirculation zones. A pressure-ba sed form of flux-vector splitting is applied to the Navier-Stokes equa tions, which are represented by an implicit, lowest-order reduced Navi er-Stokes (RNS) system and a purely diffusive, higher-order, deferred- corrector. A trapezoidal or box-like form of discretization insures th at all mass conservation properties are satisfied at interfacial and o utflow boundaries, even for this primitive-variable non-staggered grid formulation. The segmented domain strategy is adapted herein for thre e-dimensional flows and is extended to allow for disjoint subdomains t hat do not share a common boundary.