Downwind numbering: a robust multigrid method for convection-diffusion problems on unstructured grids

In the present paper we introduce and investigate a robust smooting strategy for convection-diffusion problems in two and three space dimensions without any assumption on the grid structure. The main tool to obtain such a robust smoother for these problems is an ordering strategy for the grid points called ''downwind numbering'' which follows the flow direction and combined with a Gauss-Seidel type smoother yields robust multi-grid convergence for adaptively refined grids, provided the convection field is cycle free. The algorithms are of nearly optimum complexity and the corresponding smoothers are shown to be robust in numerical tests. (orig.)Available from TIB Hannover: RO 3493(1995,2) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman