Numerical Algorithms 0 ( 1998 ) ? { ? 1 A Hybrid Nonoverlapping Domain DecompositionScheme for Advection Dominated Advection - Di usionProblems

Two nonoverlapping domain decomposition algorithmsare proposed for convectiondom-inated convection-diiusion problems. In each subdomain, artiicial boundary conditions are used on the innow and outtow boundaries. If the ow is simple, each subdomain problem only needs to be solved once. If there are closed streamlines, an iterative algorithmis needed and the convergence is proved. Analysis and numerical tests reveal that the methods are advantageous when the diiusion parameter is small. In such cases, the error introduced by the domain decomposition methods is negligible in comparison with the error in the singular layers, and it allows easy and eecient grid reenement in the singular layers.