DOMAIN DECOMPOSITION ALGORITHMS for COMPRESSIBLE EULER's and N. S. EQUATIONS on UNSTRUCTURED MESHES Xiao-Chuan Cai Department of Computer Science University of Colorado at Boulder Charbel Farhat Department of Aerospace Engineering University of Colorado at Boulder Marcus Sarkis Department of Computer Science University of Colorado at Boulder In this presentation, we shall discuss recent results on the use of overllaping Schwarz methods for the numerical solution of steady and time-dependent compressible Euler and Navier-Stokes equations. The partial differential equations are discretized by a combined finite element/finite volume methods on unstructured meshes and using a MUSCL method. Several simulations are reported to compare the performance of domain decomposition preconditioners for different geometries and regime flows.