NUMERICAL ASPECTS OF A BLOCK STRUCTURED COMPRESSIBLE FLOW SOLVER

A block structured compressible flow solver based on a finite volume a pproach with central spatial differencing is described and its perform ance in 2D on flow around an airfoil is studied. Variations in the num ber and dimensions of the blocks do not influence the convergence beha vior nor the solution, irrespective of the relative positions of a pos sible shock and the block-interfaces. Mixed calculations, in which the governing equations, either Euler or Reynolds averaged Navier-Stokes, differ per block, give accurate results provided the Euler blocks are defined outside the boundary layer and or in the far field wake regio n. Likewise, extensive grid distortions near block interfaces can be a llowed for outside the boundary layer. Finally, an unbalanced advancem ent in time, in which each block is advanced independently over severa l time steps gives no serious decrease in convergence rate.