A GENERAL ALGORITHM FOR COMPRESSIBLE AND INCOMPRESSIBLE-FLOW - STABILITY ANALYSIS AND EXPLICIT TIME INTEGRATION

Addresses two difficulties which arise when using a compressible code with equal order interpolation (non-staggered grids in the finite-diff erence nomenclature) to capture a steady-state solution in the incompr essible limit, i.e. at low Mach numbers. Explains that, first, numeric al instabilities in the form of spurious oscillations in pressure poll ute the solution and, second, the convergence to the steady state beco mes extremely slow owing to bad conditioning of the different speeds o f propagation. By using a stabilized method, allows the use of equal-o rder interpolations in a consistent (weighted-residual) formulation wh ich stabilizes both the convection and the continuity terms at the sam e time. On the other hand, by using specially devised preconditioning, assures a rate of convergence independent of Mach number.