Closing Developments in Aerodynamic Simulation with Disjoint Patched Meshes

摘要

The research is aimed at providing computational tools and procedures as the building blocks to permit efficient solution and high resolution capture of flow structure in gasdynamic problems of realistically complex geometries. It has yielded a comparatively simple algebraic procedure for constructing two and three dimensional geometry fitted base level composite meshes in quadrilateral patches. The method provides complete control of coordinate distribution and gradient on all patch boundaries which may include slow discontinuities. A robust upwind implicit method (CSCM) was the basis to solve the multidimensional pseudo time dependent Euler or compressible Navier-Stokes equations. Research into solution algorithms for that upwind method has yielded a more robust diagonally dominant (DDADI) approximate factorization that subsequently led to a family of rapidly convergent and data storage and management efficient relaxation schemes in two and three space dimensions. Results of tests with reflecting shock capture on overset adaptively refined mesh patches in a 2-D supersonic inlet problem show for comparable accuracy a savings of about an order of magnitude in mesh points relative to uniform mesh refinement. The 3 D symmetric Gauss Seidel implicit method of planes space marching relaxation algorithm has been implemented on a system of composite patched meshes and applied in the solution of a multi rocket engine shrouded exhaust problem that features large pockets of separated base flow.