Flowfield-Dependent Mixed Explicit-Implicit(FDMEI) Algorithm Toward Direct Numerical Simulation in High Speed Flows

Abstract

Abstract : This report covers the results of the research on new concepts and formulations aimed toward direct numerical simulation(DNS) dealing with high. speed flows. The research was motivated by the fact that it is desirable to develop a CFD program which can be applied to all speed regimes, both compressible and incompressible, both viscous and inviscid, and both laminar and turbulent flows, ideal for shock wave turbulent boundary layer interactions in hypersonics. The popular notion that DNS will resolve all turbulent microscales can be applied to incompressible flows. For compressible flows with shock waves interacting with turbulent boundary layers, however, difficulties arise in dealing with complex physical phenomena such as transition from laminar to turbulent flows, relaminalization, interactions between viscous and inviscid flows, and high temperature gradients close to the wall, particularly in hypersonics. No currently available CFD techniques are capable of resolving these physical phenomena simultaneously even in DNS.