A High-Order Cut-Cell Method for Numerical Simulation of Hypersonic-Boundary Transition with Arbitrary Surface Roughness

Hypersonic boundary-layer transition can be affected significantly by surface roughness. Many important mechanisms which involve transition induced by arbitrary roughness are not well understood. In this paper, we propose a new high-order cut cell method which combined the non-uniform finite difference method for discrete points near the curvilinear boundary and shock-fitting method for the bow shock. The receptivity process induced by interaction of Mach 5.92 flow over flat plate under the combination effect of twodimensional surface roughness and blow-suction is investigated. Both steady state solutions and unsteady solutions have been obtained by using the new method. For steady flow with roughness, there is significant change inside the boundary layer with flow separation before and after the roughness element. For unsteady flow, the results for flow instability induced by both blow-suction slot and roughness are obtained and analyzed by Linear Stability Theory (LST). These results show that the roughness element with height to be half the boundary layer thickness may delay the hypersonic transition.