Simulations of High-Speed Flow Over an Isolated Roughness

Abstract

A study has been performed to determine the feasibility of using computational fluid dynamics as a tool for predicting hypersonic boundary layer transition to turbulence and the resulting increase in heat transfer. Of particular interest is whether Detached Eddy Simulation can be used to overcome the scaling problems associated with Direct Numerical Simulation and Large Eddy Simulation of boundary layers. Fine-grid results for a boundary layer trip oriented 45 degrees to the flow inside a Mach 10 hypersonic wind tunnel show that Detached Eddy Simulation can predict transition in this perfect-gas flow. I. Introduction Prediction and control of boundary layer transition in hypersonic flows are of crucial importance for the design of planetary atmospheric entry vehicles as well as two-stage-to-orbit reusable launch systems. Since turbulent heat transfer rates can be up to five times higher than laminar heating rates, reductions in the weight of thermal protection systems can be realized with an improved understanding of the physics of transition from laminar to turbulent flow. The gap-filler incident during Space Shuttle mission STS-114 in 2005 was a potent reminder of the importance of accurate prediction of roughness-induced boundary layer transition and the subsequent increase in surface heating 1