Prediction of Boundary Layer Transition on Hypersonic Vehicles in Large-Scale Wind Tunnels and Flight

A comprehensive framework for hypersonic boundary layer transition predictions applicable to wind tunnel and free flight conditions is proposed. The distinguishing feature of this transition prediction framework is that it is developed from the ground up allowing full integration of the important transition regions (receptivity region, linear/secondary/nonlinear stability regimes, etc.) and additional aspects that affect the transition process (e.g. free-stream turbulence and acoustic disturbances). This development does not target incremental improvements in current state-of-the-art prediction tools (e.g LST, PSE/NPSE, etc.) but it addresses the transition process as a whole in a fully integrated way. The important transition regions are coupled through a closed optimization loop that is used to determine the extent of the transition region based on available input free-stream turbulence levels and acoustic power spectra. The predictions for each regime will be validated against existing and newly generated DNS databases and experimental data. A key advantage of this approach is that it is not limited to simple geometries. The approach is applicable to complex geometries relevant for applications of our industry partner Raytheon Missile Systems (Tucson, AZ). This framework will be able to assist product development in early design cycles and bears the potential for enabling innovative designs.