Prediction of Hypersonic Boundary-Layer Transition in Wind Tunnels and Flight

Boundary-layer transition is important in the design of hypersonic vehicles since it significantly affects the aerodynamic drag and heating.The ultimate goal of this SBIR project is to assemble an easy-to-use, accurate, efficient and robust suite of codes to predict boundary-layer transition on hypersonic vehicles in large-scale wind tunnels and flight.The Phase I objectives are to develop algorithms to predict the onset of 2nd mode dominated boundary-layer transition in large-scale wind tunnels and include relevant physics to allow extrapolation to flight. The EPIC stability code solving the nonlinear parabolized stability equations (NPSE) will be coupled to mean flow solutions and receptivity models relating tunnel noise to initial 2nd mode amplitudes and frequencies for the initial conditions for EPIC NPSE marching.The 2nd mode saturation amplitudes will be computed by EPIC or a breakdown amplitude correlation will be applied in Macks amplitude method.The algorithms will include the use of Direct Numerical Simulations (DNS) to provide physics-based receptivity models applicable to both wind tunnels and flight. In Phase II the algorithm will be implemented and validated.Crossflow instability and transient growth will be computed and the length of the transition region will be predicted.