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

For a vehicle in hypersonic flight, the natural transition of a boundary layer from laminar to turbulent flow depends on multiple factors including the free-stream conditions, the noise level and frequency spectrum of free-stream disturbances, the geometry of the vehicle and the vehicle surface properties.To predict boundary layer transition for flow over a given vehicle, one or more of these factors need to be investigated.In this SBIR Phase I effort, our team will develop computational tools and methodologies for the prediction of boundary-layer transition in experimental facilities and methods for extrapolation of predictions to flight conditions.Our team proposes a framework using a hierarchy of analysis methods including linear stability theory, parabolized stability equations, and global stability analysis, anchored by the results of direct numerical simulation and experimental data, to analyze hypersonic boundary layer stability to determine whether transition for a given vehicle of interest is likely due to one or more possible mechanisms.When appropriate, analysis methods will use physical models relevant to high-enthalpy, chemically-reacting flows.The resulting methods will fit into into a framework which will assist a researcher, designer, or engineer with method selection and execution, results visualization, and data interpretation.