NATIONAL INSTITUTE OF AEROSPACE ASSOCIATES

TRANSITION PHYSICS AND MODELING FOR HYPERSONIC VEHICLES. NASA LANGLEY RESEARCH CENTER HAS FORMED A HIGH-SPEED LAMINAR-TURBULENT TRANSITION (HBLT) TEAM CONSISTING OF RESEARCHERS FROM MULTIPLE ORGANIZATIONS COLLABORATING IN AN EFFECT TO TACKLE BOUNDARY-LAYER TRANSITION PROBLEMS THAT ARISE IN THE HYPERSONIC FLOW REGIME. THE STUDY OF LAMINAR-TURBULENT BOUNDARY-LAYER TRANSITION IS AN IMPORTANT ASPECT OF RESEARCH IN FLOWS OVER HYPERSONIC VEHICLES. THE ACCURATE PREDICTION OF TRANSITION LOCATIONS ON SUCH VEHICLES IS A VITAL COMPONENT OF THE DESIGN AND ANALYSIS. THE LANGLEY STABILITY AND TRANSITION ANALYSIS CODE (LASTRAC) IS A PUBLICLY RELEASED CODE (US-PERSON ONLY) FOR BOUNDARY-LAYER TRANSITION ANALYSIS, AND IS BEING USED BY MANY IN THE INDUSTRY AND ACADEMIC INSTITUTIONS. FOR HYPERSONIC FLOWS SUCH AS THOSE OVER AN ATMOSPHERIC REENTRY VEHICLE, THERE ARE CHEMICAL REACTIONS TAKING PLACE AND NON-EQUILIBRIUM EFFECTS BECOME IMPORTANT. THE OVERALL OBJECTIVE OF THIS TASK IS TO ENHANCE LASTRAC BY INCORPORATING CHEMICAL AND NON-EQUILIBRIUM CAPABILITIES, WHICH IS CURRENTLY VERY LIMITED. WITH THESE ADDITIONAL CAPABILITIES, A WIDER RANGE OF PROBLEMS IN HYPERSONIC FLOWS CAN BE SOLVED. THE WORK PROPOSED HERE IS FOR THE FURTHER DEVELOPMENT ALONG THIS LINE TO INCLUDE NONLINEAR CHEMICAL REACTION MODELS IN LASTRAC.