HIFiRE-5b Flow Computations and Attitude Determination via Comparison with Flight Data

Laminar and turbulent flow computations are carried out for a range of conditions bounding the flight conditions of the Hypersonic International Flight Research and Experimentation (HIFiRE) 5b laminar-turbulent transition research flight. The resulting computational database is used to create an interpolant for heat transfer and pressure in the following variables: angle of attack, yaw angle, Mach number, Reynolds number, circumferential station, and streamwise station. Flight pressure is compared to angle-of-attack- and yaw-dependent computational results for pressure distribution at selected time points in the descent trajectory of the HIFiRE-5b flight. Computed pressures, normalized by freestream pressure, are interpolated to the flight Mach numbers at each time point throughout the descent trajectory; and the angle of attack and yaw are estimated from measured pressure by determining the combination minimizing the difference between the measured and computed pressures. The resulting vehicle attitude is compared to the vehicle attitude derived from inertial measurement unit and Global Positioning System results from the flight. The two methods showed excellent agreement for the entirety of the analyzed reentry portion of the trajectory.