Wind-tunnel experiments were performed to quantify boundary-layer instabilities both on and off the surface of a 33% scale model of the U.S. Air Force Research Laboratory/U.S. Air Force Office of Scientific Research Boundary Layer Transition (BOLT) flight geometry. Measurements were obtained in the Mach 6 Quiet Tunnel and Actively Controlled Expansion (ACE) tunnel located at the Texas A&M University National Aerothermochemistry and Hypersonics Laboratory. Surface heating was quantified using infrared thermography. Under quiet conditions, heat flux was characterized by a streak structure with no transition observed. Transition was observed within the conventional noise ACE facility in two regions: 1) in the vicinity of a mixed-mode structure and 2) in an outboard traveling crossflow region. The flow structure within a coherent vortex rollup located off centerline was further characterized under quiet flow conditions with constant-temperature hot-wire anemometry and high-frequency surface-pressure spectra. The measured mean and disturbance flow structure were in qualitative agreement with the simulations. The hot-wire spectral content showed growth in the 25–40 kHz range, which also agreed with the simulations. Surface-pressure spectral results showed similar growth in the 25–50 kHz range observed under both quiet and conventional freestream conditions.
Preflight Ground Test Analyses of the Boundary Layer Transition (BOLT) Flight Geometry
Journal of Spacecraft and Rockets ; 58 , 1 ; 67-77
2021-01-01
Article (Journal)
Electronic Resource
English