Planar Investigation of CobraMRV Flowfields Using Pulse-Burst, Cross-Correlation Doppler Global Velocimetry

Le résumé fourni par la source

Flowfields around a model reentry vehicle, a scaled version of a CobraMRV, are investigated with a combination of high-speed planar laser Mie scattering and planar pulse-burst, cross-correlation, Doppler global velocimetry for scalar visualization and streamwise velocity measurements, respectively. Tests were conducted in the NASA Langley 4-Foot Supersonic Unitary Plan Wind Tunnel over a range of different tunnel operating conditions and model configurations and focused on the shock/boundary-layer interaction under the model. Pseudotomographic reconstructions of these flowfields were assessed for mean flow structure. Mach- and Reynolds-number-dependent effects were examined, including changes in bow-shock angle and standoff distance with Mach number along with global changes to the interaction topology with Reynolds number. Measurement uncertainties ranged from 50 to [Formula: see text] throughout the region of interest, driven largely by angular uncertainties. The mean measurement accuracy assessed in the tunnel freestream was 5.2% of tunnel-predicted values, while larger deviations were found in the immediate postshock regions due to assumptions made to assess velocity. Minor velocity and structural differences were also observed between repeated test cases. A series of recommendations to improve the fidelity of the velocimetry for future experiments by roughly a factor of 4 is given.

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