Initial Results from the BOLT Flight Experiment

Wheaton, Bradley M.; Butler, Cameron; McKiernan, Gregory; Berridge, Dennis C.

doi:10.2514/6.2022-0345

Cited by 7 publications

References 12 publications

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Measurements of Natural Turbulence During the BOLT II Flight Experiment

Wirth,

Bowersox,

Dufrene

et al. 2024

Journal of Spacecraft and Rockets

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A Mach 6.0 flight experiment was performed to characterize the turbulent skin friction and heat flux associated with natural transition for vehicle-length Reynolds numbers up to 45 million. This boundary-layer turbulence flight, termed BOLT II, was the second in a series coordinated by the Air Force Office of Scientific Research. Surface heat flux, skin friction, and pressure fluctuation spectra were acquired to characterize the transition process. The test geometry used concave curvature and swept leading edges to introduce a boundary layer with stationary laminar vortex streaks, competing transition mechanisms, and complex early turbulence. The analyses also showed that the spatial evolution of turbulence varied with respect to the location of the vortex heating streaks. Prominent overshoots were observed in the early turbulence within the streak. Turbulence data was collected for Reynolds numbers [Formula: see text] up to [Formula: see text]. A common [Formula: see text] was identified as the start of equilibrium turbulence for the data presented. Conjugate heat transfer simulations, both laminar and turbulent, agreed well with the experimental data, including the laminar leading edge. The Reynolds analogy ratios based on the curve fits to the data, including compressibility, were generally between 0.9 and 1.0. The observed variations were likely the result of the spatial separation of the sensors and different definitions of Stanton number normalization between flight and theory.

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Measurements of Natural Turbulence During the BOLT II Flight Experiment

Wirth,

Bowersox,

Dufrene

et al. 2024

Journal of Spacecraft and Rockets

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Development of the BOLT-2 Roughness Experiment for Flight

Berry,

Semper,

Riha

et al. 2024

Journal of Spacecraft and Rockets

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A sounding rocket research flight called BOLT-2, which stands for Boundary Layer Turbulence 2, was initiated with the goal of studying hypersonic boundary-layer transition and turbulence. The BOLT-2 research vehicle is based on a three-dimensional geometry with concave surfaces and swept leading edges that provides two separate and distinct, also redundant, flowpaths for conducting measurements. One side of BOLT-2 is dedicated to smooth surface transition and turbulence, to better study the natural instability processes, whereas the other has been assigned to study forced transition and turbulence using discrete roughness trips. The present paper is intended to document the primary drivers and decisions made that lead up to finalizing the roughness-side experiment for the BOLT-2 flight.

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Recent BOLT Discrete-Roughness Trip Results from the 20-Inch Mach 6 Tunnel

Berry

Scott

2023

AIAA SCITECH 2023 Forum

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Initial Results from the BOLT Flight Experiment

Cited by 7 publications

References 12 publications

Measurements of Natural Turbulence During the BOLT II Flight Experiment

Measurements of Natural Turbulence During the BOLT II Flight Experiment

Development of the BOLT-2 Roughness Experiment for Flight

Recent BOLT Discrete-Roughness Trip Results from the 20-Inch Mach 6 Tunnel

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