A full-scale model of the BOLT-1B flight experiment geometry was tested in The University of Queensland’s X3/R Stalker Tube. Existing and new flow conditions for X3/R using the Mach 7b nozzle were used and developed to provide flight-equivalent flows at 10 points on the trajectory of the BOLT-1B flight at altitudes between 23 and 33 km. The freestream unit Reynolds numbers ranged between 1.81 and Formula: see text. Steady flow test times, after flow establishment, varied from 2.3 to 4.8 ms. Heat flux and surface static pressure measurements were made at locations matching those on the flight vehicle on the primary experimental surface. Laminar, transitional, and turbulent boundary layers were observed evolving as the freestream Reynolds number increased. The shape of the transition front across the model was similar to that in flight, but transition Reynolds numbers were much lower in the tunnel. This is attributed to higher freestream turbulence levels in the shock tunnel than in flight.
Trudgian et al. (Sat,) studied this question.