Transition Measurements on Slender and Blunt Bodies in Ludwieg Tubes at Mach 6

Abstract

In the present study, transition measurements are conducted on slender and blunt bodies in two different facilities. A 7° half-angle cone is used as a slender body and an Apollo shaped capsule as a blunt body. The measurements are performed in the HLB of the TU Braunschweig in Germany and in the HHK-6 of the US Air Force Academy. Pressure sensors are applied to investigate transition mechanisms, while infrared thermography and coaxial thermocouples are used to detect transition location. A recent thorough investigation of the free stream disturbance is used as a basis to understand the effect of noise level on the transition location and dominating mechanism. Although both facilities are almost identical transition tends to occur earlier in the HHK-6. The maximum amplitude of the measured second mode instability was higher in the HLB. Laminar-turbulent boundary layer transition on blunt bodies was influenced as well, but to a lesser extent.