Experimental investigation of hypersonic boundary-layer transition on a cone model in the High Enthalpy Shock Tunnel (HEG) at Mach 7.5

Abstract

Hypersonic boundary-layer transition on a 7 half-angle cone was investigated experimentally in the DLR High Enthalpy Shock Tunnel G�ottingen (HEG) at Mach 7.5. The cone model, provided by the Japan Aerospace Exploration Agency (JAXA), has a length of 1100mm and was tested with nose radii of 2:25mm and 5mm. The free stream unit Reynolds number was varied over the range of 1:2 106=m to 6:2 106=m at a stagnation enthalpy of H0 = 3:3MJ=kg. The model was equipped with co-axial thermocouples to determine the transition location by means of the surface heat-ux distribution. Ten ush mountedpiezoelectric fast-response pressure transducers were used to measure the pressure uctuations in the boundary-layer associated with second mode instabilities. The results are compared to stability calculations conducted with the DLR NOn-LOcal Transition analysis code, NOLOT.