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 iin the DLR High Enthalpy Shock Tunnel Gottingen (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*10^6 /m to 6.2*10^6 /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-flux distribution. Ten flush mounted piezoelectric fast-response pressure transducers were used to measure the pressure fluctuations 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.