Hypersonic Boundary Layer Transition on the STORT Ogive Geometry: Part II of Experimental Investigation

Experiments were performed to investigate hypersonic boundary layer transition on a scaled STORT ogive model in the Mach 5 Ludwieg Tube at the University of Arizona. Tests were performed at 0◦ and 1◦ angle of attack and the freestream unit Reynolds numbers ranged from 5.33 × 10⁶ /m to 23.4 × 10⁶ /m. Instrumentation and optical diagnostics included pressure sensors, infrared thermography and high speed schlieren to investigate the primary transition mechanism. PCB data indicated the presence of entropy layer and first mode instability at 0◦ and frequency of first mode instability agreed with linear stability theory calculations. Analysis with schlieren images confirmed the presence of entropy layer instability. Transition onset was observed in the IR results at Re’ = 12.4 × 106 /m and there was good agreement of the IR results with CFD. Further investigation is required to confirm the instabilities present at 1◦ but preliminary analysis suggests the presence of first mode with no evidence of crossflow instability.