Ground Test of Transition for HIFiRE-5b at Flight-Relevant Attitudes

A $2:1$ elliptic cone model was tested in a Mach 6 quiet wind tunnel at both low and elevated freestream noise levels. Simultaneous measurements were made using an infrared camera and pressure sensors that were mounted flush with the model surface. The model was inclined at angles of attack and yaw angles similar to those in the HIFiRE-5b flight test. As in flight, it was observed that crossflow transition was significantly more sensitive to yaw angle than angle of attack. With respect to the yaw angle, the windward side of the model was more unstable to crossflow than the lee side. Changing the yaw angle by 1 deg in quiet flow resulted in a 20% decrease in the minimum crossflow transition Reynolds number. Angle of attack had a larger effect on transition for mixed yaw and angle-of-attack orientations than for pure angle of attack. In the mixed orientations, positive yaw angles had little effect on the amplitude of traveling crossflow waves, whereas negative yaw angles resulted in a substantial suppression of traveling crossflow.