Preliminary Study of the Effect of Environmental Disturbances on Hypersonic Crossflow Instability on the HIFiRE-5 Elliptic Cone
2017 by Ian Neel, Andrew Liedy, Rodney Bowersox. IR thermography was used to image and analyze suspected crossflow instabilities on a 2:1 elliptic cone in a conventional Mach 6 hypersonic wind tunnel for a unit Reynolds number range of 2.1-8.2E6/m. Two models, scaled at 38.1% of the HIFiRE-5 flight test model, were machined from PEEK plastic to facilitate this study. The surface roughness of each model was characterized using a laser profilometer. Surface heat flux maps, generated from IR thermography, on the improved elliptic cone model are qualitatively similar to heat flux results seen in other experiments but also show evidence of stationary crossflow vortices previously only observed in oil flow images. The second model, which has higher levels of periodic roughness due to machining error, displayed elevated heat flux levels and an onset of transition farther upstream for a given freestream condition. A plan for future experimentation, building on these preliminary results, is discussed.