TRANSITION OF THE HYPERSONIC BOUNDARY LAYER ON A CONE. PART 1. EXPERIMENTS AT MACH NUMBER = 12 AND 15

The GE-SSL shock tunnel, fitted with a large contoured nozzle, was used to observe transition of the boundary layer on a 12 ft., 5 degree cone. Free stream flow Mach numbers were 12 and 15 and were essentially uniform. Surface heat transfer distributions were obtained and these allow the definition of distinct laminar, transitional, and turbulent regions. Comparison is made also with measurements of the structure and thickness growth of the boundary layer. These observations were made with controlled variations in the wall temperature ratio, nose bluntness and unit Reynolds number. A discussion is presented of the influence of these parameters on transition and comparison made with recent results in other facilities.