An investigation was conducted in a hypersonic shock tunnel to deter-mine the induced pressures and the local heat transfer rates for a flat plate with sharp leading edge. The free stream Mach number range was 7.95 to 25.1 with stagnation temperatures of approximately 2300° and 7000°R. For these temperatures and Mach number conditions, the strong interaction parameter, varied from 2.35 to 826 and the corresponding Knudsen numbers, based on the ratio of the free stream mean free path and the leading edge thickness, varied from 0. 4 to 86. For free stream Mach numbers greater than 10. Knudsen numbers of approximately unity, and perfect gas conditions, the observed experimental induced pressures varied and the local heat transfer rates varied as predicted by the no insulated flat plate theory of Li and Hamamatsu. the leading edge slip phenomenon drastically reduced both the induced pressures and local heat transfer rates as compared to the theoretical values predicted with no slip at the surface. Schifrin photographs indicate the presence of slip flow at the sharp leading edge in that the formation of the strong shock wave and the boundary layer was delayed Both the Knudsen number and the free stream Mach numbers are important physical parameters that determine the extent of the exlent of the slip-flow region.nManuscript received March 12, 1963.
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