Comparisons between Measurements in Regions of Laminar Shock Wave Boundary Layer Interaction in Hypersonic Flows with Navier-Stokes and DSMC Solutions

Experimental studies were conducted in conjunction with computations in a code validation exercise to examine the ability of DSMC and Navier-Stokes techniques to predict the complex characteristics of regions of shock/shock and shock/ boundary layer interactions in hypervelocity flows. In the experimental program, detailed heat transfer and pressure measurements in laminar regions of shock wave/boundary layer interaction, and shock/shock interaction, over hollow cylinder/flare and double cone configurations in hypersonic flow. The experimental studies were conducted for a Mach number range from 10 to 12 with Reynolds numbers from 1 x 104 to 5 x 105 and stagnation temperatures from 2,000 R to 5,000 R. Miniature high-frequency thin-film and piezoelectric instrumentation were employed to obtain the high spatial resolution required to accurately define the distribution of heat transfer and pressure in the strong gradients which occur in regions of shear layer reattachment and shock/shock interaction. The program reported here was conducted in two phases. In the first phase of the code validation study, measurements and blind computations were made over complete hollow cylinder/flare and double cone configurations in high temperature flows at Mach 10 and 12 for a range of freestream Reynolds numbers. In the second phase of the program, detailed heat transfer and pressure measurements were made over an extensive range of Reynolds number and total enthalpy conditions using only the hollow cylinder and the 25 conical segment of the models tested earlier in phase I. The selection of the freestream conditions employed in this second phase of the program was performed in conjunction with computations of the contoured nozzle flows and the flows over the two simple model configurations. Based on the results of the latter studies, we validated the computational schemes used to predict the properties of the freestream developed in the test section of the tunnel.