Geometry and Test-Time Effects on Hypervelocity Shock-Boundary Layer Interaction

Experiments are carried out to address potential sources of discrepancies between experiments and simulations of shock-boundary layer interactions in hypervelocity flow: spanwise effects on shock interactions and flow separation, as well as flow field evolution and potential unsteadiness. A double-wedge and double-cone geometry are studied in two hypersonic impulse facilities, the HET and T5. The test conditions in the two facilities are selected to have the same nominal stagnation enthalpy but different unit Reynolds number. For the double-wedge model, the extent of the finite edge effects on shock structure and heat flux is assessed using chemiluminescence and surface measurements respectively. Heat flux in the separated region shows no variation within a nondimensional span of 0.05 away from the centerline. Over the respective test times of 250 µs in HET and 1 ms in T5, the normalized heat flux data obtained in the two facilities over the same model are in very good agreement. The invisicid establishment period for the double-cone is in agreement between the two facilities.