Heating and chemistry effects on the shock-boundary layer interaction under hypersonic flow over a double wedge

This work aims to enhance the understanding of shock-boundary layer interactions (SBLI) in hypersonic flow by exploring the roles of wall heating and chemical interactions. A double wedge geometry, with the first ramp angled at 34 degrees and the second ramp at 64 degrees, is placed in the test section of the Sandia Hypersonic Shock Tunnel (HST). The free-piston facility is used to generate high-speed flow at Mach 8 with a stagnation enthalpy of 3.8 MJ/kg. To investigate the effects of heating and air chemistry on the SBLI, resistive heating is applied to a graphite sample on the first ramp, raising its temperature to 1800 K. Nitrogen is used as the test gas to isolate the effects of heating, thereby omitting any production of oxygen in the freestream, while air is employed as the freestream gas to examine chemical interactions. Utilizing sensitive high-speed schlieren imaging and high-frequency pressure sensors, we measure the size of the shock layer and SBLI region, track the location of the triple point impingement shock on the second ramp, and obtain surface pressure measurements. Preliminary results indicate that both wall heating and chemical interactions affect the SBLI, with wall heating exerting a more pronounced influence on the gas dynamics compared to chemical interactions, suggesting that thermal effects play a critical role in the SBLI behavior.