Characterization of nonequilibrium shock interaction in CO2-N2 flows over double-wedges with respect to Mach number and geometry

The characterization of the shock interaction mechanism originating from the high-Mach nonequilibrium flow over double-wedge geometries is key to the design of hypersonic vehicles. The impact of changes in the freestream Mach number and double-wedge geometry on the patterns of shock interaction is investigated by means of numerical simulation in the case of CO2-N2 flows. The extended laminar Navier–Stokes equations with a two-temperature model to account for translational-to-vibrational internal energy transfer are considered the physical model of this type of flow. Simulations show that reducing the freestream Mach number leads to an increase in the separation region, both in the compression corner and in the locations of shock impingement. The impact of the size of the separation region on the patterns of interaction is such that it causes variations in the type of shock interaction. From the point of view of the flow physics near the wedges, decreasing the freestream Mach number has an equivalent effect to increasing the angle of the second wedge and an opposite effect to increasing the freestream temperature on the pattern of interaction. Results show that decreasing the freestream Mach number leads to an overall reduction in pressure and heating loads along the surface of the wedges and smaller regions of thermal equilibrium behind the bow shock.