Response of shock interaction patterns to different freestream conditions in carbon-dioxide flows over double-wedges

The shock interaction originating from a hypersonic laminar flow over a double-wedge can lead to different flow patterns depending on geometrical parameters such as the lengths and angles of the each wedge, as well as flow parameters such as the mixture and freestream conditions. In this work, the effect of the freestream Mach number on the patterns of shock interaction is numerically investigated for a CO ₂-N ₂ nonequilibrium flow over different double-wedge geometries. The numerical analysis is performed by solving the laminar Navier–Stokes equations within the framework of a two-temperature model to account for translational–vibrational internal energy transfer. Results show that the size of separated flow regions, both in the compression corner and locations of shock impingement, increase with decreasing Mach number. This revealed to have a significant impact on the patterns of interaction, since the size of a separation region dictates if additional shocks are generated, potentially leading to more complex mechanisms of interaction. It was concluded that decreasing the freestream Mach number has a similar impact as increasing the angle of the second wedge on the pattern of interaction. The parametric study also shows that decreasing the freestream Mach number leads to overall lower surface pressure and heating, as well as smaller regions of thermal equilibrium.