Mechanisms of hypersonic shock wave and turbulent boundary layer interaction on a cone/flare

A direct numerical simulation of a hypersonic 7°–34° cone/flare model at the Mach number Ma∞ = 6 and unit Reynolds number Re∞ = 10 800/mm is performed to investigate the shock wave/turbulent boundary layer interaction of three-dimensional configuration. To study the influence of spanwise curvature, the differences between the cone/flare configuration and the double wedge configuration are discussed. Compared to the double wedge, the height of the separation bubble of the cone/flare is lower, and the skin friction coefficient and Stanton number in both the upstream undisturbed region and the downstream reattachment region are smaller. The Görtler vortex analysis shows that the cone/flare configuration produces more Görtler vortices, but with lower intensity. The turbulent kinetic energy budget is analyzed, and the results indicate that the distribution of turbulent kinetic energy in the interaction region differs significantly from that in the upstream undisturbed region, the peak values of each term increase notably, with the influence of the turbulent transport term being significantly enhanced and the influence of the viscous dissipation term notably weakened. The spectral proper orthogonal decomposition analysis reveals that in the streamwise/wall-normal plane, the low-frequency characteristics of the flow are associated with the separation bubble and the shear layer in the reattachment region, while the high-frequency characteristics are primarily linked to turbulent fluctuations. In the streamwise/spanwise plane, the low-frequency characteristics are associated with the upstream velocity streaky structures and the large-scale alternating positive and negative streaky structures that form along the spanwise direction after the flow reattaches.