Evolution of disturbances generated by a heat source in a supersonic boundary layer during shock wave interaction

Direct numerical simulations of propagation of disturbances generated by a heat source in a supersonic boundary layer interacting with an oblique shock wave are performed by the HyCFS-R hybrid code. The processes of excitation and evolution of unstable disturbances in the boundary layer, the influence of the incident shock wave on evolution of disturbances, and also the effect of disturbances on boundary layer separation and flow development in the separation region and in the laminar-turbulent transition region are studied. The influence of the duration of the thermal pulse on excitation and development of unstable waves in the boundary layer and interaction region is investigated. A case of disturbance generation by a pair of sources located at a certain distance from each other is considered. It is shown that reduction of the heat pulse duration leads to enhancement of the amplitudes of the first and second harmonics of the main unstable mode. For this reason, the disturbance spectrum in the interaction region changes, and flow turbulization is accelerated, which leads to reduction of the separation region size.