Study of ramp-induced hypersonic shock-wave/boundary layer interaction controlled with steady jet

In this paper, the steady jet is applied upstream of a 30° compression ramp in a turbulent boundary layer with a Mach number of 5.0 and a momentum-thickness Reynolds number of 5000. Direct numerical simulations are conducted to investigate the impact of the jet on the shock wave/boundary layer interaction and the feasibility to mitigate the flow separation and reduce the wall heat flux peak. The jet is capable of generating large-scale streamwise vortex and contributes to a spanwise heterogeneity of turbulent structures and mean quantities. It is found that the jet can effectively reduce the Mach number upstream of the interaction region and lead to the downstream motion and reduced strength of the separation shock. Compared with the baseline case, the spanwise-averaged separation area and length are reduced by 46% and 31%. Under the combined contribution of the jet and the Görtler-instability, the intensity of the mean large-scale streamwise vortex on the compression ramp is much stronger than that upstream of the interaction region and that of the baseline case. This consequently leads to a large spanwise variation of the mean wall skin friction and heat flux with their maximum values obtained around the spanwise portion where the downwelling occurs. The jet works to reduce the peak value of the mean spanwise-averaged wall heat flux up to 12%, owing to the reduced intensity of the mean-convection and turbulent mixing. Compared with the baseline case, the peak value of the spanwise-averaged turbulence kinetic energy in the interaction region for the jet case is decreased, and the wall-normal location of the peak has an apparent upward motion, caused by the upwash and the resultant upward movement of the detached shear layer.