Impacts of periodic disturbances on shock wave/turbulent boundary layer interaction

Shock wave/turbulent boundary layer interaction (SBLI) on flat plate is investigated with different added periodic disturbances via large eddy simulation. Turbulence analysis of boundary layer and SBLI flow field are compared among different cases. It is found that disturbances have little impact on characteristics of the viscous layer. The amplifications of turbulent kinetic energy on logarithmic layer and outer layer are further strengthened with shock wave/turbulent boundary layer interaction. Distributions of skin frictions reveal that the separation bubble shrinks under effect of disturbances. Despite the obvious reduction of the separation bubble by disturbances, the streamwise scale in instantaneous slices does not follow the same pattern, owing to the phase discrepancy of different frequencies. The flow field of shock wave/turbulent boundary layer interaction is spatially and temporally influenced by the propagation of disturbances. As a result, the oscillation of the separation bubble and separation shock is reinforced. Conclusion is verified through the analysis of power spectral density that disturbances do not affect the viscous layer despite the frequency. However, disturbances make substantial difference to low-frequency signals, corresponding to the large-scale motion in the outer layer.

Automated summary

The study reveals that disturbances have little impact on the characteristics of the viscous layer, but they do strengthen the amplification of turbulent kinetic energy in the logarithmic layer and outer layer. While disturbances significantly reduce the separation bubble, they do not consistently affect the streamwise scale in instantaneous slices.