A study of arc plasma energy deposition flow control on blunt-headed protuberance induced STBLI

This paper presents experimental results of flow control method using plasma energy deposition on shock wave interactions induced by blunt-headed protuberance on a flat plate at Mach 2.0. Upstream of the leading edge of the protuberance, plasma energy deposition was generated by high-frequency pulsed discharge at three streamwise locations on the flat plate. High-speed Schlieren technique was utilized to investigate the unsteadiness characteristics of shock wave/turbulent boundary layer interaction (STBLI). The visualization results reveal that thermal bubble structures formed by the pulsed discharge could attenuate the separation shock continuously, resulting in a 12.8% decrease in the maximum pressure in the interaction wall. Experimental findings disclosed the dependency of this mitigation efficacy on the average discharge power. The pulsation of the separation shock was also affected by average discharge power, while the pulsation of boundary layer and shear layer was linked to both the discharge power and frequency. The numerical results predicted flow topology under control well with experiment results, low-density plasma layer was formed by high-frequency discharge, which weakening the separation shock substantially, the "lambda" shock intensity was also decreased. The flow field of numerical simulation and experiments are in good agreement. Additionally, the control of the thermal bubble structures on STBLI was very effective in terms of reducing the motion and weakening the intensity of the lowfrequency separation shock, and augmenting the high frequency component in the turbulent boundary layer and shear layer.