Experimental study on hypersonic inlet flow separation controlled by plasma actuators

In the field of hypersonic flight, the performance of air inlets has long been a subject of significant interest. However, controlling flow separation induced by shock wave/boundary layer interactions in hypersonic inlets remains challenging. In this study, we propose a plasma array actuation approach to control flow separation in a hypersonic inlet, aiming to further enhance its performance. For a two-dimensional compression hypersonic inlet configuration, high-speed schlieren imaging and fluorescent oil-flow visualization were employed to capture the shock wave structures and topological features of the separation region from both spatial and wall-flow perspectives. Experimental results demonstrate that high-frequency plasma actuation effectively mitigates wall flow separation, reducing the separated wall area by approximately 35.04% compared to the baseline flow. Furthermore, building on established knowledge of plasma flow control, this work systematically analyzes the distinctions between traditional plasma control methods and the specific requirements of hypersonic inlet applications. Based on this comparative analysis, a targeted control strategy is formulated. Ultimately, the mechanism by which plasma actuation controls flow separation in hypersonic inlets was investigated. This study provides adequate technical and methodological support for the application of flow separation controlled by plasma in hypersonic inlets.