Mechanisms for controlling the shock wave boundary layer interaction (SWBLI) by a plasma actuator array are investigated by two experiments. Low-frequency and high-frequency actuation modes are compared. The experimental results yield valuable insights into the control mechanism of SWBLI using a surface arc plasma actuator array. The schlieren snapshots and the mean and root mean square error of the image sequence and pressure measurements are analyzed to determine the control mechanisms. The high-frame schlieren images for flow visualization indicate a significant modification of the separation shock in both experiments due to thermal injection. More importantly, because the high-frequency actuation mode operates at relatively low energy, it can provide quasi-continuous perturbations, providing stable control for separation shock weakening. The I_band/I_total ratio for low-frequency unsteadiness obtained from the pressure spectrum is reduced below 5% at 10 kHz forcing. The integrated schlieren intensity I_RMS and power spectrum indicate a dominant vortex forcing effect as an additional actuation mechanism in addition to the gas heating effect that may affect the separation shock and its interaction with the boundary layer. As the plasma actuation is activated, numerous periodic streamwise vortices and small-scale trailing vortices are produced in the high-frequency actuation mode, resulting in an enhancement of the mixture upstream of the interaction region and promoting the momentum transfer to the boundary layer. In addition, the large-scale turbulence structures characterized by low-frequency unsteadiness are subject to artificial vortex shedding by the plasma perturbation, further increasing the momentum transfer in the boundary layer. We propose a conceptual model describing the vortical activity due to actuation and the interaction between plasma actuation and the SWBLI flow. Thus, a hybrid mechanism of SWBLI control associated with vortical activity exists.

通过两个实验研究了通过等离子体致动器阵列控制冲击波边界层相互作用（SWBLI）的机制。比较了低频和高频致动模式。实验结果对使用表面电弧等离子体致动器阵列的SWBLI控制机制产生了有价值的见解。分析schlieren快照以及图像序列和压力测量的均方根误差和均方根误差，以确定控制机制。用于流动可视化的高画幅裂痕图像表明，由于热注射，在两个实验中分离震荡都发生了显着变化。更重要的是，因为高频致动模式以相对较低的能量运行，所以它可以提供准连续的扰动，从而为减小分离冲击提供了稳定的控制。这在10 kHz强迫下，从压力谱获得的低频不稳定的I _band / I_总比值降低到5％以下。积分纹影强度I _RMS功率谱和功率谱表明，除了可能影响分离冲击及其与边界层相互作用的气体加热效应以外，还有一个主要的涡流强迫效应是一种附加的致动机制。随着等离子体致动被激活，在高频致动模式下会产生大量周期性的流向旋涡和小规模的尾随旋涡，从而增强了相互作用区域上游的混合物，并促进了将动量传递到边界层。另外，以低频不稳定为特征的大规模湍流结构会受到等离子体扰动的人工涡旋脱落，从而进一步增加了边界层的动量传递。我们提出了一个概念模型，描述了由于驱动以及等离子驱动与SWBLI流之间的相互作用而引起的涡旋活动。因此，存在与旋涡活动相关的SWBLI控制的混合机制。