The spatial–temporal evolution of coherent structures generated by an asymmetrical dielectric barrier discharge (DBD) plasma actuator is an intriguing unsteady process with profound implications for revealing the controlling mechanism of the plasma actuator and promoting the control effect of the DBD plasma actuator at high wind speed and high Reynolds number. In this study, the induced coherent structures of the plasma actuator are studied systematically with a particle image velocimetry for a range of force coefficients ($0.24\le C_x\le 0.89$). Results indicate that the vortices that shed periodically from the downstream edge of the exposed electrode are a result of the amplification of natural disturbances in the jet shear layer. During later evolution, the adjacent vortices pair up to form a new vortex, leading to a reduction of the dominant frequency in the velocity spectra. Further downstream, the coherent vortical structures decay considerably, correlating with the shear-layer transition process in the plasma wall jet. The vortex shedding frequency is observed to scale with the force coefficient according to $f_0\sim (C_x{)}^n$, which is of importance to the selection of the dominant frequency by adjusting the actuation parameters of the plasma actuator based on the characteristic frequency of the controlled flowfield and improving the control effect of the plasma actuator. With increasing force coefficient, the propagation speed of the roll-up vortices increases linearly, whereas the streamwise vortex spacing decreases monotonically. It is of great significance that the nondimensional Strouhal number $Sr*$ based on the vortex shedding frequency, vortex propagation speed, and streamwise vortex spacing is proposed and varies slightly between 0.045 and 0.065, for all the tested cases, which lays a foundation for promoting the numerical simulation model of the plasma actuator and revealing the controlling mechanism of the flow control using the plasma actuator.

由不对称介质阻挡放电 (DBD) 等离子体致动器产生的相干结构的时空演化是一个有趣的非稳态过程，对于揭示等离子体致动器的控制机制和促进 DBD 等离子体致动器在强风下的控制效果具有深远的意义。速度和高雷诺数。在这项研究中，使用粒子图像测速仪系统地研究了等离子体致动器的诱导相干结构，适用于一系列力系数（$0.24\le C_X\le 0.89$）。结果表明，从暴露电极的下游边缘周期性脱落的涡流是射流剪切层中自然扰动放大的结果。在后来的演化过程中，相邻的涡流配对形成一个新的涡流，导致速度谱中的主频率降低。再往下游，相干涡旋结构显着衰减，这与等离子体壁射流中的剪切层转变过程相关。观察到涡旋脱落频率与力系数成比例，根据$F_0～(C_X{)}^n$,这对于根据受控流场的特征频率调整等离子体致动器的致动参数来选择主频率，提高等离子体致动器的控制效果具有重要意义。随着力系数的增加，上卷涡的传播速度线性增加，而流向涡间距单调减小。无量纲 Strouhal 数具有重要意义$秒r*$ 基于涡流脱落频率、涡流传播速度和流向涡流间距提出，在0.045和0.065之间略有变化，对于所有测试案例，为推广等离子体致动器的数值模拟模型和揭示控制机制奠定了基础使用等离子执行器的流量控制。