In this study, the effect of the burst ratio (BR) on flow separation control using an alternating-current dielectric barrier discharge plasma actuator (DBDPA) was investigated. The effects of BR on the lift force on the NACA0015 airfoil were quantitatively evaluated by force measurements, and those on the flow field were measured by particle image velocimetry (PIV) and Schlieren visualisation. The force measurements showed that the recovery of the lift force decreased as BR increased, indicating that the flow separation control effect of the DBDPA decreased as BR increased. The PIV measurements showed that the temporal variation in vorticity was smaller at BR = 80% than at BR = 20% and that the vorticity did not change periodically at BR = 100%. Schlieren visualisation showed that DBDPA-induced flow produced a density gradient near the DBDPA electrode; the gradient was periodically observed and was found to be proportional to BR. In contrast, the density gradient in the separated shear layer varied at the end of each burst waveform, and the degree of variation decreased as BR increased. In addition, the root mean square value of the Schlieren signal intensity in the separated shear layer decreased with increasing BR. This result suggests that not only the strength and frequency of the disturbance input of the DBDPA but also the switching timing of the disturbance input are important for producing vorticity and thereby ensuring flow control.

在这项研究中，使用交流电介质阻挡放电等离子体致动器 (DBDPA) 研究了爆裂比 (BR) 对流动分离控制的影响。BR 对 NACA0015 机翼升力的影响通过力测量进行定量评估，对流场的影响通过粒子图像测速 (PIV) 和纹影可视化进行测量。力测量表明，升力的恢复随着 BR 的增加而降低，表明 DBDPA 的流动分离控制效果随着 BR 的增加而降低。PIV 测量表明，BR = 80% 时涡度的时间变化比 BR = 20% 时小，并且涡度在 BR = 100% 时没有周期性变化。纹影可视化显示 DBDPA 诱导的流动在 DBDPA 电极附近产生了密度梯度；梯度被定期观察并被发现与 BR 成正比。相比之下，分离的剪切层中的密度梯度在每个脉冲波形结束时都发生了变化，并且随着 BR 的增加，变化程度减小。此外，分离的剪切层中纹影信号强度的均方根值随着BR的增加而减小。该结果表明，不仅 DBDPA 扰动输入的强度和频率，而且扰动输入的切换时间对于产生涡量并从而确保流量控制都很重要。分离的剪切层中的密度梯度在每个脉冲波形结束时发生变化，变化程度随着BR的增加而减小。此外，分离的剪切层中纹影信号强度的均方根值随着BR的增加而减小。该结果表明，不仅 DBDPA 扰动输入的强度和频率，而且扰动输入的切换时间对于产生涡量并从而确保流量控制都很重要。分离的剪切层中的密度梯度在每个爆发波形结束时发生变化，变化程度随着BR的增加而减小。此外，分离的剪切层中纹影信号强度的均方根值随着BR的增加而减小。该结果表明，不仅 DBDPA 扰动输入的强度和频率，而且扰动输入的切换时间对于产生涡量并从而确保流量控制都很重要。