Large-eddy simulations on a dynamic separation control using spanwise type plasma actuator (SP-PA) were conducted with feedback control at a Reynolds number of 2.56 × 105. A pressure sensor was installed at the 5% chord position of the airfoil surface. In this study, we focused on the shrinkage and collapse of laminar separation bubbles and developed a control law. The variance value is calculated from the history of the pressure coefficient, and the shrinkage of the laminar separation bubble is detected in order to determine the timing for PA activation, based on the control law. Then, based on the variance value, the advection of the dynamic stall vortex generated by the collapse of the laminar separation bubble is detected, and the PA is stopped. As a result, the application of this control law was found to delay the formation of the dynamic stall vortex by approximately 4°, increase the stall angle, and reduce the activation time of the PA, compared to a predetermined control method used in the previous study.
OZONO et al. (Wed,) studied this question.