Numerical investigation of virtual control surfaces for lift control on NACA0015 airfoil

The plasma actuators as virtual control surfaces are assessed numerically as a means to control the lift of NACA0015 airfoil at the full angle of attack (without stall). The virtual control surface for increasing lift is realized by the pressure side (PS) plasma actuators that induce an upstream jet and the suction side (SS) plasma actuators that induce a downstream jet (SSD plasma actuator), while the one for reducing lift is realized by the SS plasma actuators that induce an upstream jet (SSU plasma actuator). Numerical simulation is achieved by solving the two-dimensional Reynolds averaged Navier-Stokes using the finite volume method. The plasma actuator adopts the empirical model proposed by the author before. The simulation of the air flow was performed for the freestream velocity of 20 m/s (Re=1.03 x 106) and the induced jet momentum coefficient between 0.0846% and 0.9027%. The calculation results show that the optimal number of DBD actuators for increasing the lift is related to the angle of attack. The SS flow separation of the high angle of attack greatly reduces the control effect of the PS actuator, which can be eliminated by arranging the actuators in front of the separation point. Finally, a virtual control surfaces configuration containing three groups of seven plasma actuators is obtained.