Plasma Actuation for Mitigation of Fluctuating Loads on Airfoils: An Experimental Study

Wind tunnel measurements are performed to investigate the potential for mitigation of aerodynamic load fluctuations on airfoils, as the main source of fatigue for wind turbines, using plasma actuators. The experiment consists of aerodynamic force measurements using six strain gauges and 2-component velocity measurements using particle image velocimetry (PIV). The analysis is focused on the aerodynamic loads, the mean flow, the turbulent kinetic energy and the proper orthogonal decomposition (POD) modes and their energy budget. The main findings are: (i) the actuation increased the lift coefficient for all the range of a, with an average and maximum increment of 0.05 and 0.1, per unit span of the actuator; (ii) the actuation deflects the airfoil near wake downward, resulting in the so-called virtual cambering effect; (iii) the actuation increases the TKE near the trailing edge, which could increase the airfoil trailing-edge noise; (iv) the POD analysis reveals that the actuation increases the size of the vortical structures in the near wake and the energy budget of the first POD modes, esp. at high angles of attack prior to stall.