Unsteady Aerodynamic Load Control Using DBD Plasma Actuators

Abstract

Big wind farms with big wind turbines are more cost effective and produce greener electricity compared to smaller ones. This is one of the reasons for the growth of wind turbine size during the last 3 decades. However, as wind turbines become bigger, their blades become longer, thicker and heavier. This results in larger unsteady loads on blades which is an important limitation for their life time and their size growth. Flow control has emerged as the promising solution both for improving the aerodynamic efficiency and controlling the unsteady loads on wind turbine blades. DBD plasma actuator is an active flow control mechanism that has shown high potentials for unsteady load control with the capability to change lift coefficient to a significant amount with a very fast response time. The current research first intends to identify the variations of angle of attack and lift coefficient on wind turbine blades as a result of gravitational loads, mass and aerodynamic imbalances, turbulence, wind shear, yawed inflow and tower shadow and investigate their corresponding frequencies and the fatigue damage from the blade root bending moments. Then, (single and multi) DBD plasma actuator with different configurations will be used on three different trailing-edge shapes (round, half-round and sharp) of modified version of ’NACA64-2-A015’ airfoil to control the aerodynamic loads via circulation control. This is managed either by manipulation of Kutta condition or acting as a virtual Gurney flap. Furthermore, it is intended to investigate the correlation between the frequency of actuation, frequency of vortex shedding and the amount of lift enhancement.