Gust alleviation using rapidly deployed trailing-edge flaps

This paper presents the results of a numerical and experimental investigation into the use of a small, rapidly actuated, actively controlled trailing-edge flap (4% chord) to alleviate the unsteady loading experienced by wind turbine blades due to atmospheric turbulence and the atmospheric boundary layer.The computational investigation demonstrated that the rejection of realistic flow disturbances should be feasible with the use of load measurements on the blade and the feedback control of a small flap. The experimental prototype subsequently successfully rejected intentionally introduced flow disturbances from the vortex street of a square block located upstream of a sting-mounted, strain-gauged wing fitted with flap. This application of control provided a very significant reduction in the unsteady loading experienced (∼81% of CLRMS).The findings show the potential of this method of load control for the rejection of unsteady aerodynamic loading by the sole use of load measurements from the wing for simple feedback control (PID/LQG).