High-performance wind turbines using active flow control

A feasibility study for implementing Active Flow Control (AFC) methods to improve the performance of wind turbines was performed. The experimental effort investigated the impact of using Tel-Aviv University (TAU) Piezo-fluidic AFC actuators to control boundary layer separation from thick airfoils that are suitable for wind turbine rotor blades. It was demonstrated that the AFC actuators can replace passive vortex generators (VGs) that are used for boundary layer separation delay today, without the inherent drag penalty that the passive devices cause. It has been shown that TAU fluidic actuators are suitable for flow control in wind turbine application due to fact that they are adjustable for wider Reynolds number range, while vortex generators are tuned to perform well in one design point. It was demonstrated that AFC can effectively double the maximum lift of this airfoil at low Reynolds numbers. A possible application is a significant reduction of the turbine start-up velocity. It was also found that even for a contaminated blade, AFC is capable to delay stall and decrease drag using low energy expenditure. The effectiveness of the AFC method was examined using a newly defined aerodynamic figure of merit (AFM).