Proportional Aerodynamic Performance Modulation using an Active Gurney Flap on a Wind Turbine Blade Section

Flow control devices can provide promising improvements in wind turbine blade performance by actively modulating the aerodynamic performance of the blade, so that the system can better adapt to varying flow conditions, achieve higher overall efficiency and be more robust to off-design operation. We present wind tunnel measurements using an Active Gurney Flap (AGF) located near the trailing edge of the wind turbine blade on the pressure surface that can be raised and lowered as needed, thus enabling flow control with additional lift, but avoiding the drag penalty when that lift boost is not required. Real-time adjustment of the active gurney flap (AGF) could be used to adaptively modulate the aerodynamic performance according to flow conditions. Lift, drag and pitching moment measurements are reported over a range of Reynolds number from 160,000 to 414,000, angle of attack from -10 to 15 degree and AGF deployment positions from 0 to 135 degrees. We show that the AGF provides proportional control to the aerodynamic performance, and improves the lift and pitch moment performance with an increased lift to drag ratio. The dynamic response of the force coefficients as the AGF is deployed is also discussed.