Proportional Control of Aerodynamic Forces using an Active Gurney Flap
on a Wind Turbine Section
Abstract
Real-time, proportional deployment of an Active Gurney Flap (AGF)
located near the trailing edge of the wind turbine blade on the pressure
surface is used to modulate aerodynamic performance. Wind tunnel
experiments are conducted using an AGF model based on the geometry of a
commonly used wind turbine blade over a range of Re numbers from
160 ,000 to 414 ,000, angle of attack (AOA) from - 1 0 ◦
to 1 5 ◦ , and AGF deployment positions from 0 ◦ to 1 3 5 ◦ . The torque
required to raise and lower the AGF was measured and found to be
approximately C T = 0 . 1 , independent of the deployment rate and the
Re number. Aerodynamic force measurements demonstrate that the
deployment of the AGF is capable of improving the lift and pitch moment
performance with an increased lift-to-drag ratio. Aerodynamic changes
are proportional to the AGF deployment angle, with a maximum effect
observed at 7 0 ◦ to the chord. The aerodynamic changes occur instantly
as the flap is deployed, although sudden changes in aerodynamic loading
induce mechanical vibration of the wind tunnel model on the supporting
sting.