Flow Control of Trailing-edge Flap for Wind Turbine Blades under Deep
Dynamic Stall
Abstract
Wind turbines operating in unsteady and complex environments often
encounter asymmetric and unsteady vortex flows on the leeward side of
the blades, leading to airflow separation and dynamic stall. These
issues significantly impact the aerodynamic performance and energy
efficiency of wind turbines. However, there is a lack of research
regarding the regulatory relationship between airfoil parameters,
trailing-edge flap oscillation angles, and aerodynamic parameters. To
address this research gap, this study employs a multi-block overlapping
grid technique and a custom-programmed method to simulate active flow
control on wind turbine blades by coordinating the motion of the main
wing and trailing-edge flap during pitching oscillations. Aerodynamic
parameters of airfoils were computed to investigate the impact of
trailing-edge flap deflection direction, deflection amplitude, and other
parameters on the wind turbine blade thrust, torque, and aerodynamic
characteristics under deep stall conditions. An optimized aerodynamic
performance curve of the blade was produced. The results show that when
a deep stall occurred and the wind speed was low, the lift coefficient
of the airfoil can be increased by approximately 23% with the amplitude
αamp1=40° and the same deflection direction;
moreover, the tangential force and torque value on the blade
concurrently increased. Adjusting the motion of the main wing and
trailing-edge flap reduced the thrust and load fluctuation of the blade
by changing the flap amplitude value. Additionally, the operation
efficiency of the wind turbine improved. These results can provide a
reference for the active flow control and application of wind turbine
flaps.