Adaptive Flow Control for Optimized Wind Turbine Power Generation

Achieving greater aerodynamic efficiency from existing wind turbine designs increasingly depends on smart flow-control strategies rather than purely geometric optimization. This study introduces and evaluates a novel active lift-augmentation concept, the Active Fluid Gurney Flap (AFGF), which employs a controlled jet ejected through a narrow slot near the trailing edge on the pressure side of the airfoil. By locally modifying the pressure distribution and effective camber, the AFGF enhances lift generation without imposing the drag penalties associated with conventional fixed devices such as mechanical Gurney Flaps. The aerodynamic response of the NREL S809 airfoil equipped with the AFGF is examined through two-dimensional Computational Fluid Dynamics (CFD) simulations performed in ANSYS~Fluent. The analysis spans Reynolds numbers between Reynolds 600000 and Reynolds 1600000, and injection total pressure ratios from 1.005 up to 1.03. The Transition SST turbulence model within a Reynolds-Averaged Navier–Stokes framework is employed to accurately capture transitional and jet–boundary-layer interaction effects. Comparisons are conducted against a clean baseline and a conventional passive Gurney Flap configuration. Results demonstrate that the AFGF effectively boosts circulation and lift through controlled flow turning and surface pressure redistribution, emulating the aerodynamic performance of a mechanical Gurney Flap while avoiding its passive drag cost. Importantly, the system can be deactivated without aerodynamic penalty, preserving baseline performance. The findings reveal that the optimal injection pressure depends on the operating Reynolds number and tip-speed ratio, enabling adaptive control for varying inflow conditions. Overall, the AFGF shows strong potential as a dynamically tunable lift-enhancement system capable of improving wind-turbine power generation efficiency across a wide operational envelope.