Aerodynamic Effect of Winglet on NREL Phase VI Wind Turbine Blade

The primary goal in designing wind turbine blades is to maximize aerodynamic efficiency. One promising approach to achieve this is by modifying the blade geometry, with winglets to the tip. Winglets are intended to reduce the strength of the tip vortices, thereby reducing induced drag, increasing torque, and, ultimately, improving the power output of the wind turbines. In this study, computational fluid dynamics (CFD) simulations were utilized to assess the aerodynamic performance of wind turbine blades with and without winglets at various wind speeds (5, 7, 10, 13, 15, 20, and 25 m/s). The results indicate that winglets have a limited effect at low (5 and 7 m/s) and high (20 and 25 m/s) wind speeds due to fully attached and separated flows over the blade surface. However, within the 10–15 m/s range, winglets significantly enhance torque and power output. While this increased power generation is beneficial, it is essential to consider the potential impact of the associated increase in thrust force on turbine stability.