Aerodynamic Influence of Biomimetic Flaps on a Vertical Axis Wind Turbine

To enhance the aerodynamic performance of vertical axis wind turbines (VAWTs), inspired by the slight elevation of trailing-edge feathers in bird wings during landing or gust conditions, a method of deploying a biomimetic flap (BF) structure on the suction surface of a NACA0021 airfoil is proposed. First, the Box-Behnken response surface methodology is employed to construct a sample space for the structural parameters of the BF, with the turbine torque selected as the optimization objective. Second, numerical simulations and quadratic regression analysis are combined to derive the optimal parameter combination for the BF. Finally, computational fluid dynamics (CFD) simulations are conducted to analyze the impact of the BF on the aerodynamic performance of the VAWT. The results demonstrate that the BF angle exhibits the highest sensitivity among all single-factor main effects on torque, while the interaction effect between the BF angle and length shows the greatest sensitivity among all interaction effects. The BF proves more effective at low tip-speed ratios, effectively suppressing dynamic stall phenomena and enhancing blade torque, thereby improving the aerodynamic performance of the VAWT.