Comparative Study on Aerodynamic Performance of VAWTs with Different Airfoils Under Dimple-Gurney Flap Synergistic Control

The combined control method of dimples and Gurney flaps has proven effective in enhancing the power coefficient of Vertical Axis Wind Turbines (VAWTs). However, the adaptability of this combined control structure to different airfoil geometries remains unclear. This paper investigates the aerodynamic characteristics of the Toward-Outside Dimple-Gurney Flap (TO-DGF) on three typical airfoils: NACA0021, NACA0012, and S1046. A dynamic flow field prediction model was established using the Lattice Boltzmann Method (LBM) combined with Wall-Modeled Large Eddy Simulation (WMLES). The Taguchi experimental design was employed to analyze the sensitivity of aerodynamic performance to airfoil type, Gurney flap position, and Gurney flap height. The results indicate that the airfoil type is the most critical factor affecting the power coefficient CP, contributing significantly to the performance variance. Specifically, the NACA0021 airfoil demonstrated optimal performance in suppressing dynamic stall. Furthermore, the optimal DGF position varies with the tip speed ratio (TSR): placing the structure at 0.05C and 0.15C from the trailing edge yields the best aerodynamic performance for low (TSR = 1.5) and medium (TSR = 2.4) TSRs, respectively. This study provides a valuable reference for the structural design of high-efficiency VAWT blades within the investigated TSR range.