Output Power and Wake Flow Characteristics of a Wind Turbine with Swept Blades

To study the output power and wake flow characteristics of a wind turbine with swept blades, taking the blade tip offset and the location of the sweep start as two variables, the straight blade of the DTU-LN221 baseline airfoil was optimally designed with sweep. Then the designed wind turbine was numerically simulated, and the swept blade with the best optimal output power characteristics was selected for the wind tunnel test. The results indicate that for both forward and backward swept blades, increasing the blade tip offset and the sweep start location could decrease the power and thrust coefficients. Compared with the backward swept design, the forward swept design significantly improved the blades’ power characteristics. By adopting swept blades instead of straight blades, wind turbines could generate more power at high tip speed ratios, especially in yaw conditions. The streamwise velocity recovery of the wind turbine with swept blades was slower than that with straight blades as the lateral velocity near the wake region was higher than that with straight blades. Besides, the wind turbine with swept blades had a greater turbulence intensity of the wake near the wake center than that with straight blades with or without yaw condition.