Effects of lateral wind gusts on vertical axis wind turbines

Abstract

This paper investigates the effects of lateral wind gusts on the aerodynamic performance of vertical axis wind turbines. A synthetic approach coupling computational fluid dynamics (CFD) simulations and the double multiple streamtube method is utilized to calculate vertical axis wind turbine performance. For simulating the wind gust response, the resolved gust approach (RGA) models the gust transport throughout the wind field. The effects of wind gusts on the effective wind velocity, angle of attack, torque and power performance are evaluated. The presence of gusts slightly changes the effective wind velocity and angle of attack. Lateral gusts increase the angles of attack in the upwind half period causing premature flow separations in the flowfield, while suppress flow separation by decreasing the angles of attack in the downwind period. The mean torque and power of the three-bladed turbines are enhanced by the lateral sharp-edge gust of 2 m/s by 5% in comparison to the steady wind. Reducing the number of blades to one and doubling the gust velocity make the performance further enhances by 14.7% and 34%, respectively. Finally, the effects of several gust shapes are investigated and discussed.