Passive flow-field control using dimples for performance enhancement of horizontal axis wind turbine

This paper investigates the effectiveness of dimples on the aerodynamic performance of NREL Phase VI wind turbine. Computational fluid dynamics (CFD) was conducted to simulate the turbulent flow and all the forces acting on the rotor. k-omega shear-stress transport (SST) turbulence model was selected to complete the governing equations and multi-reference frame was used as the computational domain. The computational results were compared with the experimental data and previous studies to ensure its reliability. The effect of different dimple configurations, placed at the suction side of the rotor, on the aerodynamic performance of the rotor blade was investigated in terms of the output torque and axial thrust, coefficient of pressure, and the flow field around the blade cross section in the spanwise directions. The results revealed that, dimpled-surface blade could generate up to 8.41% higher output torque compared to the original blade. The results showed no significant deviation in the axial thrust with the addition of the dimples. The modified surface blade with dimples was proven to enhance the operating performance of a wind turbine.