Investigation of the aerodynamic characteristics of horizontal axis wind turbine using an active flow control method via boundary layer suction

Abstract

The boundary layer suction (BLS) has the merit of effectively suppressing the formation and development of separation vortices by removing low-momentum fluid occurs on the leading-edge of airfoil suction surface. The present paper numerically investigates the impacts of BLS on the aerodynamic performance of a horizontal axis wind turbine (HAWT). First, the dynamic mode decomposition method is adopted to gain an insight into the improvement mechanism of BLS control by analyzing the flow patterns of a two-dimensional S809 airfoil. Subsequently, the BLS is arranged on a NREL Phase VI reference turbine to study the power increment and flow field characteristics, and the effects of different working angles αs and momentum coefficients Cμ are investigated at different tip speed ratios (TSRs). The results indicate that the use of BLS control can increase the pressure difference between the suction surface and the pressure surface, raise the peak negative pressure at the leading edge and shift the airfoil flow separation point backwards, and thus effectively enhance the stability of the flow field. Furthermore, the BLS control can significantly improve the power extraction at low to medium TSR if this active device is appropriately implemented on the HAWT.