Comparison of flow structures for vane and rod type vortex generators on a wind turbine airfoil

Abstract

PurposeThe purpose of this paper is to investigate and compare the effects of rod and vane-type vortex generators for wind turbine applications. In large wind turbine rotors, an attached flow at all sections along the span direction is difficult to achieve which leads to an increase in aerodynamic losses, noise generation, and fatigue stress. Therefore, flow control strategies such as vortex generators (VGs) are beneficial to improve performance.Design/methodology/approachThe benefits of the application of rod-type vortex generators (RVGs) to control flow separation on a wind turbine airfoil are assessed numerically using computational fluid dynamics (CFD). The validation of the computational model is conducted against the experimental data available for the DU96-W-180 wind turbine airfoil equipped with 44 RVGs. In addition, a revised wind tunnel angle of attack (AoA) calibration procedure (based on CFD) is proposed that is applicable for separated flows. A comparison of the RVGs to the conventional vane-type vortex generators (VVGs) is presented for inflow velocity of 30 m/s and AoA leading to significant flow separation. A parametric evaluation of the geometric characteristics of both types of VGs is conducted to quantify the generated streamwise vortices.FindingsThe comparison of the induced flow structures and aerodynamic efficiency enhancements proves that RVGs may be used as an alternative to the more conventional VVGs applied on wind turbine blades for boundary layer separation control.Originality/valueA new type of VG (rod) has been investigated and compared against conventional VG (vanes) for wind turbine applications.