Effect of blade tip shapes on the performance of a small HAWT: An investigation in a wind tunnel

Abstract

Aerodynamic performance of a horizontal axis wind turbine blade is affected by its span stacking whether it is two (2D) or three-dimension (3D). The optimization by including swept or/and dihedral at the blade tip tends to enhance its aerodynamic behavior. In order to correctly select the swept angle and anhedral in designing 3D blades, the behavior of the blade geometry variation should be characterized. By using wind tunnel experimentation, modified blades at their tips by swept and anhedral are characterized. Swept tip blade modification only produces weak torque generation while adding anhedral tip blade modification enhances the produced torque significantly. Keywords: Small HAWT, Blade tip shape, Tip loss, Roll-up vortex, Performance