Bio-inspired aerofoils for small wind turbines

Abstract

This paper investigates the effectiveness of modifying the design of wind turbine blades for small wind turbines. Taking inspiration from nature, the two modifications explored were spanwise corrugations of the blades inspired by a dragonfly’s wing structure, and flexible blades inspired by the shape-morphing of birds and insect wings that adapt to the air conditions. Two types of corrugations were tested in a wind tunnel with the results that the corrugated nature appeared to have desired effects on delaying stall by 4° and reduced the detriment of post-stall behaviour. In addition, the corrugated skin displayed similar characteristics to the control aerofoil, with a small reduction in the peak lift to drag ratio of 7.3%. In the second section, a rigid turbine blade was compared a semi-flexible and fully flexible blade by altering the Young’s modulus using the QBlade simulation tool. Although, spanwise deflection was high in the flexible blade, a reduction in the peak stresses was shown.