Numerical study on wakes of a butterfly wind turbine and a straight-bladed vertical-axis wind turbine

Abstract

For both a Butterfly Wind Turbine (BWT) and a straight-bladed vertical-axis wind turbine (SB-VAWT, i.e. H-Darrieus wind turbine) assumed having two blades, the same rotor-diameter (D = 750 mm), and the same rotor-height (H = 500 mm), the three-dimensional computational fluid dynamics (CFD) analysis was carried out mainly focusing on the wake recovery. This study shows that the wake recovery of the BWT rotor tends to be faster than that of the H-Darrieus rotor and that the power of the former can be higher than that of the latter. In addition, the positive effects of the blade inclination (twist angle) of the BWT rotor and the rotation-axis inclination of the H-Darrieus rotor on the wake recovery are illustrated.