Y-type three-blade bluff body for wind energy harvesting

A three-blade bluff body for wind energy harvesting is proposed and designed. The bluff body with a Y-type cross-section is formed by three rigid thin blades and fixed at the free end of a piezoelectric cantilever beam. Simulations and experiments confirmed that this three-blade structure can achieve much higher energy output than a square prism. The output voltages of horizontal harvesters with different half-angles between the two front blades of the bluff body were measured first. The half-angle dramatically affected the performance of the energy harvester. Half-angles between 60° and 80° are found to be the optimal values for generating a high output voltage. In addition, the performance of the harvester can be enhanced when the length ratio of the rear blade to the front blade is in the range of 4/3–5/3. Interestingly, the output voltage of the vertical three-blade harvester was higher than that of the horizontal one and the optimal half-angle in this case was also between 60° and 80°.