Wind piezoelectric energy harvesting enhanced by elastic-interfered wake-induced vibration

Inspired by wake induced vibration (WIV) of tandem arranged cylinders, a piezoelectric wind energy harvester with up and down stream interferences is proposed for highway wind resource exploitation. The WIV energy harvester is composed of a piezoelectric cantilever beam and an interference-affected bluff body that attached to the beam tip. The static and elastic interference configurations are investigated to enhance the aerodynamic force of the harvester. The upstream obstacle produces vortices impinging on the energy harvester and interfering with its shedding vortex. The downstream obstacle generates gap push between the harvester and itself. To capture these physical causes, fluctuating lift and drag forces dependent on the motion of the harvester are employed to model the unsteady aerodynamic force. An aeroelastic and electromechanical coupled governing equation is established using the electromechanical extended Hamilton's principle. Computational fluid dynamics is performed to analyze the flow pattern, wake structure and lift coefficient of the WIV wind energy harvester. Wind tunnel experiments investigate the effect of the upstream-wise and the downstream-wise spacings on harvesting power. The analytical model well predicts the wind-tunnel experimental results that the upstream-wise spacing is more important than the downstream-wise spacing. Maximum average powers of 0.169 W, 0.076 W and 0.038 W are harvested by the elastic configuration at the respective wind speeds of 10 m/s, 7.6 m/s and 6 m/s. The theoretical derivations explain that the harvested power by the wake-induced vibration is proportional to the third power of the wind speed. Therefore, the proposed wake-induced vibration in tandem configuration greatly improves the performance of galloping energy harvesting.

Automated summary

A piezoelectric wind energy harvester inspired by wake induced vibration of tandem cylinders is proposed, with optimizations to aerodynamic forces. Experimental results showed that the harvested power is proportional to the third power of wind speed.