Performance enhancement of piezoelectric energy harvesters based on flow-induced vibration via bio-inspired design

To improve the performance of the piezoelectric energy harvester using the traditional square bluff body, this paper introduces a novel biomimetic fish-tail design to capture ambient fluid kinetic energy. This design demonstrates a natural advantage in the formation and shedding of vortices, which is conducive to energy transfer and flow-induced vibration, thereby leading to outstanding performance. A coupled system model was established, and a numerical research method was proposed and validated. Numerical experiments were conducted to investigate the flow-induced vibration and electrical responses of energy harvesters employing fish-tail bluff bodies with varying afterbody inclination angles, alongside a square bluff body configuration. The results indicate that the biomimetic energy harvester with a 20° afterbody inclination angle shows the best performance. The maximum root mean square voltage generated by the energy harvester equipped with the fish-tail cylinder reaches approximately 79.6 V, significantly surpassing the output for the square cylinder (around 33.7 V) within the examined wind speed range. Furthermore, the biomimetic configuration exhibits a remarkable enhancement in output power, with an average increase in 482% and a peak increase in 742% compared to the traditional design. This study provides new insight into designing efficient piezoelectric energy harvesters based on the principles of biomimicry.