Vortex-induced vibration piezoelectric energy harvester with arch beam for multi-directional operation and self-powered sensing

Conventional vortex-induced vibration (VIV)-based piezoelectric energy harvesters (PEHs) typically operate effectively only under a single incident wind direction and within a narrow lock-in speed range, resulting in reduced adaptability and efficiency in naturally fluctuating wind conditions. In this study, a VIV-based PEH incorporating an arch beam as a supporting structure is proposed to capture wind energy over a broad range of incident wind directions and multiple lock-in wind speed ranges by activating higher-order vibrational modes. Finite element analysis is first conducted to determine the natural frequencies and corresponding mode shapes of the VIV-based PEHs with both the conventional straight beam and the proposed arch beam configurations. Subsequently, wind tunnel experiments are performed to evaluate the wind energy harvesting performance, including the cut-in wind speed, lock-in wind speed range, incident wind direction range, and electrical output, by leveraging the harvester's multi-modal response. Finally, the superior configuration with a central angle of 3π/4 is selected to demonstrate its application potential, including powering wireless sensors. The results reveal that the proposed harvester can effectively capture wind energy with superior wind direction adaptability and across several lock-in wind speed ranges by activating multiple modes, achieving optimal performance when the second bending mode is excited. Overall, this novel design provides a promising approach for efficiently harvesting wind energy and for powering remote sensing devices under variable natural wind conditions.