Bio-inspired clover-shaped piezoelectric energy harvester with enhanced performance for low-speed wind energy harvesting

Abstract Wind energy is abundant and contributes significantly to power systems, but the effective utilization of low-speed wind energy remains a challenge. Miniaturized wind energy harvesters based on the piezoelectric effect have been recognized as a promising solution for capturing low-speed wind energy. To enhance energy harvesting efficiency over a wide range of wind speeds, this study proposes an innovative bio-inspired clover-shaped piezoelectric energy harvester (BCPEH) modeled after the structure of clover leaves. By varying the relative width ( R L ) of each leaf of the clover-shaped bluff body, four different configurations were designed. To evaluate the output performance, the proposed BCPEH was tested in a wind tunnel. The findings reveal that the BCPEH with R L = 1.5 achieves a maximum output power of 2.08 mW, representing a 258.62% improvement compared to a conventional galloping piezoelectric energy harvester. Notably, the BCPEH with R L = 1.0 features a cut-in wind speed of only 1.6 m s −1 . The development and shedding characteristics of vortices are revealed through computational fluid dynamic simulation. The semi-elliptic leaves of the clover-shaped bluff body significantly affect the vortex shedding mode and spacing at the microscopic level. This work provides valuable insights for designing high-performance, adaptable piezoelectric energy harvesters.