Influences of bluff body geometries upon performances of piezoelectric wind energy harvesters

Piezoelectric wind-induced vibration energy harvesters (PWVEHs) offer a promising solution for powering wireless sensor networks by converting wind energy into electrical energy. While conventional PWVEHs rely on vortex-induced vibration (VIV) and galloping to work, little has been done to investigate the coupling mechanisms between VIV and galloping and their influences upon energy harvesting performances of flow-induced vibration (FIV). To address this, we propose 36 bluff bodies (BBs) with various frontbody and afterbody shape combinations and conduct FIV experiments in a wind tunnel. The voltage output of each BB is recorded and analyzed based on whether pure VIV, pure galloping vibration, or concurrent VIV-galloping vibrations are involved. Hysteresis analyses are performed for BBs exhibiting concurrent VIV-galloping vibrations. The energy harvesting performances of all BBs are compared to circular and square cross-section BBs, revealing a BB shape that achieved 23.18% and 16. 57% higher maximum output than circular and square BBs, respectively. Computational analysis is conducted to investigate the flow field behind the given BBs. These findings provide valuable insights for developing efficient energy harvesters utilizing VIV and galloping by optimizing the involved BBs.