Performance of the integrated piezoelectric energy harvester in wake-induced vibration with different cross sections: Circle, rectangle, and triangle

The output performance of wake-induced vibration piezoelectric energy harvesting is closely related to wake characteristics. We used tunnel tests and a two-way fluid–structure interaction method to reveal the influence mechanism of wake characteristics in an integrated double bluff-body piezoelectric energy harvester (PEH) by changing the interference column cross section. The vibration response, flow field, output performance, and energy-conversion efficiency were obtained in the wind speed range of 0–6 m/s. Results indicated that the vibration response and output performance of the device were outcomes of the combined effects of wind speed and bluff-body shape. When U < 3.2 m/s, the turbulence intensity of the wake was enhanced owing to the tip angle of the square column. Thus, the largest displacement and voltage were obtained in the square column. When U > 3.2 m/s, the large velocity gradient behind the cylinder makes it have the best overall performance. The energy-conversion efficiency of PEH initially increased and then decreased with increasing wind speed. The maximum efficiencies of the cylinder at 0.25 m/s were 62.5% and 116.7% higher than those of the square and triangular columns, respectively. When U > 1.5 m/s, the efficiency trend of the triangular column remained stable, whereas those of the cylindrical and square columns displayed an alternating trend. This study, employing a combined experimental and simulation approach, elucidated the electric energy generation patterns of the PEH under wake-induced vibration. It provides a novel energy solution for low-power marine monitoring. This not only lays the foundation for the large-scale application of such technologies but also may support broader marine observation networks.