An enhanced underwater piezoelectric energy harvester with Y-shaped attachments for low-speed water flow

Purpose The purpose of this paper is to develop an enhanced underwater piezoelectric energy harvester with Y-shaped attachments, utilizing flow-induced motion to scavenge water flow energy for the sustainable powering of electronic sensors in the ocean. Design/methodology/approach The proposed harvester consists of a substrate beam, piezoelectric sheet, a bluff body and Y-shaped attachments. When the low-speed water flow passes through the Y-shaped bio-inspired bluff body, period vortex shedding induced the vibration of piezoelectric beam, thereby generating electrical output. A theoretical model based on lumped parameter and Van der Pol model is developed. The prototype of the harvester was fabricated and a series of underwater experiments were carried out to investigate the influences of the angle of Y-shaped attachments and flow speed on the output performance. Findings At a flow speed of 0.575 m/s, the harvester achieves an optimal peak-to-peak voltage of 100V and a maximum output power of 0.304 mW at the Y-shaped attachment angle of 120°, corresponding to a 1116% power enhancement compared with the harvester with smooth-surface bluff body. Originality/value Experimental findings reveal that once the flow velocity surpasses a specific critical value, the output of the harvester incorporating Y-shaped attachments on the bluff body is markedly amplified, with the rate of enhancement escalating substantially as the flow velocity increases. This study presents a feasible approach to generate renewable electricity efficiently from low-speed water flow for self-powered undersea monitoring sensors.