Enhancement of the Piezoelectric Cantilever Beam Performance via Vortex-Induced Vibration to Harvest Ocean Wave Energy

Abstract

Renewable and sustainable energies exhibit promising performance while serving as the power supply of a wireless sensor especially located in marine waters. Various microgenerators have been developed to harvest wave energy. However, the conversion ability from a dynamic oscillating source of wave is crucial to enhance their effectiveness in practical applications. In this paper, a new piezoelectric converter system is proposed to harvest the kinetic energy from ocean waves. The vortex-induced effect in an air channel enhances the vibration performance, improving the energy harvesting efficiency. The system comprises an oscillating water column (OWC) air chamber, a bluff body, and a piezoelectric piece for electromechanical transduction. The fluid–solid–electric coupling finite element method was used to investigate the relation between the output voltage and geometrical parameters, including the size and position of the piezoelectric cantilever beam, which is based on the user-defined function of the ANSYS. It is found that the bluff body in the outlet channel above the air chamber induced high-frequency vortex shedding vibration. The regular wave rushed into the air chamber with a frequency of 0.285 Hz and extruded the air across the bluff body in the outlet channel. This incurred the fluctuation of the air pressure and excited the piezoelectric cantilever beam vibration with a high frequency of 233 Hz in the wake region. Furthermore, a continuous electrical output with a peak voltage of 6.11 V is generated, which has potential applications for the wireless sensors on the marine buoy.