Parametric study of caudal fin shapes for vortex-induced vibration (VIV) energy harvesting

Renewable energy from water has gained popularity due to its ease of conversion into mechanical energy. When water flows around a circular cylinder with a Reynolds number ranging from 300 to 300,000, it generates a phenomenon known as the Kármán vortex street, which can be utilized in the design of energy harvesting devices. One such device that utilizes vortex energy is a piezoelectric system attached to a flexible beam, where the power of the harvested energy is directly related to the deflection of the beam. The biomimicry of caudal fins is applied to the end of flexible beam to improve the efficiency of the device. The fork types of caudal fin are investigated based on four kinds of fish: Bluefin Trevally, Bigeye Trevally, Humpback Snapper, and Great Barracuda. In this research, surface area, length, height, aspect ratio, mass, and center of mass are controlled to avoid any advantageous influences on the shapes. A Reynolds number of 32,500 and a free stream velocity of 0.5 m/s are used. The simulation is based on Computational fluid dynamics (CFD) and the Finite Element Method (FEM) to investigate the Fluid-Structure Interaction (FSI) using Altair HyperWorks softwares. The results show that the Bluefin Trevally gives the highest equivalent power and beam displacement at the same monitoring point, with 87.92 % improvement in displacement and 261.40% improvement in equivalent power compared to the normal rectangular shape of the beam.