Energy Harvesting from Energy Harvesting Eel behind Inverted C-Cylinder in Stagger Arrangement

Abstract

Self-powered instruments have gained growing attention from the researchers to make use of renewable energy sources present in our environment, as these are environmentally friendly and have become a part of the modern world. Energy harvesting from a renewable energy source is classified into the macro scale and micro scale. Macroscale includes solar, wind, tidal, geothermal, and micro-scale includes mechanical energy (vibration, deformation), heat, electromagnetic radiation, temperature gradient. The choice of energy source depends on different factors: sensing lifetime, sensing load, amount of energy to be harvested, and storage. In the last several decades, the energy harvesting due to flow-induced fluttering of an energy harvesting eel has attracted interest. When a bluff body is placed in a constant fluid flow. At the interface of fluid and solid, boundary layer is produced because of the no-slip condition. Due to adverse pressure gradient, this boundary layer separates from wall and become an independent vortex structure. The region in which these vortex lies is known to be a wake region. Energy harvesting eel made of piezoelectric polymer flutters when it is placed in the wake region behind the bluff body. This results in electrical energy generation. We experimentally investigate the effect of inverted C-cylinder with different cut angles (1200, 1500, 1800) on energy harvesting and the dynamics of conventional energy harvesting eel by varying streamwise and crosswise distances. The experiment was performed in closed loop water tunnel and free stream velocity of fluid was fixed to be 0.31 𝑚𝑚⁄𝑠𝑠. Energy harvesting eel used consists of PVDF as a piezoelectric material. Large power and amplitude flapping are observed for the conventional piezoelectric eel when it is placed off the midline. We observed that maximum power obtained for 1200 cut angle cylinder is 13.32% more than 1500 cut angle cylinder and 18.24% more than 1800 cut angle cylinder.