Hydro Energy Harvesting

Vortex induced vibrations (VIV) and Galloping are two instabilities which can be utilized to harvest energy. Such flow induced vibrations (FIV) can be utilized to harvest energy from the low speed flows where conventional hydro turbines fail as they require much larger velocity or potential head. The FIV system can be customized to harvest energy in specific velocity ranges as per the availability at the site.

Here, we develop an in-house facility and experimentally investigate the flow induced vibrations in a water tunnel. The experimental setup comprises low friction air bearings mounted on a shaft, springs are used to provide the restoring force, and a 3D printed mounting board to house all the components together. The test section experiencing FIV is connected with a non-contact laser sensor measuring displacement with time. The experimental setup is first validated with a cylinder as the test section, and we could successfully measure the response of all branches of FIV.
Schematic of experimental setup for energy harvesting using FIV

The oscillatory platform is further connected to a magnet, which oscillates inside a fixed coil. The external resistance is optimized to maximize the energy output from the system. A maximum of 9.7 mW of power is generated at a Reynolds number of 17,000 using an external resistance of 88 Ω, which is better than most such systems that have been developed. We are currently exploring several possibilities to increase the amount of energy captured by varying the bluff-body and the energy extraction circuit.