A novel vortex-assisted generation system for hydrokinetic energy harvesting from slow water currents

A novel system has been developed that harnesses the phenomena of vortex-induced vibrations (VIV) from a slow current (<0.5 m/s) of water to generate renewable hydrokinetic energy. It utilizes a single degree of-freedom pivoting cylinder mechanism coupled with an electromagnetic induction generator. As a result of observation and concept development, the final prototype includes a stationary cylindrical shedder upstream of the oscillator. The system is referred to as ‘Vortex Assisted Generation’ (V.A.G.) throughout the report. Given the novelty of the system, an extensive investigation has been conducted to identify key parameters and functional relationships between system variables, regarding their effect on output voltage, frequency, and power. A range of flow velocities have been established that instigate system lock-in, where the cylinder oscillates at high amplitude and frequency. For the tested prototype up to 37% of system extraction efficiency has been achieved in the lab conditions.