IMPROVING VIVACE PERFORMANCE WITH FORCED CYLINDER ROTATION

VIVACE (Vortex Induced Vibration for Aquatic Clean Energy) is a system for harvesting kinetic energy from a slow-moving fluid and converting it to electrical energy through the phenomenon of vortex-induced vibration (VIV). VIV causes a submerged, elastically-mounted, cylindrical body to oscillate in a direction normal to the incoming flow, thus allowing it to drive a generator. A body of research exists regarding the use of forced-rotation about the longitudinal axis of a stationary cylinder to enhance the forces exerted upon the body by VIV. Adding the element of forced-rotation to VIVACE could improve the energy-harvesting performance. An experimental apparatus was designed, built, and tested. Synchronization between the force imparted to the cylinder by vortex shedding and the force imparted by the rotation of the cylinder was found to be difficult to achieve. Forced-rotation mostly resulted in a reduced average power output. A notable exception occurred when the forced cylinder rotation was able to enter synchronization at a flow speed too high to allow for oscillation due to VIV alone. Continued functionality when oscillation would normally have decayed into small, random jumps in displacement allowed average power output to be increased by 291% at with the addition of forced rotation.<p></p>