Parametric Analysis of an Energy-Harvesting Device for a Riser Based on Vortex-Induced Vibrations

An energy-harvesting device for a riser based on vortex-induced vibration is proposed to overcome the power supply problem for a marine deep-water riser-monitoring device. To estimate the upper limit of its energy-capture efficiency, as well as the weight and size of the device designed, a discrete model of the riser was configured. With the experimental settings of Stappenbelt and Blevins, vortex-induced vibrations of the discrete cylinder with two degrees of freedom were simulated, and the parameters affecting the energy-acquisition efficiency of the riser were analyzed. The analysis of the dimensionless amplitude ratio showed that this ratio for the system decreased with increasing mass ratio and damping ratio. An analysis showed that the influences of the damping ratio on the energy-capture efficiency were different under medium and low-mass-ratio conditions. A maximum value of 38.44% was achieved when the mass ratio was 2.36 and the damping ratio was 0.05.