Energy Harvesting by Vortex-Induced Vibrations in Slender Structures

Abstract

Vortex-induced vibrations (VIV) are self-sustained oscillations of an immerged bluff body strongly coupled with its fluctuating wake. In this paper, energy harvesting by VIV of slender structures is investigated using a wake-oscillator model. The generic case of an infinitely long tensioned cable with periodically distributed harvesters is first investigated. The linear stability analysis of the model is a good tool to understand the strong influence of the different harvesting parameters on the efficiency. As the achieved efficiency is rather high, VIV seem promising as a mechanism for energy harvesting. The more realistic case of a hanging string with a single energy harvesting device at its upper extremity is thus considered. The optimal efficiency is still rather high, travelling waves develop towards the harvester when parameters are in the efficient region of the parameter space, which is identified thanks to a forced analytical calculation.