Hydroelastic response and electromagnetic energy harvesting of square oscillators: Effects of free and fixed square wakes

• Published in: Energy (Oxford) Vol. 263; p. 125982
• Main Authors: Tamimi, V., Esfehani, M.J., Zeinoddini, M., Seif, M.S., Poncet, S.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.01.2023
• Subjects: electric current; Electromagnetic power; energy; Energy harvesting; Flow-induced vibrations; Galloping; hydroelectric power; Tandem square oscillators; Upstream wake; Energy harvesting; Tandem square oscillators; Flow-induced vibrations; Electromagnetic power; Upstream wake; Galloping
• ISSN: 0360-5442
• DOI: 10.1016/j.energy.2022.125982

The unbounded linearly increasing responses in galloping instability make sharp-edge oscillators a beneficial solution for bladeless energy harvesting. While the performance of single square oscillators has been the subject of several studies in the past, there is still little knowledge about their hydrokinetic energy performance in tandem configurations. An optimal oscillator should display high performance in a group when all bodies are free to harness energy. In this study, the energy harvesting performance of square oscillators is examined in multiple tandem configurations under free and fixed square wakes. The harmonic oscillator model is coupled with the electromagnetic transducer to evaluate the performance of the system at the optimum coupling coefficient. For a single galloping square, flow interference by a similar upstream square affects the fluid elastic response of the oscillator and degrades its overall energy harvesting performance. The upstream fixed wake is productive in terms of efficiency (123% increase) but counterproductive for the electrical current and electromagnetic power. The free square wake generally diminishes both the power and efficiency. For a double tandem oscillator device, the synergy of tandem configuration at close spacing improves the maximum efficiency of the energy harvester by 97% as compared to two separate isolated oscillators. •Upstream interference changes the galloping response into combined resonance-WIV.•Fixed square wake improves the efficiency but reduces the harnessed power.•Free square wake is counterproductive for both power and efficiency.•The synergy of tandem configuration considerably rises the system efficiency.