Energy harvesting from flow-induced vibration of a low-mass square cylinder with different incidence angles
Open Access
- 1 February 2021
- journal article
- research article
- Published by AIP Publishing in AIP Advances
- Vol. 11 (2), 025126
- https://doi.org/10.1063/5.0037071
Abstract
This numerical study investigates the flow-induced vibration responses and energy harvesting characteristics of a low-mass square oscillator. We first test three typical incidence angles of α = 0°, 22.5°, and 45° with reduced velocities Ur ranging from 3.8 to 26. The most interesting phenomenon is that large-amplitude vibrations can be generated at high reduced velocities, regardless of the angle α. We show that this is because of the following mechanisms: (i) For α = 0°, galloping occurs, resulting in high-amplitude and low-frequency vibrations; (ii) for α = 45°, the cylinder undergoes vortex-induced vibrations (VIVs) without the high-amplitude galloping instability. The unsteady vortex shedding effects are enhanced by a very low mass ratio, leading to “VIV forever” in the tested range of Ur with high-level amplitudes; and (iii) for α = 22.5°, the oscillations in the high-Ur range include both VIV and galloping components. Thus, the large amplitude is caused by the galloping instability and enhanced vortex-shedding effects. Due to the existence of large-amplitude vibrations, the low-mass square cylinder demonstrates the potential and necessary robustness for energy harvesting applications. Overall, α = 45° is the most suitable arrangement for the conversion of power. To further improve the efficiency, we test a 45° cylinder under damping ratios ζ ranging from 0.01 to 0.7. The results indicate that the energy harvesting characteristics are sensitive to the damping ratio when ζ < 0.3. Of all the tested cases, ζ = 0.7 provides the highest average efficiency.Keywords
Funding Information
- China Scholarship Council (201906290110)
- National Natural Science Foundation of China (51809214)
- National Key Research and Development Program of China (2016YFC0301300)
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