Energy Harness and Wake Structure of “Cir-Tri-Att” Oscillators for Flow-Induced Motion Tidal Energy Conversion System

Abstract

The research focuses on the flow-induced motion (FIM) and energy harness of “Cir-Tri-Att” oscillators (CTAO). The wake was photographed by particle image velocimetry (PIV) to explore wake structures. With the increase of the aspect ratios: the ability of oscillators to galloping under self-excitation or external excitation is enhanced. When ζ = 0.033, U_r = 12.5, the maximum amplitude ratio A* = 2.408 for oscillators with α = 1:1. Moreover, oscillators with higher aspect ratios can bear larger loads, which is conducive to energy utilization and conversion. The maximum power output P_harn = 16.588 W and the optimal efficiency η_harn = 24.706% appear in oscillators with α = 1.5:1. Additionally, In the soft galloping (SG), the wake mode is 4P or 3P. The wake vortex is more broken and its scale increases, but the force effect of the oscillators is better and the oscillation is more stable. The pressure difference makes for a longer oscillation period. This paper summarizes the FIM, energy harness and wake structures of the CTAO under different working conditions, which provides theoretical and data support for the optimization oscillators of flow-induced motion tidal energy conversion system.

Keywords

Tidal energy / Flow-induced motion / Energy harness / Wake structures

Acknowledgments

Results were obtained from State Key Laboratory of Hydraulic Engineering Intelligent Construction and Operation of Tianjin University.

Author Contributions

Conceptualization, X.Y. (Xiang Yan); Methodology, X.Y. (Xiang Yan); Software, J.X.; Validation, L.J.; Formal Analysis, X.Y. (Xu Yang) and S.N.; Investigation, L.J.; Resources, X.G. and X.Y. (Xiang Yan); Data Curation, X.Y. (Xu Yang) and Y.Y.; Writing—Original Draft Preparation, L.J.; Writing—Review & Editing, X.Y. (Xu Yang), Y.Y., X.G. and X.Y. (Xiang Yan); Visualization, L.J. and J.X.; Supervision, Y.Y. and X.Y. (Xiang Yan); Project Administration, Y.Y. and X.G.; Funding Acquisition, X.Y. (Xu Yang), X.Y. (Xiang Yan) and N.S.

Ethics Statement

Not applicable.

Informed Consent Statement

Not applicable.

Funding

The research was founded by National Key R&D Program of China (Grant No. 2022YFB4200702), Tianjin Science and Technology Plan Project (Grant No. 23ZYQYGX00140), National Natural Science Foundation of China (Grant No. 52409085), the Science and Technology Project of Hebei Education Department (Grant No. BJK2023099) and the Hebei Natural Science Foundation (Grant No. E2022402074).

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

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