Hydrodynamic Performance and Energy Capture Characteristics of a Floating Inner Rotor Wave Energy Device

Abstract

The development of efficient wave energy converters (WECs) is essential for harnessing marine renewable energy, particularly in regions with low wave energy flux. This study investigates a floating WEC with an internal eccentric rotor designed to enhance energy capture efficiency. The device consists of a floating body for wave energy absorption, an internal rotor for mechanical-to-hydraulic energy conversion, and a mooring system for stability. A numerical model was developed and validated against wave tank experiments, showing good agreement in peak values and amplitudes. Frequency-domain analysis examined the effects of structural parameters, draft, and center of gravity offset on hydrodynamic characteristics, while time-domain analysis evaluated the impact of rotor mass and power take-off (PTO) damping on energy capture. Multi-parameter optimization led to an improved structural design, increasing instantaneous power output by 150% and total power output by 108%. These findings provide a basis for further optimization of WECs in low-energy wave environments.

Keywords

Wave energy / Wave energy converter / Eccentric inner rotor / Hydrodynamic performance / Energy conversion efficiency

Acknowledgments

Special thanks go to Yanjun Liu, Gang Xue, and their research team at Shandong University for providing valuable experimental data and results that contributed to validating our numerical simulations. The authors also wish to express their sincere gratitude to CIMC Offshore Engineering Research Institute Co., Ltd. for their institutional support, and Dahui Liu for his valuable technical guidance. We greatly appreciate their support and collaboration.

Author Contributions

C.W.: Formal analysis, Model development, Writing original draft. Z.H.: Visualization. C.Y.: Conceptualization, Formal analysis, Methodology, Writing original draft, Project administration, Funding Acquisition. W.Z.: Software, Validation, Model development. L.J.: Conceptualization, Writing review & editing, Project administration, Supervision, Funding Acquisition.

Ethics Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Data will be made available on request.

Funding

This paper is financially supported by the National Natural Science Foundation (Grant No.52101306, 52101326), the National Science Foundation of Shandong Province (Grant No. ZR2021QE121), the British Council (BRI JOINT project) and EPSRC ResIn project (EP/R007519/1), and Harbin Engineering University (award to Chang Wan for studying abroad at University of Queensland).

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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