Abstract
A linear potential flow model of a rotating lift-based wave energy converter is developed by assuming that the lift is generated by a pair of equal and opposite circulations and that the amplitude of motion is small. The linearisation of the hydrodynamics means that the forces can decomposed and expressions for the wave excitation force and radiation damping force are derived independently and shown to be related to each other through the Haskind Relations. The expressions for the forces are used to show that there is an optimum phase and product of circulation and radius of rotation to maximise the wave power extracted, which is equivalent to the optimum phase and amplitude of motion from ‘conventional’ wave energy converter theory. It is also shown that at this optimum condition 100% of the incident wave energy can be extracted. It is shown that the forces are directly proportional to the velocities due to the motion of the vortices, the water particle velocities due to the incident wave, and the water particle velocities induced by the vortices. The effect of the vortex-induced water particle velocities is considered and the importance of including these velocities on the passive generation of circulation, e.g. by hydrofoils, is highlighted. The impact of a suboptimum product of circulation and radius of rotation is also investigated and shown that the power capture is not highly sensitive to the optimal conditions in the same way as ‘conventional’ wave energy converters.
| Original language | English |
|---|---|
| Pages (from-to) | 37-44 |
| Number of pages | 8 |
| Journal | International Marine Energy Journal |
| Volume | 6 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - 20 Dec 2023 |
Bibliographical note
Funding Information:Manuscript submitted 24 November, 2022; accepted revised 12 May 2023, published 14 December 2023. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 licence (CC BY http://creativecommons.org/licenses/by/4.0/). Unrestricted use (including commercial), distribution and reproduction is permitted provided that credit is given to the original author(s) of the work, including a URI or hyperlink to the work, this public license and a copyright notice. This article has been subject to single‐blind peer review by a minimum of two reviewers. This work was completed as part of the LiftWEC project, which has received funding from the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No 851885. M. Folley is with ARR Ltd., previously at the School of the Natural and Built Environment, Queens University Belfast, Northern Ireland (e‐mail: [email protected]). P. Lamont‐Kane is with the School of the Natural and Built Environment, Queens University Belfast, Northern Ireland (e‐mail: p.lamont‐[email protected]). C. Frost is with the School of the Natural and Built Environment, Queens University Belfast, Northern Ireland (e‐mail: [email protected]). Digital Object Identifier: https://doi.org/10.36688/imej.6.37‐44
Publisher Copyright:
© 2023, European Wave and Tidal Energy Conference. All rights reserved.
Keywords
- circulation
- design
- hydrodynamics
- hydrofoil
- lift
- wave energy
ASJC Scopus subject areas
- Oceanography
- Renewable Energy, Sustainability and the Environment
- Ocean Engineering
Access to Document
- A linear hydrodynamic model of rotating lift-based wave energy converters
Copyright 2023 the authors. This is an open access article published under a Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited.