Dynamic Analysis of Shared Moorings in Different Wind Farm Layouts

Abstract

The effects of shared mooring in offshore wind farms are investigated through numerical simulations in the present study. Different farm layouts are modelled and tested in SIMA coupled dynamic analysis software with three and four floaters. The wind turbine and the platform are based on the OC3 project from NREL: a 5-MW wind turbine and a spar floater with a 120-m draft. The water depth is 320 m, and the environmental loads are defined for an average operational condition. Firstly, the static results of the mooring line tension at the fairleads and anchors from the numerical model are compared with the values from the open-source MoorPy code. Then, domain simulations are conducted for three hours, and the dynamic behaviour of the floaters is analysed with a focus on surge and pitch motions. In addition, the dynamic stiffness effects of the polyester in the shared mooring line are considered in the SIMA simulations. The mooring line tensions are analysed, determining the global maximum tension across all systems. Results show that designs with two windward legs have significantly lower anchor mooring line tensions than those with a single windward leg, with no relevant variation in platform surge and pitch. Thus, the former systems are preferable for further investigation.

Keywords

Spar platform / Shared mooring / Offshore energy / Wind farm / Mooring dynamics

Acknowledgements

This work was performed within the scope of the Strategic Research Plan of the Centre for Marine Technology and Ocean Engineering (CENTEC), which is financed by the Portuguese Foundation for Science and Technology (Fundação para a Ciência e Tecnologia—FCT) under contract UIDB/UIDP/00134/2020.

Author Contributions

Conceptualization, S.W. and C.G.S.; Methodology, M.V.B., F.J.V., J.D., S.W. and C.G.S.; Software, M.V.B., F.J.V., J.D., S.W. and C.G.S.; Validation, M.V.B., F.J.V., J.D. and S.W.; Formal Analysis, M.V.B., F.J.V. and J.D.; Investigation, M.V.B., F.J.V., J.D.; Resources, S.W. and C.G.S.; Data Curation, M.V.B., F.J.V., J.D., S.W. and C.G.S.; Writing—Original Draft Preparation, M.V.B., F.J.V., J.D. and S.W.; Writing—Review & Editing, M.V.B., F.J.V., J.D., S.W. and C.G.S.; Visualization, M.V.B., F.J.V. and J.D.; Supervision, S.W. and C.G.S.; Project Administration, C.G.S.; Funding Acquisition, C.G.S.

Ethics Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Access to the data examined in this study can be obtained by contacting the corresponding author.

Funding

This research received no external funding.

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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