Influence of floater geometry on snap loads in mooring systems for wave energy converters

Johannes Palm, Claes Eskilsson

Research output: Contribution to book/anthology/report/conference proceedingArticle in proceedingResearchpeer-review

Abstract

Mooring systems for floating wave energy converters often rely on floaters to allow for minimum restraints of the body motion in heavy. However, the inclusion of floaters also introduce possible slack-taut scenarios induced by the dynamic response of the floater in relation to the fair-lead point of the mooring. This can increase the occurrence of snap loads. The present study outlines the work to include floaters and sinks into a high-order discontinuous Galerkin model for mooring cable dynamics. Numerical simulations of a mooring leg adapted from the Waves4Power full-scale device are performed, and the results from varying the floater geometry are analysed.
For this case the floater influence on the occurrence of snap loads was clearly evident. There is a strong correlation between floater pitch response and cable slack in the upper mooring cable. For a floater with constant buoyancy, increasing the floater height and thereby increasing the pitch inertia of the floater is shown to decrease the range of frequencies where cable slack occurs. It is illustrated that for some cases, changing floater geometry can avoid slack altogether. A careful design of the floater geometry can thus make a large difference for the dynamic load factor of the
mooring system.
Original languageEnglish
Title of host publicationProceedings of the 13th European Wave and Tidal Energy Conference
Number of pages9
PublisherEuropean Tidal and Wave Energy Conference
Publication dateSep 2019
Article number1375
Publication statusPublished - Sep 2019
EventEuropean Wave and Tidal Energy Conference - Centro Congressi della Stazione Marittima di Napoli, Naples, Italy
Duration: 1 Sep 20196 Sep 2019
Conference number: 13
https://ewtec.org

Conference

ConferenceEuropean Wave and Tidal Energy Conference
Number13
LocationCentro Congressi della Stazione Marittima di Napoli
CountryItaly
CityNaples
Period01/09/201906/09/2019
Internet address
SeriesEuropean Wave and Tidal Energy Conference Series
ISSN2309-1983

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Palm, J., & Eskilsson, C. (2019). Influence of floater geometry on snap loads in mooring systems for wave energy converters. In Proceedings of the 13th European Wave and Tidal Energy Conference [1375] European Tidal and Wave Energy Conference. European Wave and Tidal Energy Conference Series