Wave-induced collision loads and moments between a spar-buoy floating wind turbine and an installation vessel
Journal article, Peer reviewed
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Original versionLande-Sudall, D. R., Høyven, T. S., Herfjord, K., & Thuestad, T. C. (2020). Wave-induced collision loads and moments between a spar-buoy floating wind turbine and an installation vessel. Journal of Physics: Conference Series, 1669. 10.1088/1742-6596/1669/1/012009
Spar-buoy floating wind turbines (FWTs) have been deployed at full-scale off the coast of Scotland. However, their deep draught restricts their wider-suitability for assembly and installation at shallow water ports. Here a barge-type installation vessel is investigated experimentally for supporting a FWT such that a draught reduction of up to 30% can be achieved. Tests in irregular waves are conducted to understand the design loads required of a mechanical linkage between the vessel and FWT. Overturning moments increase by over double for a doubling in significant wave height, Hs, and peak overturning moment occurs at the pitch eigenfrequency of the combined vessel and FWT. For Hs=1.5 m, these loads can be accommodated for with a steel truss-frame structure. Collisions between vessel and FWT are also tested for regular head waves and show that, whilst a number of collision forces exceed those of the relevant design standards, these could be reduced to within the existing design limits by use of a fender.