Session: 16-01-01 Offshore Wind Energy and Renewables

Submission Number: 180561

Assessment of the Dynamic Behavior of Different Mooring Line Configurations for a Semisubmersible-Type FOWT in Deep-Water Fields 

This paper presents an assessment of the mooring lines dynamics of a semisubmersible-type FOWT supporting a 15 MW wind turbine at a water depth of 1000 m. The mooring arrangements assessed consist of six lines, each composed of three segments (chain-polyester-chain), whose configurations were defined through an optimization approach previously described in the literature, which identifies the lightest feasible lines. A total of eight mooring configurations for different anchor radii and total line lengths were investigated for 140 environmental conditions ranging from mild to extreme. The dynamic response of each mooring configuration under each environmental condition was assessed through time-domain simulations using OpenFAST, where the platform motions were represented using RAOs computed using WAMIT, and the mooring line tensions were computed with a lumped-mass model. The analysis focused on the fairlead of the upper chain segments and the top connection of the intermediate polyester segments. Results show that increasing the anchor radius leads to higher amplification factors, defined as the ratio between the maximum and mean line tensions. For a fixed anchor radius, longer mooring lines are associated with lower amplification factors than the shorter lines. In addition, the least loaded lines are the ones that show the highest amplification factors. Finally, among the configurations evaluated, the cases with depth-normalized anchor radius of approximately 1.5 resulted in the lightest mooring systems.

Presenting Author: Jordi Mas-Soler Universidade de São Paulo

Presenting Author Biography: Jordi Mas-Soler is an Assistant Professor in the Department of Naval Architecture and Ocean Engineering at the Escola Politécnica da Universidade de São Paulo. His main research area is hydrodynamics, with a focus on offshore wind.

Authors:

Jordi Mas-Soler Universidade de São Paulo
Giovanni Aiosa Do Amaral Universidade de São Paulo
Salvatore Verde Universidade Federal de Alagoas
Alexandre Nicolaos Simos Universidade de São Paulo
Daniel Fonseca De Carvalho E Silva Petróleo Brasileiro S.A.