The shape design and analysis of floating offshore wind turbine structures with damper structure and shallow draft

Abstract

This paper aims to investigate the shape design of floating offshore wind turbines (FOWTs) of the 5MW class both numerically and experimentally. The shape design structure should be considered in order to increase the operable water depth by having a draft shorter than the typical spar structure and a more cost-effective construction. A series of parametric studies of FOWTs has been carried out by numerical analysis using a higher-order boundary element method (HOBEM) in the frequency domain. In the parametric studies, the wind turbine platform with a truss spar shape and a large damping structure was found to have the smallest motion and acceleration responses in waves. The numerical results for the selected shape design of FOWTs were validated by model test data on motion responses and acceleration at the nacelle responses in several regular and irregular waves. The results of the proposed model structure have been compared with the results of a spar-type structure of the same class, the 5MW OC3-Hywind. Finally, shape designs of FOWTs that improve global performance and technical feasibility are also discussed. ？ 2014. The International Society of Offshore and Polar Engineers.