Influence of met-ocean data integrity on the dynamic performance optimization of floating offshore wind turbines

Applying optimization techniques to hull shape and mooring configuration designs has become an effective way to reduce the life-cycle cost of a floating offshore wind turbine (FOWT). This paper aims to investigate the influence of met-ocean data integrity on the FOWT dynamic performance optimization. Two optimization loops with different levels of met-ocean integrity are set up. In the first loop, the FOWT dynamic performance is evaluated by the long-term response indicators, e.g. the lifetime accumulative fatigue damage at tower. The long-term responses are predicted based on an integrated 25-year met-ocean database which includes 73000 3-hour wind and wave data. In the second loop, the dynamic performance is evaluated by the short-term responses, which are predicted based on the simplified met-ocean data. It includes 41 representative load cases that are selected from the 25-year database. Both loops employ the NSGA-II multi-objective optimization algorithm to find out the Pareto designs that have the best trade-off between dynamic performance and manufacturing cost. By comparing the two optimization results, it is found that the Pareto designs of the first loop tend to have a smaller tower base fatigue than the second. The first loop has smaller mooring fatigue in the high manufacturing cost region, while an opposite trend is seen in the low cost region. These findings demonstrate the importance of met-ocean data integrity to FOWT optimization.