A floating resonant absorber for motion mitigation in floating offshore wind turbines
Please login to view abstract download link
In this study, we propose a concept of floating resonant absorber for motion mitigation of floating offshore wind turbine. This concept has already been proposed for floating offshore wind turbines on spar supports [1] with promising results, while here it is considered the application to a 10 MW offshore wind turbine on a three-spar floating platform [2]. The mass of the floating absorber is a spar floater that floats independently of the the wind turbine in the space between the three spar constituting the three-spar floating platform. The floating absorber and the three spar platform are connected by elastic springs and viscous dashpots calibrated in such a way to mitigate the pitch/roll motion of the floating wind turbine. The calibration is performed in the frequency domain by the well established fixed point theory. The effectiveness of the proposed solution is verified by menas of extensive time domain simulations, considering various configuration of the floating absorber and several combinations of wind-wave conditions. The results demonstrate a considerable effectiveness of the proposed solution in controlling the pitch/roll motion of the floating wind turbine resting on the three-spar platform. A significant advantage in comparison with conventional tuned mass devices is that the absorber is not housed in the nacelle or in the floating platform, allowing to adopt large device mass without adding dead load to the floating wind turbine.