Passive Inerter-Based Network Self-Induced Oscillations Damping for Barge-Type Floating Offshore Wind Turbines

This contribution analyses the influence of a passive inerter-based network on the 5MW NREL FOWT with a barge-type foundation when the system is subjected to the specific problem of self-induced oscillation. The concept of implementation of an inerter-based network combined with a standard tuned mass damper (TMD) in the nacelle is here presented with the objective of demonstrating the effectiveness of the introduced network in satisfactorily reducing the amplitude of the self-induced oscillations in comparison to the case of the FOWT system fitted with only a TMD. Major improvements in the overall structural stability were found with a suppression rate ranging from 49% to up to 86%, in the wind velocities of interest, when the phenomenon may occur. Moreover, it was shown that the inerter installed in the nacelle reduces the overall natural frequency of the system by over 56%.