Numerical analysis of passive toroidal tuned liquid column dampers for the vibration control of monopile wind turbines using FVM and FEM

The toroidal tuned liquid column damper (TTLCD) is a recently developed multidirectional vibration control device. This paper investigates the TTLCD for the vibration control of monopile fixed-bottom offshore wind turbines. The TTLCD with its circular versatile configuration can match the geometrical shape of wind towers and be tuned to control wind, wave and earthquake induced flexural tower vibrations. An effective numerical framework accounting for the liquid flow and sloshing as well as two-way fluid-structure interaction is developed for the TTLCD-structure system. Its accuracy is validated by comparing the numerical results with experimental ones. The design procedures of the TTLCD for monopile wind turbines are illustrated in detail. The control performance of the TTLCD under wind, wave and seismic loads is presented. The results show that the TTLCD can control the structural responses in both fore-aft and side-side directions simultaneously. Furthermore, it is revealed that for wind-induced vibrations, the control performance relies on the wind velocities and the related frequency components.