Vibration mitigation of wind turbines with tuned liquid damper using fluid-structure coupling analysis

A tuned liquid damper (TLD) is one of the most economically passive vibration control strategies for controlling the wind-induced vibrations of structures such as wind turbines (WT). The literature on fluid-structure interaction limits the scope of analysis to either the influence of wind on tower, or liquid on tank. Meanwhile, it does not consider the applicability of damper installation inside the tower or even inside the nacelle. This study adopts an integrated experimental and numerical approach to find an applicable TLD configuration to mitigate vibrations of a 5-MW wind turbine considering the mutual effects between wind, tower, and liquid damper. It uses the Ansys Fluent module in the tower's TLD and wind-induced vibrations. It starts with wind load simulation, including the vortex shedding effect. Then, it presents the sloshing water behavior and validates it with an experimental model. Parametric study has been conducted to consider the effect of different mass ratios, frequency ratios, and the influence of soil stiffness on the response on the WT tower. The experimental analysis demonstrates TLD's feasibility in mitigating vibration sufficiently with a 40% displacement reduction. A single TLD with a 4% mass ratio can reduce the lateral deformations by 7.32 and 12.5% of WT with fixed and partially fixed end conditions, respectively. While using a configuration of 3 TLDs with a 12% mass ratio extends the fatigue life by 38% and offers a gain in lateral deformations reduction that reached 48.73 and 71.45% for both fixed and partially fixed end conditions.