CFD-based study on TMDI performance in mitigating low-frequency vertical vortex-induced vibrations

To evaluate the performance of tuned mass damper inerter (TMDI) on mitigating the low-frequency vertical VIV responses of bridges, a CFD-based numerical simulation method for solving the responses of the fluid-structure-TMDI coupled system is proposed in this study. The VIV responses of a 4:1 rectangular cylinder under different TMDI and structural parameters are investigated. It is found that the VIV amplitude of the controlled structure is sensitive to the natural-frequency ratio of TMDI to structure ( f ∗) and the damping ratio of TMDI ( ξ 2 ). For the concerned ranges of the mass ratio of damper to structure from 0.005 to 0.010 and the inerter-induced damper mass amplification factor from 5 to 10, the optimal f ∗ and ξ 2 are within the ranges of 0.990–0.995 and 1.0 %–2.0 %, respectively. The difference in the mitigation effect between the CFD-based model and the empirical VIV force model is highlighted. The geometric and frequency scaling ratios has little effect on the mitigation effect, and thus can be artificially set as needed. The proposed method enables precise setting of system parameters and directly solves the fluid-structure interactions, thereby providing an effective approach for the TMDI design in mitigating low-frequency vertical VIV of bridges.