Numerical research on the impact of built-in rectangular poles on the dynamic characteristics of rectangular liquid tanks

Tuned liquid damper (TLD) mitigates excessive vibration responses of offshore platform structures by utilizing liquid oscillation within a tank. However, the conventional pure-water TLD exhibits limited energy dissipation capacity, which is often insufficient to meet structural vibration control requirements. To enhance the damping performance of TLD, the incorporation of internal obstruction devices is necessary. Moreover, when applied to offshore platform structures, the large dimensions of the TLD tank and the significant liquid sloshing forces require robust internal supporting components to ensure safe and stable operation. In this study, an innovative TLD configuration with built-in rectangular poles is proposed. First, based on computational fluid dynamics (CFD), the two-phase flow solver in OpenFOAM is improved by coupling the level set and volume of fluid (VOF) algorithms (CLS-VOF). This improvement effectively suppresses spurious flows and enhances the accuracy of free-surface capturing. The numerical simulation results show good agreement with experimental data, demonstrating the reliability and accuracy of the proposed numerical model. Subsequently, the effects of critical parameters, including the liquid filling level, number of poles, pole installation position, pole blockage ratio, and excitation amplitude, on the nonlinear sloshing behavior of the internal liquid are systematically investigated, establishing a fundamental database of the dynamic characteristics of the rectangular liquid tank with poles. Then, an equivalent mechanical model is developed using the particle swarm optimization (PSO) algorithm to estimate the sloshing frequency and damping performance of the rectangular liquid tank with poles. The theoretical predictions are compared with numerical simulation results to validate the accuracy of the proposed model. The equivalent mechanical model enables rapid and reliable determination of the dynamic parameters of the TLD, providing effective support for the preliminary design and optimization of TLD in engineering applications.