Investigation on the damping of rectangular water tank with bottom-mounted vertical baffles: Hydrodynamic interaction and frequency reduction effect

Abstract

Internal obstructions are commonly employed in Tuned Liquid Damper (TLD) tanks to produce sufficient inherent damping for improving its vibration control performance. However, the hydrodynamic interaction between obstacles has a significant effect on damping ratio of liquid sloshing when the obstacles are becoming close to each other. At the same time, the natural sloshing frequency of the water tank decreases because of the added mass produced by these obstacles. By adopting potential flow and linear wave theory, a linearized analysis model is proposed in this paper to estimate the damping ratio of rectangular water tank with bottom-mounted vertical baffles. The formula of its damping ratio is then further modified to take into account the effect of hydrodynamic interaction between vertical baffles on the fluid velocity and the added mass coefficient. In this study, reduction in the natural frequency of liquid sloshing due to vertical baffles is also investigated in detail. Shaking table tests were conducted on scaled models of the rectangular tank with bottom-mounted vertical baffles to validate the accuracy of the proposed analytical model in this study. Parametric studies are performed to study the effect of the distance between vertical baffles, different water depth ratios, various sinusoidal excitation amplitudes, and the different number of bottom-mounted vertical baffles on the damping ratio. The analyzed results showed that good agreement between the proposed analytical solutions and the experimental results was found. The study also showed that the proposed methodology can effectively estimate the damping ratio by considering the hydrodynamic interaction and natural frequency reduction effect due to the installed bottom mounted vertical baffles.