ANTI-SLOSHING EFFECTS OF LONGITUDINAL PARTIAL BAFFLES IN A PARTLY-FILLED CONTAINER UNDER LATERAL EXCITATION

摘要

This study is aimed at analysis of transient lateral slosh in a partially-filled cylindrical tank with different designs of longitudinal partial baffles using a coupled multimodal and boundary-element method. A boundary element method is initially formulated to solve the eigenvalue problem of free liquid slosh, assuming inviscid, incompressible and irrotational flows. Significant improvement in computational time is achieved by reducing the generalized eigenvalue problem to a standard one involving only the velocity potentials on the half free-surface length using the zoning method. The generalized coordinates of the free-surface oscillations under a lateral excitation are then obtained from superposition of the natural slosh modes. The lateral slosh force is also formulated in terms of the generalized coordinates and hydrodynamic coefficients. The validity of the model is illustrated through comparisons with available analytical solutions. Two different designs of longitudinal baffles are considered: bottom- and top-mounted baffles. The effect of different baffle designs on the normalized slosh frequencies, modes and lateral force are investigated. It is shown that the multimodal method yields computationally efficient solutions of liquid slosh within moving baffled containers. The results suggest that the effectiveness of baffles in suppressing the liquid oscillations is strongly affected by the baffle length relative to the free-surface height. The top-mounted baffle yields the greatest effectiveness, when it pierces the free-surface. The bottom-mounted baffle, however, may not be considered as an efficient mean for controlling the liquid slosh in tank vehicles where the liquid fill height is above 50%.