EVALUATING THE EFFECT OF MULTIPLE VERTICAL ORTHOGONAL BAFFLES ON SLOSHING PHENOMENON IN RECTANGULAR TANKS SUBJECTED TO 3-DIMENSIONAL EARTHQUAKE EXCITATIONS

One of the most important phenomena in liquid storage tanks, subjected to earthquake excitations, is sloshing which can cause severe damages, particularly to tank’s roofs. Recent studies on rectangular tanks have proven that using multiple vertical baffles can reduce the sloshing effect to a great extent. However, in those studies baffles have been considered to be just in one direction perpendicular to the propagation direction of the main sloshing wave. In this study the effect of using Multiple Vertical Orthogonal Baffles (MVOB), consisting of one and two baffle(s) in each main direction, parallel to the tank side, has been investigated. For this purpose several cases of Time History Analysis (THA), using three-component accelerograms of a set of selected earthquakes have been used. For investigating the dynamic behavior of impounded water the Volume of Fluid (VOF) method has been employed, which uses an advection algorithm for the volume of fraction, varying from zero to one for each element. Precision of the numerical modeling and VOF analyses has been verified by some experimental results from an independent previous study. For numerical analyses some far-source earthquake records which can intensely excite the sloshing phenomenon have been considered. Numerical results obtained by THA show that using just two pairs of MVOB can reduce the maximum water level around 40% for most earthquakes. The effects of vertical ground acceleration in the variation of sloshing as well as hydro-dynamic pressure also have investigated, and it can be said that the vertical component of ground motion does not have much effect on sloshing height, while its affects hydro-dynamic pressure to some extent, leading to increase in the shear forces and bending moments in walls up to 40%.