Sloshing reduction in a swaying rectangular tank by an horizontal porous baffle

Abstract Sloshing occurs in a tank containing liquid with free surface. It may result in resonant liquid motions causing carrier-vessel instability or structural damage of tank walls. The horizontal porous baffle is capable of dissipating the sloshing energy and reducing the sloshing pressures acting on tank walls. In the context of linear potential theory, the MEEM (matched eigenfunction expansion method) is applied to obtain the analytic solution for the sloshing with porous horizontal baffle. A BEM (boundary element method) with the porous boundary conditions is also independently developed for double checking and the application to more general cases. Two baffle positions at the center and at both walls of a rectangular tank are considered for various porosities, lengths, and submergence depths. The theoretical prediction is then compared with a series of experiments conducted by authors using harmonically oscillated rectangular tank with various baffle porosities and submergence depths. The measured data reasonably correlate with the predicted values. It is found that horizontal porous baffles installed at both tank walls significantly suppress violent resonant sloshing responses compared to one installed at the tank center. Through parametric study using the developed numerical tools, the optimal porosity, length, and submergence depth can also be determined.