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Liquid sloshing inside tanks of a vessel may result in increased/decreased vessel motions or structural damages. The resonant sloshing motions can be suppressed by using baffles inside a tank. Especially, more energy dissipation is possible by using porous baffles. Here, the effect of dual vertical porous baffles on the sloshing reduction inside a rectangular tank is investigated both theoretically and experimentally. The matched eigenfunction expansion method is applied to obtain the analytic solutions in the context of linear potential theory with porous boundary conditions. The porosity effect is included through inertial and quadratic-drag terms. The theoretical prediction is then compared with a series of experiments conducted by authors with harmonically oscillated rectangular tank at various frequencies and baffle parameters. The measured data reasonably correlate with the predicted values. It is found that the dual vertical porous baffles can significantly suppress sloshing motions when properly designed by selecting optimal porosity, submergence depth, and installation position. [ABSTRACT FROM AUTHOR]

Abstract: The interaction of oblique monochromatic incident waves with a submerged horizontal porous plate has been investigated in the context of two-dimensional linear potential theory. The matched eigenfunction expansion method is applied to obtain the analytic solution. The present formulations, suggested by Molin and Nielsen (2004) and Liu and Li (2011), are compared with the independent solutions using complex dispersion relations and they are proved to be identical. The former approach, however, may be more straightforwardly extended to the case of multi-layer horizontal porous plates. Also, the present predictions are compared with a series of experiments conducted in a two-dimensional wave tank at Jeju National University. By using the empirical relationship between plate porosity and porous parameter obtained by authors (Cho and Kim, 2008), the measured reflection and transmission coefficients reasonably follow the trend of predicted values. The performance of the proposed submerged horizontal porous breakwaters can be significantly enhanced by selecting optimal design parameters, such as porosity, submergence depth, and plate width. The optimal cases are obtained through a systematic parametric study, which illustrates the usefulness of the presently developed analytic solutions. [Copyright &y& Elsevier]

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. [ABSTRACT FROM AUTHOR]

Abstract: The interaction between oblique incident waves and dual submerged horizontal porous plates has been investigated in the context of the two-dimensional linear potential theory including viscous effect through Darcy's law. The matched eigenfunction expansion method(MEFEM) for multiple domains is applied to obtain the analytic solutions. The analytic solutions are verified through comparisons with the independently developed multi-domain BEM(boundary element method) solutions based on simple-sources (second-kind modified Bessel function). The BEM solutions are further used for more general cases including inclined porous plates. Both analytical and BEM solutions are also verified against a series of experiments conducted in a two-dimensional glass-walled wave tank at Jeju National University. In the comparison, the empirical relationship between the plate porosity and porous parameter obtained by Cho and Kim (2008) was successfully applied. The dependence of the reflected and transmitted coefficients on the design parameters, such as porosity, submergence depth, plate width, gap distance, wave heading, inclined angle of the plate, and wave length, is systematically analyzed. It is found that the performance of the proposed dual submerged horizontal porous plates can be significantly enhanced by selecting optimal design parameters for the given wave condition. The upper porous plate plays a major role in wave blocking performance but the presence of lower porous plate may be important when tidal variation is large. [Copyright &y& Elsevier]