Numerical Analysis of Sloshing Problem

Many studies have been reported for the sloshing analysis in liquid containers. One of the major concerns in the marine hydrodynamic field is the accurate prediction of impulsive load on internal structures. During violent sloshing, the sloshing-induced impact load can cause a critical damage on tank structure. Such damage cases have been reported for oil tankers, LNG carriers and bulk carriers. Recently, this problem becomes an important issue in FPSO design. Many analytical and experimental studies on sloshing were performed in the 1950's and 1960's for the tank design of space vehicles. In the 1970's and early 1980's, the sloshing problem became an important issue in the design of the liquified natural gas (LNG) carriers. Some numerical methods were applied during this time, and such studies can be found in the works of Faltinsen[2], Bridges[1], Mikelis and et al[5]. Some Japanese researchers have continued the study, and many interesting results have been introduced for the twoand threedimensional sloshing problems. Recently some computational results using the general-purpose flow simulation programs, like FLOW3D, have reported for the sloshing analysis. However, the application of the generalpurpose programs may be not proper for the prediction of impulsive loads, since the typical numerical treatment of wall condition can result in unrealistic flow simulation. In this study, a numerical method has been applied for the simulation of fluid flows in the twoand threedimensional tanks. The global fluid motion is of interest and local nonlinear phenomena are not considered in detail. The method of solution is a finite difference method, adopting staggered grids. The free surface profile is assumed to be single-valued, so that SURF scheme is applicable to the numerical implementation of free-surface boundary condition. The numerical computation has been carried out for a few models which experimental or other computational results are available. The present results include the computation of impact pressure on tank ceiling. Moreover, the developed computer program was extended to the real-ship application.