A comparative study on the numerical simulation of 2-D violent sloshing flows by CCUP and SPH

Sloshing phenomena considered in engineering problems involve violent resonant free-surface flows with strong nonlinear behavior. In such cases, sloshing flows cause local impact pressure. Thus, the prediction of slosh-induced loads becomes an essential element in the design of LNG carriers, LNG related offshore structures, and ships with liquid cargo such as VLCC. Two different numerical methods, i.e., constraint-interpolation-profile (CIP)-based finite difference method called CIP-combined and unified procedure (CCUP), and smoothed-particle-hydrodynamics (SPH) method, were considered to solve violent sloshing problem for the Daewoo Shipbuilding and Marine Engineering Co and MARIN experimental models. The CCUP and SPH methods were suitable to simulate very violent sloshing problem, and both schemes could predict impact pressure with reasonable accuracy on the tank wall. Since the present CCUP method uses two-phase fluid formulation, more realistic movement of the free-surface was simulated such as attachment and splash than the present SPH for single fluid. However, more systematic sensitivity study for physical and computational issues such as compressibility of air and proper detachment on the tank ceiling should be performed to obtain better prediction of impact pressures. The present SPH method provided a less stable solution than the CCUP. The weakest point was in the computation of pressure, but it was applicable to predict the global sloshing-induced force and moment as shown in the roll excitation results. This is an abstract of a paper presented at the Nineteenth (2009) International Offshore and Polar Engineering Conference Proceedings (Osaka, Japan 6/21-26/2009).