Numerical simulation of violent sloshing by CIP method with experimental validation

The forces acting on the tank structure from the moving fluid can be large enough to provoke local structural deformation or damage. This is a very dangerous situation, especially on board LNG carriers (membrane type). Evaluation of sloshing loads is a key point in the design of ship liquid cargo tanks since when the tank is excited at near-resonance frequencies, violent motions of the liquid can occur. A new computational fluid dynamics simulation approach is used to challenge the sloshing problem. Results by both CIP and CIP-CSL3 schemes for other excitation periods and dependency checks for the various parameters involved. Even though both methods principally agreed, CIP-CSL3 method gives predictions, much closer to experimental values than the originally developed CIP method. The only difference between them from numerical point of view is the interface capturing method, modified to conservative form in the CIP-CSL3 method. Therefore, good prediction of the interface is also crucial for the prediction of impact pressures. The numerical diffusion of the CIP method, applied to simulation of velocities is not so important and the method can be used, when conservation is not a key-factor in the solution. However, if the CIP-CSL3 scheme is applied also to velocities, probably a further refinement of the results can be obtained. This is an abstract of a paper presented at the 15th International Offshore and Polar Engineering Conference (Seoul, Korea 6/19-24/2005).