Simulation of liquid dynamics in an LNG tank is studied numerically. The applied CFD code solves Navier-Stokes equations and uses an improved Volume of Fluid (iVOF) method to track movement of fluid’s free surface. Relative advantages of using two different fluid models, single-phase (liquid+void) and two-phase (liquid+compressible gas) are discussed, the latter model being capable of simulating bubbles and gas entrapped in liquid. Furthermore, the 1st and 2nd order upwind differencing schemes are used with both physical models leading to a total of four possible approaches to solve the problem. Numerical results are verified against experimental data from large scale (1:10) sloshing experiments of 2D section of an LNG carrier. The CFD vs. experiment comparison is shown for tank filling rates of practical interest, ranging from 10% to 95%, and includes both fluid height and fluid pressure exerted on tank walls. A visual comparison in form of computer animation frames, synchronised with camera-made movies taken during the experiments is included as well. Finally, an exhaustive computational grid convergence study is presented for lower filling rates of the tank.
