Simulation of the Sloshing In the Prismatic Gas Tank After Impact Interaction of the Vessel With Ice Barrier Available to Purchase

Changing the trajectory of the vessel (including after impact interaction with an ice barrier) in the cargo tanks leads to the oscillatory motion of fluid, called sloshing, in the cargo tanks. This type of fluid motion gives rise to additional hydrodynamic loads on the walls of the tank. This paper is devoted to mathematical modeling of impact on the walls of the tank liquid membrane-type LNG carrier after impact with an ice barrier. Today, there are two ways to determine the hydrodynamic loads. The first method is semi-empirical and described in the Rules of classification and construction of LNG (2004). It is based on the hydrostatic law and the method of determining the acceleration motion of the vessel which, unfortunately, can not correctly describe the arising sloshing loads. The second method is based on the numerical solution of the Navier-Stokes equations or averaged Navier-Stokes equations. Such method for determining hydrodynamic loads requires huge computational power, however, it better reproduces the flow pattern and stresses on the walls of the LNG tank carrier. In the present work the second method is used and free surface is described by Volume-Of-Fluid method (VoF). One of the important problem is the prediction of the ship motion after impact with an ice barrier. In the present work the problem of jamming of the ship hull in the heavy ice conditions is solved, that allowed to estimate the parameters of the ship stopping. The simulation of the liquid gas flow in the prismatic membrane-type LNG tank after impact with ice barrier is presented. Calculations were made using open source code OpenFOAM. There are several variants of impact interaction of LNG with an ice barrier are investigated: the initial speeds of 4, 6 and 8 knots, and at three different fillings of the tank 10%, 70% and 98%.