The Smoothed Particle Hydrodynamics (SPH) method is applied to the problem of modeling sloshing in a two-dimensional system. The systems chosen are those specified in the document "Instructions for 1 st Sloshing Dynamics Symposium at ISOPE-2009 Conference". Two different tank configurations are considered with 2 fill ratios (20, 70%) and different oscillation amplitudes. Pressure signals are predicted at locations at which experimental measurements have been made, but not revealed, to contributing authors. SPH is seen to be able to predict the surface profiles and distinguish between the different flow cases. It is a natural technique for such coupled fluid-structure problems with large free surface deformations.
Sloshing in partially filled LNG tanks can arise under different wave conditions when loading and/or unloading LNG from a tanker ship, when tankers must disengage part way through offshore loading due to approaching adverse weather conditions or in FPSO's under normal operating conditions. Sloshing may resonate with the frequencies of wave-induced ship motions and may resonate with structural frequencies. This in turn can affect ship stability and, of particular importance here, can produce large loads on the internal walls of the tank, potentially leading to structural damage of tank membranes and insulation, leakage and, in the worst case scenario, tank rupture. Small-scale physical experiments can be undertaken with water or other fluids and then scaled up to full size to predict tank loadings under different wave conditions and fill levels. However it is highly desirable to have robust computational tools that provide accurate estimates of loadings under different conditions. Not only do computational methods allow a quick turn around for investigating different tank geometries, wave conditions and fill levels, it is also possible to apply the correct equations of state for liquid LNG - a task far more difficult to achieve in experimentation due to the difficulty in making measurement at very low temperatures as well as the significant safety issues when using liquid LNG.
