Numerical Modelling of Variability in Liquid Impacts

Liquefaction and subsequent transport in seagoing vessels yields a highly flexible method of transporting natural gas.
Sloshing of the liquefied natural gas (LNG) may however result in violent internal waves impacting the inside of partially filled tanks which are inside an LNG carrier, potentially compromising the integrity of the LNG tank.
Hence LNG tanks can only be designed to maximise the transport volume when the impact loads resulting from such impacts can reliably be predicted.
Repetition of wave impact experiments however shows highly variable perturbations at the wave crest just before impact, which greatly complicates the aforementioned prediction of impact loads.
In this thesis we develop and utilise state-of-the-art numerical simulation techniques with the aim of understanding the physical phenomena which underlie the variability apparent in liquid impacts.
In particular, we analyse and develop numerical methods for the propagation of waves, which respect essential physical principles such as the conservation of mass and momentum, while not requiring all of the physical details to be modelled as this would be computationally too expensive.
We find that our numerical model can reliably predict the shape of the perturbations on the wave crest before impact, and in particular we confirm numerically that the use of small scale experiments leads to an overprediction of the size of these deformations.
It follows that the numerical model is suitable for the prediction of variability in liquid impacts, and can therefore be used as a tool in the design of LNG tanks.