Study of sloshing impact pressures using level set method

[Truncated abstract] Sloshing in a closed tank is a complicated phenomenon showing strong nonlinearity and randomness. A good understanding of the hydrodynamics of sloshing such as wave loads, wave propagation and breaking are important for the design of liquefied natural gas (LNG) carriers. This study provides a platform to assess sloshing loads by utilizing numerical and experimental approaches. In particular this thesis primarily concentrates on studying droplet impacts under different physical conditions. Sloshing experiments have been performed at the Hydrodynamics Laboratory facility, The University of Western Australia. In a series of experiments, it was found that a sampling frequency of 40 kHz was sufficient to capture impact pressure accurately. A general investigation has been conducted to record and visualize different types of impact pressure patterns along different fill levels. These experiments formed part of a bigger set of experiments performed as part of Western Australian Energy Research Alliance (WA: ERA) Sloshing research project supported by Chevron ETC. High impact pressures (about 100-120 kPa) were observed for jet flow and droplet impacts, therefore by studying the droplets, it is anticipated that the study can be generalised and applied to jet flow impacts. A detailed literature survey revealed that among the available numerical methods the level set method had the ability to implicitly model the interface with required accuracy in dealing with sharp interfaces. A computer code based on level set method has been developed to simulate droplet impacts. Lack of mass conservation, a major limitation of conventional level set method, was resolved by improving the reinitialization algorithm. Benchmark problems are solved to showcase the area preserving ability of the proposed improvement. The code has been validated comparing the numerical results with the published results.