Centre for Offshore Foundation Systems

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Xiantao Zhang


Start date

May 2015

Submission date

May 2019

Xiantao Zhang

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Thesis

Numerical study of green water incidents for offshore structures under extreme waves

Summary

The open source CFD toolbox OpenFoamĀ® ,combined with a fully nonlinear wave generation and absorption utility, waves2Foam, is adopted to perform numerical simulation of green water.

The following key results are expected to be achieved: 1. to develop an effective and efficient numerical model of green water incidents; 2. investigations will be put on the velocity and pressure distribution of the multi-phase water-on-deck flow during the occurrence of green water to give an insight into the phenomenon; 3. to conduct a parametric study, such as the effects of wave parameters and main shape characteristics of ship on the water height and resultant impact force; 4. statistical properties of green water incidents will be addressed and empirical models of prediction of occurrence of green water incidents will be established; 5. to investigate the effects of green water on the global motion, such as the stability, of offshore structures.

Why my research is important

Green water is one of the strongly nonlinear wave-structure interaction problems and occurs when a ship, usually in harsh weather conditions, encounters waves that significantly exceed the freeboard and cause shipment of water on the deck. The large amount of shipped water leads to high impact forces that can damage deck equipment, plating, structures or cause cargo transporting on the deck. In order to maintain the operational stability and structural integrity of offshore structures, lots of efforts have been put on the following two aspects of green water phenomenon: the first one is the investigation into how and when green water occurs and the second one refers to researches dedicated to evaluate the flow characteristics and the resultant loading effects on the deck structure.

Funding

  • International Postgraduate Research Scholarships (IPRS), Australia Postgraduate Award (APA), Shell-UWA Offshore Engineering PhD Research Top-Up Scholarship