Thesis
Numerical simulation of green water and resulting loads
- Creator
- Rights statement
- Awarding institution
- University of Strathclyde
- Date of award
- 2012
- Thesis identifier
- T13314
- Qualification Level
- Qualification Name
- Department, School or Faculty
- Abstract
- The green water problem has been noted many years ago in the field of ship and marine engineering since it may have severe consequences on the ship structure. When green water incident happens, the water on the deck will hit even destroy the structures on deck. Especially in recent years, it occurs frequently and leads to many accidents related to deck bow and deck superstructures' damage of Floating Production Storage Offloading (FPSO). Therefore, the green water problem has become one of the important areas of research internationally. Green water is one of the strongly nonlinear ship-wave interaction problems and it is very difficult to solve mathematically. The physical phenomena of the green water occurrence are very complicated. The past investigations can only describe the phenomena to some extent, cannot give a reasonable explanation for the mechanism of green water and cannot be used in engineering practice. At present, with the development of high-speed computers and advances in computational fluid dynamics, numerical simulations are carried out for forecasting and analysing nonlinear fluid motions and resulting loads as well as physical experiments. Therefore, taking full advantages of advances in numerical modelling and combining model tests with numerical modeling to solve green water problem is a promising research area. A comprehensive review of the recent research investigations and progress made on green water problem is carried out in the present thesis. Green water flow and its impact load on the deck structure for a stationary FPSO and a moving FPSO with heave and pitch motions are investigated by a 2-D numerical simulation method. The simulations are carried out using a commercial software ANSYS FLUENT, to obtain an FPSO motions based on the potential flow theory and realized by dynamic mesh method. The green water flow behaviour and the resulting impact loads on the deck structure are calculated and analyzed for both fixed and moving FPSO. Numerical results of fixed FPSO agreed well with the corresponding experimental ones, and the moving FPSO's results showed that ship motions have great influence on green water phenomenon. Therefore, the method developed in this study can be applied to predict the impact forces on stationary structures in waves due to green water and conduct initial research on green water problem for moving FPSOs. It also can be regarded as a good engineering approach to evaluate the green water effects. Meanwhile, it can be used for the optimization of ship lines, especially forward lines and structural design of the deck structure. It can also help to take measures to avoid the possible damages due to green water. Key words: green water, CFD, potential flow theory, numerical wave tank, ship motion, dynamic mesh
- Resource Type
- DOI
- Date Created
- 2012
- Former identifier
- 967027
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