Hydrodynamic coefficients of a simplified floating system of gravity cage in waves

• Published in: Journal of Zhejiang University. A. Science 2008-05, Vol.9 (5), p.654-663
• Main Authors: Wu, Chang-wen, Gui, Fu-kun, Li, Yu-cheng, Fang, Wei-huan
• Format: Article
• Language: English
• Subjects: Civil Engineering; Classical and Continuum Physics; Engineering; Industrial Chemistry/Chemical Engineering; Mechanical Engineering; 流体震动; 浮动系统; 重力罩
• ISSN: 1673-565X; 1862-1775
• DOI: 10.1631/jzus.A0720016

Numerical simulation and experimental tests were carried out to examine the hydrodynamic behaviors of a double-column floating system of gravity cage under wave conditions. A floating system of gravity cage can be treated as a small-sized floating structure when compared with the wavelengths. The main problem in calculating the wave loads on the small-sized floating structure is to obtain the reasonable force coefficients, which may differ from a submerged structure. In this paper, the floating system of gravity cage is simplified to a 2D problem, where the floating system is set symmetrically under wave conditions. The motion equations were deduced under wave conditions and a specific method was proposed to resolve the problem of wave forces acting on a small-sized floating system of gravity cage at water surface. Results of the numerical method were compared with those from model tests and the hydrodynamic coefficients Cn and Cr were studied. It is found that Cn ranges from 0.6 to 1.0 while Cr is between 0.4 and 0.6 in this study. The results are useful for research on the hydrodynamic behavior of the deep-water gravity sea cages.