Wave drift damping acting on multiple circular cylinders (model tests)

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:182721

Kinoshita, Takeshi; Sunahara, Shunji; Bao, W ^[1]

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1. Univ. of Tokyo (Japan). Inst. of Industrial Science

The wave drift damping for the slow drift motion of a four-column platform is experimentally investigated. The estimation of damping force of the slow drift motion of moored floating structures in ocean waves, is one of the most important topics. Bao et al. calculated an interaction of multiple circular cylinders based on the potential flow theory, and showed that the wave drift damping is significantly influenced by the interaction between cylinders. This calculation method assumes that the slow drift motion is approximately replaced by steady current, that is, structures on slow drift motion are supposed to be equivalent to ones in both regular waves and slow current. To validate semi-analytical solutions of Bao et al., experiments were carried out. At first, added resistance due to waves acting on a structure composed of multiple (four) vertical circular cylinders fixed to a slowly moving carriage, was measured in regular waves. Next, the added resistance of the structure moored by linear spring to the slowly moving carriage were measured in regular waves. Furthermore, to validate the assumption that the slow drift motion is replaced by steady current, free decay tests in still water and in regular waves were compared with the simulation of the slow drift motion using the wave drift damping coefficient obtained by the added resistance tests.

• OSTI ID: 182721
• Report Number(s): CONF-950695--; ISBN 0-7918-1306-1
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
CALCULATION METHODS
DAMPING
MATHEMATICAL MODELS
OFFSHORE PLATFORMS
RESPONSE FUNCTIONS
WATER WAVES
WAVE FORCES