Responses of a spar platform in random waves and currents (experiment vs. theory)

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

OSTI ID:260402

Ran, Z; Kim, M H; Niedzwecki, J M; Johnson, R P ^[1]

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1. Texas A and M Univ., College Station, TX (United States)

In this paper, the motion characteristics of this new platform concept in storm waves and currents are investigated. Recently, a number of oil companies formed a Joint Industry Project (JIP) for the experimental study of a spar in the three dimensional wave basin of the Offshore Technology Research Center (OTRC) located at Texas A and M University. A series of experiments were conducted for various wave and current conditions with the 1:55 scale model of a slack-moored floating spar whose particulars are summarized. Contrary to its name, the present spar has large (40-m) diameter which is about 1/5 of its draft. In parallel with this kind of experimental program, the authors also developed a reliable numerical method to be able to predict the responses of the platform in random waves and current. From the JIP experiment, it was seen that the measured motion amplitudes of the spar in the survival condition were in general acceptable. The slowly-varying surge and pitch responses turned out to be much greater than wave-frequency responses. The numerical prediction agreed well with measured responses when the second-order diffraction method was used with viscous and wave-drift dampings. In this paper, the effects of wave directional spreading are not considered, and only the results for uni-directional waves with or without sheared currents are presented.

• OSTI ID: 260402
• Report Number(s): CONF-950604--; ISBN 1-880653-19-2
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
CALCULATION METHODS
COMPUTERIZED SIMULATION
DYNAMIC LOADS
FAILURE MODE ANALYSIS
FLUID-STRUCTURE INTERACTIONS
MATHEMATICAL MODELS
OFFSHORE PLATFORMS
PETROLEUM INDUSTRY
RESPONSE FUNCTIONS
STORMS
WATER WAVES
WAVE FORCES