Influence of heave plate geometry on the heave response of classic spars

Krish P. Thiagarajan, Alex Z. Ran, Indra Datta, Longbin Tao, John E. Halkyard

Research output: Chapter in Book/Report/Conference proceedingConference contribution book

28 Citations (Scopus)

Abstract

A production spar designed for West African (WA) offshore conditions must consider possible resonance with long period swell, which might result in large amplitude heave oscillations. Preliminary study of a classic spar with diameter of 39 m (128 ft) and draft 198 m (650 ft) for a WA application led the authors to believe that excessive heave response of 5.2 m (17 ft) may occur at the natural period of 28 seconds. This led the team to investigate the possibility of adding a heave plate (circular disk) at the base of the spar to control the response to within 3.1 m (10 ft), which is the limit set by a typical compensation system. Important design issues arose with regards to the geometry of the plate, i.e. diameter and thickness. Numerical simulations and model testing were used to identify the influence of a heave plate on the heave response of the spar. Heave response for various diameters and thickness were investigated. Comparison of added mass and damping values were found to be in reasonable agreement. Issues such as effect of a centerwell and moorings, plate cutouts for ease of transportation were also investigated. Discussion of the experimental results and comparison with numerical simulations are presented in this paper, and some recommendations are made on optimum heave plate geometry.

Original languageEnglish
Title of host publicationASME 2002 21st International Conference on Offshore Mechanics and Arctic Engineering
Place of PublicationNew York
PublisherAmerican Society of Mechanical Engineers(ASME)
Pages621-627
Number of pages7
ISBN (Print)0791836118
DOIs
Publication statusPublished - 23 Jun 2002
EventProceedings of the 21st International Conference on Offshore Mechanics and Arctic Engineering (OMAE) - Oslo, Norway
Duration: 23 Jun 200228 Jun 2002

Conference

ConferenceProceedings of the 21st International Conference on Offshore Mechanics and Arctic Engineering (OMAE)
Country/TerritoryNorway
CityOslo
Period23/06/0228/06/02

Keywords

  • geometry
  • spar platforms
  • coputer simulation
  • damping

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