Cristin-resultat-ID: 1271686
Sist endret: 31. mai 2017, 08:53
Resultat
Vitenskapelig Kapittel/Artikkel/Konferanseartikkel
2009

Viscous drift forces and responses on a semisubmersible platform in high waves - OMAE2009-79483

Bidragsytere:
  • Rolf Jarle Baarholm

Bok

Om resultatet

Vitenskapelig Kapittel/Artikkel/Konferanseartikkel
Publiseringsår: 2009
ISBN:
  • 9780791838440

Importkilder

SINTEF AS-ID: S12451

Beskrivelse Beskrivelse

Tittel

Viscous drift forces and responses on a semisubmersible platform in high waves - OMAE2009-79483

Sammendrag

In this paper the significance of viscous effects on a moored semisubmersible platform in various sea state conditions is explored. Experimental data from a 1:50 model scale tests in a 50m×80m wave basin are compared with numerical time domain simulations. Both regular and irregular waves are included, and some tests are also run with current. This paper presents results from a horizontally moored semisubmersible, where we focus on the hull hydrodynamics alone. The emphasis here is low frequency surge responses.Use of conventional potential theory shows large discrepancies when compared with experimental results in high sea states. For surge motion, they are believed to be due to viscous forces in the wave zone. Viscous forces and damping in the numerical model are included by the drag term of Morison’s equation using a total relative velocity approach, which is integrated up to the instantaneous free surface elevation. A common challenge is to choose a suitable Cd coefficient which provides for sufficient excitation force without introducing excessive motion damping. It is found that using a larger Cd coefficient in the wave zone gives larger excitation without influencing the total damping significantly. This way, applying the drag term of Morison’s equation can give results that compare well with measurements. Also, the coefficient is found to be lower in waves with current than in waves only.

Bidragsytere

Rolf Jarle Baarholm

  • Tilknyttet:
    Forfatter
    ved Skip og havkonstruksjoner ved SINTEF Ocean
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Resultatet er en del av Resultatet er en del av

Proceedings of the ASME 28th International Conference on Ocean, Offshore and Arctic Engineering - OMAE2009.

Ertekin, R. Cengiz; Riggs, H. Ronald. 2009, Vitenskapelig antologi/Konferanseserie
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