Estudo de VIM - Movimentos Induzidos por Vórtices em plataformas do tipo monocoluna: abordagem  numérico-experimental e impactos no sistema de amarração. / VIM study - Vortex Induced Motions in monocolumn type platforms: numeric-experimental approach and impact on mooring system.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2011

RESUMO

The vortex induced vibration VIV is a main subject studied in the offshore engineering, having its name adapted to VIM by the occurrence in Spar platforms in the Gulf of México. As the first monocolumn unit, the Sevan Piranema, was in Northeast Brazil in 2007, VIM occurrence in cylindrical units like this was questioned, having the mooring lines design dimensioned without this load. Firstly a detailed study about the works developed in this field was performed, and not being found enough publications about VIM in monocolumns, its characterization was aimed in terms of oscillation amplitude and period through model tests, due to the difficulty to obtain reliable results by means of analytical or numerical approaches. Later, with the objective of verifying the impact of VIM in extreme loads and, mainly, in fatigue damage, analyses with two different methods found in the literature were performed. The first consider the application of VIM as a motion in the numerical model, based on the experimental results, and the second applies the observed forces. For these studies the mooring system for a typical scenario was analyzed, under the wave, wind and current environmental force. At last, due to the importance observed from the results, there were discussed the relation of VIM with some external factors, like span wise relation, presence of waves and viscous damping, being presented for this last a comparison of the numerical model results with the experimental is presented.

ASSUNTO(S)

amarração análise de extremos e de vida útil ancoragem ensaios extreme analysis fadiga fatigue model testing monocolumn monocoluna mooring system vim vim viv viv

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