An experimental investigation on concomitant Vortex-Induced Vibration and axial top-motion excitation with a long flexible cylinder in vertical configuration

Autor(es)

Franzini, G. R. ^[1] ; Pesce, C. P. ^[1] ; Goncalves, R. T. ^{[1, 2]} ; Fujarra, A. L. C. ^{[3, 4]} ; Mendes, P. ^[5]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Escola Politecn, LMO Offshore Mech Lab, Sao Paulo - Brazil

^[2] Univ Tokyo, Sch Frontier Sci, Tokyo - Japan

^[3] Univ Fed Santa Catarina, Dept Mobil Engn, Florianopolis, SC - Brazil

^[4] Univ Sao Paulo, LMO, Sao Paulo - Brazil

^[5] Petrobras SA, Riser & Flowline Engn Syst, Rio De Janeiro - Brazil

• Tipo de documento: Artigo Científico
• Fonte: OCEAN ENGINEERING; v. 156, p. 596-612, MAY 15 2018.
• Citações Web of Science: 1

Resumo

An experimental investigation of concomitant Vortex-Induced Vibration (VIV) and top-motion excitation with a long and vertical flexible cylinder is presented. Underwater optical instrumentation allows to directly measure the cartesian coordinates of 43 targets placed along the model. Standard analyses, based on statistical evaluation of local displacement time-histories and on spectral analysis, are carried out. Additionally to the standard approach, modal decomposition is adopted, allowing to obtain modal-amplitude time-histories. It was found that the concomitant VIV and top-motion excitation significantly affects the flexible cylinder response when compared to the pure VIV tests. When the top-motion excitation has frequency twice the first natural frequency in still water (f(t) f(N,1) = 2 : 1), parametric instability of the first vibration mode occurs concomitant to VIV phenomenon. Such instability leads to a marked increase in the oscillation amplitudes for the whole range of towing speed tested. (AU)

• Processo FAPESP: 14/02043-1 - Comportamento de plataformas de petróleo sob a ação do fenômeno de VIM e incidência simultânea de ondas
• Beneficiário: Rodolfo Trentin Gonçalves
• Linha de fomento: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 13/09802-2 - Estudo do escoamento ao redor de cilindros inclinados e de baixa razão de aspecto com vistas ao movimento induzido pela emissão de vórtices (MIV) de plataformas flutuantes
• Beneficiário: Guilherme Rosa Franzini
• Linha de fomento: Bolsas no Brasil - Pós-Doutorado