Vortex-induced vibration experiments with a long semi-immersed flexible cylinder under tension modulation: Fourier transform and Hilbert-Huang spectral analyses

Autor(es)

Franzini, Guilherme R. ^{[1, 2, 3, 4]} ; Goncalves, Rodolfo T. ^[1] ; Pesce, Celso P. ^[4] ; Fujarra, Andre L. C. ^{[1, 4]} ; Mazzilli, Carlos E. N. ^[3] ; Meneghini, Julio R. ^[2] ; Mendes, Pedro ^[5]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Escola Politecn, TPN Numer Offshore Tank, BR-2231 Sao Paulo - Brazil

^[2] Univ Sao Paulo, Escola Politecn, NDF Fluids & Dynam Res Grp, BR-2231 Sao Paulo - Brazil

^[3] Univ Sao Paulo, Escola Politecn, LMC Lab Computat Mech, BR-2231 Sao Paulo - Brazil

^[4] Univ Sao Paulo, Escola Politecn, LMO Offshore Mech Lab, BR-2231 Sao Paulo - Brazil

^[5] Petrobras SA, Rio De Janeiro - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of the Brazilian Society of Mechanical Sciences and Engineering; v. 37, n. 2, p. 589-599, MAR 2015.
• Citações Web of Science: 4

Resumo

An experimental investigation of the vortex-induced vibration phenomenon on a long semi-immersed flexible cylinder in constant current profile were carried out at a recirculating water channel facility. The experiments are part of a comprehensive research project which aims a better understanding of non-linear riser dynamics. Vertical and prescribed monochromatic harmonic motions were imposed to the top with amplitude A(t)/L approximate to 1% causing eigenfrequencies modulations. The mass ratio parameter is m{*} approximate to 10, and the ratio between the total length L and the immersed length Lim is L/Lim approximate to 3.5. The Reynolds number Re range lies within the interval 10(3) < Re <10(4). Three values of motion frequency f(t) were imposed, being them f(t) : f(N,1) - 1:3, 1:2 and 1:1 where f(N,1) is the first eigenfrequency. The application of both the Fourier Transform and the Hilbert-Huang Transform allowed identifying subharmonic components and also frequency modulation aspects in the data. (AU)

• 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
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado