Nonlinear dynamics of deep water subsea lifting operations considering KC-dependent hydrodynamic coefficients

OCEAN ENGINEERING

卷:233

Article

Tommasini, Rodrigo Batista¹  Hill, Thomas L.²  Macdonald, John H. G.³  Pavanello, Renato¹  Carvalho, Leonardo de Oliveira⁴ 

[1] Univ Estadual Campinas, Dept Computat Mech, R Mendeleyev 200, BR-13083860 Campinas, SP, Brazil

[2] Univ Bristol, Dept Mech Engn, Queens Bldg Univ Walk, Bristol BS8 1TR, Avon, England

[3] Univ Bristol, Dept Civil Engn, Queens Bldg Univ Walk, Bristol BS8 1TR, Avon, England

[4] Petrobras SA, Res Ctr, Subsea Equipment Technol, Rua Horacio Macedo 950, BR-21941590 Rio De Janeiro, Brazil

关键词: Marine operations;    Subsea structure installation;    Hydrodynamic coefficients;    Keulegan-Carpenter number;    Harmonic balance method;    Cable forces;   

DOI  :  10.1016/j.oceaneng.2021.109172

来源: Elsevier

【 摘 要 】

The dynamics of deep water subsea lifting operations considering hydrodynamic coefficients that depend on the Keulegan-Carpenter (KC) number are analysed in this study. Firstly, experimental data from the literature is presented for a typical subsea manifold, relating the added mass and drag coefficients to the amplitude of oscillation, represented by the KC number. Then, the nonlinear non-dimensional equation of motion, that considers the variable hydrodynamic coefficients, is presented. The solution of this equation is obtained via the harmonic balance method and by iterative time domain integration, and the results are compared to those of a conventional model with constant hydrodynamic coefficients. The results obtained via the harmonic balance method are considered almost as accurate as from the time domain integration, but require significantly less computational effort. Also, it is shown that the amplitude-dependent model predicts variations in the natural frequency and damping of the system as a function of the amplitude of the response of the payload. This results in significant differences in the maximum cable tension and the payload depth at which it occurs, compared with the constant hydrodynamic coefficient model. Hence this shows the importance of considering variable hydrodynamic coefficients when analysing subsea lifting systems.

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