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

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 literature is presented for a typical manifold, relating added mass and drag to amplitude oscillation, represented by KC number. Then, nonlinear non-dimensional equation motion, considers variable coefficients, presented. solution obtained via harmonic balance method iterative time domain integration, results compared those conventional model with constant coefficients. considered almost as accurate but require significantly less computational effort. Also, it shown amplitude-dependent predicts variations natural frequency damping system function response payload. This significant differences maximum cable tension payload depth at which occurs, coefficient model. Hence shows importance when analysing systems.