On the dynamics of turret systems in deep water

• Published in: Applied ocean research 2003-02, Vol.25 (1), p.37-51
• Main Authors: Grotta Ragazzo, C., Tannuri, E.A.
• Format: Article
• Language: English
• Subjects: Applied fluid mechanics; Applied sciences; Buildings. Public works; Deep water; Dynamics; Exact sciences and technology; Fluid dynamics; Fundamental areas of phenomenology (including applications); Hydraulic constructions; Hydrodynamics, hydraulics, hydrostatics; Marine; Offshore structure (platforms, tanks, etc.); Physics; Turret system
• ISSN: 0141-1187; 1879-1549
• DOI: 10.1016/S0141-1187(03)00030-0

In the present paper the problem of slow dynamics (surge, sway, and yaw) of a tanker equipped with a turret system in deep water is considered. In this situation the mooring line damping dominates the overall damping related to surge and sway and attenuate these motions. The environmental input acts primarily on the yaw motion and the surge and sway response is mainly determined by the angle between the ship and the predominant environmental agents. Here, these ideas are formalized using the theory of center manifolds. The main result is an explicit equation for the yaw dynamics decoupled from the other degrees of freedom. This approach does not depend on any particular mathematical model on how the tanker interacts with the several environmental agents. Finally, numerical simulations are successfully used to compare the reduced and the full systems for various values of water depth and two different hydrodynamic models. The dynamical reduction presented here simplify the dynamical analysis of turret systems in deep water.