On the non-linear forces acting on a floating spar platform in ocean waves

The exploitation of hydrocarbon reservoirs under the seabed in very deep wa ter requires the use of innovative floating platform configurations. The hy drodynamic interaction of such platforms with ocean waves and the understan ding and quantification of the non-linear components of these interactions have been a subject of continuing research. This paper examines these non-l inear interaction components for a specific very deep draft spar platform t ype that is increasingly being used in the oceans. It investigates a formul ation for two non-linear force components - called the axial divergence for ce and the centrifugal force. The latter is invariably neglected in convent ional analyses but is shown in this paper to actually be of significant imp ortance. Non-linear equations for wave loading and motion are developed and solved, and the results are used to demonstrate the significance of the ab ove terms. A limited comparison with experimental data is also presented. ( C) 2001 Elsevier Science Ltd. All rights reserved.