Offshore Technology Research Center


OTRC Project Summary

Project Title:

Dynamic Analysis of Multiple-Body Floating Platforms Coupled with Mooring Lines and Risers

Prinicipal Investigators:

M. H. Kim and C. H. Kim


Minerals Management Service and Industry Consortium

Completion Date:

May, 2003

Final Report ID#

A132(Click to view final report abstract)

The main objective of this research is to develop a numerical program to analyze the hydrodynamic interaction responses of multiple bodies, mooring lines and risers based on the hull/mooring/riser coupled dynamic program called WINPOST-FPSO(Arcandra, 2001), using the hydrodynamic coefficients calculated by WAMIT (Lee, 1999) considering the interaction effects of the multiple-body.

The first stage consists of the evaluation and interpretation of the hydrodynamic interaction analysis results with WAMIT and the preparation of the wind and current force data (OCIMF, 1994) for performing the coupled dynamic analysis program newly developed (WINPOST-MULT) for the ship-shaped multiple-body system (FPSO, LNG carrier etc.). The interpretation program (WAMPOST-MULT) of the WAMIT results will be made for the preparing the properly formatted data for WINPOST-MULTI. For the wind and current forces, a modification in some parts of the original program (WINPOST-FPSO) will be needed.

In the second stage of this research, the original program (WINPOST-FPSO) will be developed to be able to perform the hull/mooring/riser coupled dynamic analysis for general multiple floating bodies. In the new program, it will be considered that the multiple bodies can be laid in any relative position to the open sea. The wave heading angle will be considered separately for each body at every small degree of angle and the relative angles between multiple bodies will be considered at every span in the same manner as for the wave heading angle.

The third stage is to prove the validity of the newly developed program through carrying out the numerical simulation after the proper models are selected. Buchner’s model (2001) and Choi’s model (2002) may be used for a comparative study about the results to be obtained from WINPOST-MULT. The former has the characteristics to deal with the close proximity problem of a side-by-side off-loading system. The latter took two, same sized vessels of an FPSO and a shuttle tanker to tackle the problems of both cases of the side-by-side system and the tandem system, and used the higher-order boundary element method (HOBEM) while the constant panel method(CPM) was used in WAMIT. The coupled dynamic analysis scheme adopted in the program WINPOST-MULT will be proved as the robust tool for analyzing the interaction problem of the multiple-body floating structure.

Related Publications: M.H. Kim and Y.B. Kim, “Hull/mooring/riser coupled dynamic analysis of a tanker-based turret-moored FPSO in deep water” Proc. 12th International Offshore and Polar Engineering Conference, Kita Kyushu, 2002

M.H. Kim, Y.B. Kim, R. Mercier, E.G. Ward, “Hull/mooring/riser coupled dynamic analysis of a turret-moored FPSO compared with OTRC experiment”, International Symposium on Deepwater Mooring Systems 2003, Houston.

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