Untitled in english

Author(s)

Carlos Hakio Fucatu

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Escola Politécnica (EP/BC)
• Defense date: 2003-08-29

Examining board members

Kazuo Nishimoto; Isaias Quaresma Masetti; Julio Romano Meneghini; Celso Kazuyuki Morooka

• Advisor: Kazuo Nishimoto

Abstract

The ship based Floating Production Storage and Offloading system (FPSO) has been largely used in the recent offshore oil exploration. In most of the cases the oil stored in FPSO is offloaded to a shuttle ship that is connected by a hawser in tandem configuration. Although the tandem mooring is a common procedure in the offshore oil industry, there are few publications related to the theme. Among these, there is none concerned with the current forces interference caused by FPSO on the shuttle ship, here called shadow effect. It is well known that the dynamic behavior of a moored ship, in particular SPM system, is hardly affected by the environmental forces. Therefore, it is expected that the shadow effect on the hydrodynamic forces acting on the shuttle ship will cause great influence on its dynamic behavior, and consequently in the dynamics of whole FPSO-shuttle system. This phenomenon could be observed in experiments with single point moored shuttle ships with and without the FPSO in upstream position. Therefore, for the sake of reality, the shadow effect must be considered in analysis of dynamic behavior of two ships connected in tandem. Among the commercial simulators that analyze tandem systems there is none that considers the shadow effect, providing an analysis different from the real world. This thesis presents a study of the current shadow effect. The shadow effect model, based on the disturbed current field was developed and implemented in anumerical simulator named DYNASIM. The comparison between numerical results and experimental ones showed that the proposed model is effective. (AU)