(94b) Fluid-Structure Interaction Modeling of a Subsea Jumper Pipe

Subsea jumper pipes carrying production flows from oil wells experience different types of fluctuating forces. These fluctuating forces can be categorized as internal or external. Internal forces are mainly caused by the multiphase flows passing through the pipe resulting in significant pressure fluctuations acting on the internal pipe walls. These internal fluctuating forces lead to what is known as flow-induced vibration (FIV). External fluctuating forces, on the other hand, are caused by sea currents, which create cyclic vortex-shedding at the rear  side of the structure. These shed vortices similarly cause pressure fluctuations on the external pipe wall resulting in what is known as vortex-induced vibration (VIV). VIV and FIV can interact and have a strong effect on the structure integrity; can cause resonance or fatigue,  which may lead to structure failure, losses in production, and devastating environmental effects. Thus, it is important to accurately predict FIV and VIV effects and their impact on the fatigue life during the design phase of any subsea jumper pipes. To this end, the Fluid-Structure Interaction (FSI) modeling directly solves for the transient displacement response of the jumper pipe due to FIV and VIV. With the displacement response time history, a fatigue analysis can then determine the life time of the jumper pipe subject to cyclic excitations from VIV and FIV.
This paper presents a multiphysics modeling methodology for investigating the fatigue life time of a subsea jumper pipe due to flow-induced vibration (FIV) and vortex-induced vibration (VIV). This modeling methodology consists of fluid-structure interaction (FSI) modeling of a subsea jumper pipe with both internal multiphase flow and external seawater current (FIV and VIV) and fatigue analysis.