Nonplanar flow-induced vibrations of a cantilevered PIP structure system concurrently subjected to internal and cross flows
- 114 Downloads
Pipe-in-pipe (PIP) structures are widely used in offshore oil and gas pipelines to settle thermal insulation issues. A PIP structure system usually consists of two concentric pipes and one softer layer for thermal insulation consideration. The total response of the system is related to the dynamics of both pipes and the interactions between these two concentric pipes. In the current work, a theoretical model for flow-induced vibrations of a PIP structure system is proposed and analyzed in the presence of an internal axial flow and an external cross flow. The interactions between the two pipes are modeled by a linear distributed damper, a linear distributed spring and a nonlinear distributed spring along the pipe length. The unsteady hydrodynamic forces due to cross flow are modeled by two distributed van der Pol wake oscillators. The nonlinear partial differential equations for the two pipes and the wake are further discretized by the aid of Galerkin’s technique, resulting in a set of ordinary differential equations. These ordinary differential equations are further numerically solved by using a fourth-order Runge–Kutta integration algorithm. Phase portraits, bifurcation diagrams, an Argand diagram and oscillation shape diagrams are plotted, showing the existence of a lock-in phenomenon and figure-of-eight trajectory. The PIP system subjected to cross flow displays some interesting dynamical behaviors different from that of a single-pipe structure.
KeywordsCantilevered PIP structure Theoretical model Flow-induced vibration Cross flow Internal flow
The work was supported by the National Natural Science Foundation of China (Grant 11622216).
- 1.Yettou, E., Derradji-Aouat, A., Williams, C.: Fluid-Structure Interactions Modelling of PIP Riser Systems Operating in Ocean Environments. National Research Council Canada, Institute for Ocean Technology, St. John’s (2008)Google Scholar
- 2.Sun, J., Jukes P.: From installation to operation: a full-scale finite element modeling of deep-water PIP system. In: Third ISOPE International Deep-Ocean Technology Symposium. International Society of Offshore and Polar Engineers, Beijing, May 31–June 5 (2009)Google Scholar
- 3.Sun, J., Jukes, P., Eltaher, A.: Exploring the challenges of pipe-in-pipe (PIP) flowline installation in deepwater. In: Third ISOPE International Deep-Ocean Technology Symposium. International Society of Offshore and Polar Engineers, Beijing, June 28–July 1 (2009)Google Scholar
- 25.Yang, Z.M., Thorkildsen, F., Norland, K.: Vortex induced vibrations and fatigue assessment of pipe-in-pipe systems. In: Proceedings of the ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, Madrid, 17–22 June (2018)Google Scholar
- 26.Williams, D., Kenny, F.: Calculation of VIV fatigue of multi-pipe systems. In: ASME 2017 36th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, Trondheim, 25–30 June (2017)Google Scholar