On the Dynamics and Stability of a Viscoelastic Pipe Conveying a Non-Newtonian Fluid

Flow induced vibration of pipeline and riser systems are strongly dependent on internal fluid flow parameters as well as the mechanical properties of the conveyance vessel. The effect of variability of flow parameters especially at elevated temperatures can lead to instability, buckling and bursting of these systems. In this paper, the effect of high temperature fluid transmission on the vibration and stability of an offshore viscoelastic pipeline conveying a non-Newtonian fluid is investigated analytically. By idealising the viscoelastic pipeline resting on the sea bed as a viscoelastic beam that is resting on an elastic continuum, a non-linear boundary value partial differential equation governing the fluid-structure-soil interaction mechanics is formulated. In particular, formal linearization of the governing partial differential equation, under slight perturbation of the internal fluid velocity and other flow variables revealed their impact, on the natural frequency and stability of the system which can then be computed for design analysis and applications.