Author(s): Mariana Simao; Jesus Mora; H. M. Ramos
Linked Author(s): Jesús Mora Rodríguez
Keywords: FSI; Transient phenomena; Structure responses; Stress-strain relations
Abstract: The phenomenon of pipe movement related to unsteady fluid motion is termed fluid-structure interaction (FSI). It consists on the transfer of momentum and forces between piping and the contained liquid during dynamic flow conditions, manifested by pipe vibration and deformation associated to perturbations in velocity and pressure of the liquid. In a simple way, the effects caused by the fluid in the structure (axial and radial deformation, axial and torsional motion) affect the fluid pressure and velocity. The more severe deformations, faster the crack propagation becomes, causing a more expensive maintenance and a higher risk of operation. In addition, water-hammer occurs when the kinetic energy of a fluid is converted into elastic energy. But only rapid changes of the flow velocity will produce this effect, such as the sudden closure of a valve or the sudden failure or tripping of a pump. Due to the inertia of the fluid, the flow velocity of the liquid column as a whole is no longer capable of instantaneously adjusting to a new steady state condition. The fluid is disturbed and the pipe is deformed, with pressure transients accompanying the deformation process. FSI deals herein with the transfer of momentum and forces between a pipeline and its contained fluid, using different approaches to capture the transient phenomena. The governing equations and constitutive relations of fluid flow are coupled to stress-strain relations.
Year: 2014