Fluid-structure interaction during water hammer in a pipeline with different performance mechanisms of viscoelastic supports

Abstract

The aim of this research is to model various types of viscoelastic supports and to investigate their effects on the fluid-structure interaction (FSI) during the water hammer in straight pipeline systems. Three performance mechanisms of viscoelastic supports are considered. The first is the viscoelastic supports with axial deformation, the second is viscoelastic supports with shear deformation and the third is the viscoelastic supports with both sliding and shear deformation mechanisms. The Poisson and junction coupling were taken into account as the main interacting mechanisms. The viscoelastic behavior of the pipe-wall and the supports was described by the generalized Kelvin-Voigt mechanical model. By providing boundary conditions for the different types of viscoelastic supports modeling at the valve location and along the pipe, the governing equations were solved using the full MOC method in the time domain. The results demonstrated that the use of viscoelastic supports with axial and shear deformation mechanisms are effective in the damping of the pressure head vibrations and reducing the displacement of the pipe-wall caused by FSI. The viscoelastic supports with the shear deformation mechanism exhibited better performance compared to those with the axial deformation mechanism. The results also showed that the behavior of viscoelastic supports with both sliding and shear mechanisms depended on the amount of frictional force in the supports. Using plates with an appropriate friction coefficient for the sliding viscoelastic supports caused a significant reduction in the amount of pressure head and displacement of the pipe-wall as well as considerable pressure head fluctuations damping compared to the performance of two other mechanisms of viscoelastic supports in a similar situation, especially in the elastic pipe.