Waterhammer modelling of viscoelastic pipes with a time-dependent Poisson's ratio

Alireza Keramat, Arash Ghaffarian Kolahi, Ahmad Ahmadi

Research output: Journal article publicationJournal articleAcademic researchpeer-review

37 Citations (Scopus)

Abstract

Poisson's ratio in viscoelastic materials is a function of time. However, recently developed waterhammer models of viscoelastic pipes consider it constant. This simplifying assumption avoids cumbersome calculations of double convolution integrals which appear if Poisson's ratio is time-dependent. The present research develops a mathematical model taking the time dependency of Poisson's ratio into account for linear viscoelastic pipes. Poisson's ratio is written in terms of relaxation function and bulk modulus which is assumed to be constant. The relaxation function is obtained from creep function given as the viscoelastic property data of pipe material. The results obtained from the present waterhammer model are compared with the experimental data for two different flow rates. The comparison reveals that with the application of the time-dependent Poisson's ratio and unsteady friction, the viscoelastic data of mechanical tests can directly be used for waterhammer analysis with less need for the calibration of the flow configuration. It was also shown that the creep curve calibrated based on the present model is closer to the actual creep curve than that calibrated based on previous models.

Original languageEnglish
Pages (from-to)164-178
Number of pages15
JournalJournal of Fluids and Structures
Volume43
DOIs
Publication statusPublished - Nov 2013
Externally publishedYes

Keywords

  • Method of characteristics
  • Poisson's ratio
  • Polyethylene
  • Viscoelastic pipe
  • Waterhammer

ASJC Scopus subject areas

  • Mechanical Engineering

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