Investigation of non-Newtonian fluid effects during transient flows in a pipeline

Ali Majd, Ahmad Ahmadi, Alireza Keramat

Research output: Journal article publicationJournal articleAcademic researchpeer-review

9 Citations (Scopus)


A sudden change in the flow rate brings about significant pressure oscillations in the piping system, known as water hammer (fluid hammer). Unsteady flow of a non-Newtonian fluid due to instantaneous valve closure is studied. Power law and Cross models are used to simulate non-Newtonian effects. Firstly, the appropriate governing equations are derived and then, they are solved by a numerical approach. A fourth-order Runge-Kutta scheme is used for the time integration, and the central difference scheme is employed for the spatial derivatives discretization. To verify the proposed mathematical model and numerical solution, a comparison with corresponding experimental results from the literature are made. The results reveal a remarkable deviation in pressure history and velocity profile with respect to the water hammer in Newtonian fluids. The significance of the non-Newtonian fluid behaviour is manifested in terms of the drag reduction and line packing effect observed in the pressure history results. A detailed discussion regarding the fluid viscosity and its shear-stress diagrams are also included.

Original languageEnglish
Pages (from-to)105-115
Number of pages11
JournalStrojniski Vestnik/Journal of Mechanical Engineering
Issue number2
Publication statusPublished - 2016
Externally publishedYes


  • Generalized Newtonian Fluid
  • Shear Thinning Fluids
  • Transient Pipe Flow

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering


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