Non-Newtonian flow instability in a channelwith a sudden expansion

Panagiotis Neofytou, Dimitris Drikakis

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The paper presents a numerical investigation of instabilities occurring in non-Newtonian flows through a sudden expansion. Three non-Newtonian models, used in the literature for simulating the rheological behaviour of blood, are employed, namely the Casson, Power-Law, and Quemada models. The computations reveal that similar to Newtonian flow through a suddenly expanded channel, an instability also occurs in non-Newtonian flows. The instability is manifested by a symmetry breaking of the flow separation. The onset of the instability depends on the specific parameters involved in each model's constitutive equation. The investigation encompasses a parametric study for each model, specifically the critical values at which transition from stable to unstable flow occurs. Due to the fact that for each of the Casson and Quemada models, two characteristic flow parameters exist, the relation between the critical values for each of these parameters is also examined.

Original languageEnglish
Pages (from-to)127-150
Number of pages24
JournalJournal of Non-Newtonian Fluid Mechanics
Issue number2-3
Publication statusPublished - 30 Apr 2003


  • Bifurcation phenomena
  • Blood flow
  • Non-Newtonian flow
  • Numerical simulation
  • Separated flow


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