Axial annular flow of plastic fluids: Dead zones and plug-free flow

Peter O. Brunn, Basim Abu-Jdayil

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


In axial annular flow, the shear stress decreases from its value τ(κR) at the inner cylinder to 0 at r = λR and increases from then on to τ(R) at the outer cylinder. For plastic fluids with a yield stress τc, λ will be such that flow commences when τ(κR) = τ(R) = τc. For fluids with position-dependent yield stresses (electro- and magnetorheological fluids are examples), the situation is more complex. While it is possible that yielding and flow occur everywhere, it is also possible that flow occurs only in parts of the fluid-filled space, and a dead zone (region in which the fluid is at rest) close to one of the walls exists. In that case, the fluid will flow no matter how small the applied pressure difference P = Δp/L is. If P is large enough, the dead zone ceases to exist and flow without any plug is possible. The fluid flows as if no yield stress exists.

Original languageEnglish
Pages (from-to)449-454
Number of pages6
JournalRheologica Acta
Issue number4
Publication statusPublished - Mar 2007


  • Axial annular flow
  • Dead zones
  • ERFs
  • MRFs
  • Non-Newtonian fluids
  • Plastic fluids
  • Plug-free flow

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics


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