The instability of non-Newtonian boundary-layer flows over rough rotating disks

A.A Alqarni, B. Alveroğlu, Paul Griffiths, S. J. Garrett

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

We are concerned with the local linear convective instability of the incompressible boundary-layer flows over rough rotating disks for non-Newtonian fluids. Using the Carreau model for a range of shear-thinning and shear-thickening fluids, we determine, for the first time, steady-flow profiles under the partial-slip model for surface roughness. The subsequent linear stability analyses of these flows (to disturbances stationary relative to the disk) indicate that isotropic and azimuthally-anisotropic (radial grooves) surface roughness leads to the stabilisation of both shear-thinning and -thickening fluids. This is evident in the behaviour of the critical Reynolds number and growth rates of both Type I (inviscid cross flow) and Type II (viscous streamline curvature) modes of instability. The underlying physical mechanisms are clarified using an integral energy equation.
Original languageEnglish
Article number104174
JournalJournal of Non-Newtonian Fluid Mechanics
Volume273
Early online date9 Oct 2019
DOIs
Publication statusPublished - Nov 2019

Keywords

  • Carreau fluid
  • Convective instability
  • Laminar boundary layer
  • Non-Newtonian

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering
  • Applied Mathematics

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