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

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

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Non-Newtonian Flow
Rotating Disk
Shear Thinning
boundary layer flow
Boundary layer flow
Boundary Layer Flow
rotating disks
Rotating disks
Surface Roughness
Rough
shear thinning
Shear thinning
Partial Slip
Convective Instability
Energy Integral
Fluid
Cross-flow
Fluids
fluids
Non-Newtonian Fluid

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

Cite this

The instability of non-Newtonian boundary-layer flows over rough rotating disks. / Alqarni, A.A; Alveroğlu, B.; Griffiths, Paul; Garrett, S. J.

In: Journal of Non-Newtonian Fluid Mechanics, Vol. 273, 104174, 11.2019.

Research output: Contribution to journalArticle

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