Weakly nonlinear analysis of Bénard–Marangoni instability in viscoelastic fluids
- 29 February 2000
- journal article
- Published by Elsevier BV in Journal of Non-Newtonian Fluid Mechanics
- Vol. 89 (1-2), 63-95
- https://doi.org/10.1016/s0377-0257(99)00031-2
Abstract
The coupled thermogravitational and thermocapillary instability in a thin fluid layer of a viscoelastic medium heated from below is investigated. A linear and a weakly nonlinear analysis are successively presented. The viscoelastic medium is modelled by means of a general rheological model including the lower convected, the upper convected, and the co-rotational Jeffreys models as particular cases. in comparison with previous analyses, two new dimensionless numbers are introduced, namely the so-called gravitational and rate of heating numbers instead of the classical Rayleigh and Marangoni numbers. The critical values for the temperature gradient, wave number and oscillation frequencies corresponding to the onset of convection are determined from a linear approach. After motion has set in, particular patterns are predicted taking the form of either rolls, or hexagon, or squares. By means of a nonlinear technique, restricted to steady situations, it is determined under which specific conditions one pattern is preferred. The influence of the constitutive equation, the Prandtl and the Blot numbers is examined and discussed in details. (C) 2000 Elsevier Science B.V. All rights reservedKeywords
This publication has 16 references indexed in Scilit:
- Bénard-Marangoni instability in a viscoelastic Jeffreys' fluid layerRheologica Acta, 1994
- Coupled buoyancy and thermocapillary convection in a viscoelastic Maxwell fluidJournal of Physics: Condensed Matter, 1993
- Instabilities in viscoelastic flowsRheologica Acta, 1992
- Linear instability in viscoelastic fluid convectionJournal of Physics: Condensed Matter, 1990
- Fluid Dynamics of Viscoelastic LiquidsApplied Mathematical Sciences, 1990
- Thermal convection in a viscoelastic liquidJournal of Non-Newtonian Fluid Mechanics, 1986
- Thermocapillary instability of a viscoelastic liquid layerActa Mechanica, 1985
- Stability of Fluid Motions IISpringer Tracts in Natural Philosophy, 1976
- Convective Stability of a General Viscoelastic Fluid Heated from BelowPhysics of Fluids, 1972
- On convection cells induced by surface tensionJournal of Fluid Mechanics, 1958