Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320855
Title: The stability properties of some rheological flows
Author: Demir, Huseyin
ISNI:       0000 0001 3421 8399
Awarding Body: University of Glamorgan
Current Institution: University of South Wales
Date of Award: 1996
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Abstract:
The stability of wall driven and thermally driven cavity flow is investigated for a wide range of viscous and viscoelastic fluids. The effect of inertia, elasticity, temperature gradients, viscous heating and Biot boundary conditions are of particular interest. Both destabilisation and bifurcation phenomenon are found. For Newtonian constant viscosity flow the instabilities are characterised by a critical Reynolds number which represents the ratio of inertial forces to viscous forces, and instability occurs when the inertial forces become large. For non-Newtonian viscoelastic fluids the instability is characterised by a critical Weissenberg number, which represents the ratio of elastic forces to viscous forces, and instability also occurs when elastic forces dominate the viscous forces. For thermally driven flow the instability is characterised by a critical Rayleigh number, which represents the ratio of temperature gradient to viscosity, and instability occurs when the Rayleigh number become large. In this case the instability is also characterised by both Eckert and Biot number. The work has relevance to thermal convection and mixing processes which occur in the viscous and viscoelastic fluid within the Earth's mantle. Three-dimensional steady and transient flow in a cylindrical cavity and three dimensional steady flow in a spherical cavity, are also considered for both viscous and viscoelastic fluids. Instabilities in these three-dimensional flow depend on the same parameters as the flow in square cavity.
Supervisor: Williams, R. W. ; Knight, D. G. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.320855  DOI: Not available
Keywords: Computational fluid dynamics
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