Effect of cubic temperature gradient on onset of thermal convection in a micropolar fluid

Thermal convection with shear flow has received widespread attention due to its importance in geophysical flows as well as several technological applications, such as heat exchangers and chemical vapour deposition. The thesis deals with two types of thermal convection in a fluid layer that is Raylei...

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Main Author: Mohd Isa, Nurul Afiqah
Format: Thesis
Language:English
Published: 2018
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Online Access:http://psasir.upm.edu.my/id/eprint/76540/1/FS%202018%2041%20-%20IR.pdf
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spelling my-upm-ir.765402020-01-30T06:43:59Z Effect of cubic temperature gradient on onset of thermal convection in a micropolar fluid 2018-04 Mohd Isa, Nurul Afiqah Thermal convection with shear flow has received widespread attention due to its importance in geophysical flows as well as several technological applications, such as heat exchangers and chemical vapour deposition. The thesis deals with two types of thermal convection in a fluid layer that is Rayleigh Benard convection (driven by buoyancy) and Marangoni convection (driven by surface tension). The Rayleigh-Benard and Marangoni stability problem for a fluid bound by bottom and top wall which are heated and cooled, respectively are studied numerically. The fluid layer with various boundary conditions at the different lower and upper boundary are investigated theoretically based on linear stability theory. The various boundary conditions are assumed for lower and upper boundaries to be free isothermal and free isothermal (FIFI), free isothermal and free adiabatic (FIFA), free isothermal and rigid adiabatic (FIRA), rigid isothermal and free isothermal (RIFI), rigid isothermal and free adiabatic (RIFA), and rigid isothermal and rigid adiabatic (RIRA). The effect of cubic temperature gradient, internal heat generation, feedback control, and electric field on the onset of Rayleigh-Bénard and Marangoni convection in an Eringen’s micropolar fluid has been examined. Three types of non-uniform basic temperature gradients which are linear, cubic 1 and cubic 2 are considered. The single-term Galerkin method is applied to obtain the eigenvalue for FIFI, FIFA, FIRA, RIFI, RIFA, and RIRA boundary combination. Closed form analytical solutions, of the full governing equations, are derived and the governing parameters of the problem are the thermal critical Rayleigh number, the critical Marangoni number, couple stress, coupling, and micropolar heat conduction, on the onset of convection has been analysed. It is found that cubic 1 is the most stabilizing temperature gradient and linear temperature gradient is the most destabilizing temperature gradient. Thermal conductivity Rayleigh-Bénard convection Fluid mechanics 2018-04 Thesis http://psasir.upm.edu.my/id/eprint/76540/ http://psasir.upm.edu.my/id/eprint/76540/1/FS%202018%2041%20-%20IR.pdf text en public masters Universiti Putra Malaysia Thermal conductivity Rayleigh-Bénard convection Fluid mechanics
institution Universiti Putra Malaysia
collection PSAS Institutional Repository
language English
topic Thermal conductivity
Rayleigh-Bénard convection
Fluid mechanics
spellingShingle Thermal conductivity
Rayleigh-Bénard convection
Fluid mechanics
Mohd Isa, Nurul Afiqah
Effect of cubic temperature gradient on onset of thermal convection in a micropolar fluid
description Thermal convection with shear flow has received widespread attention due to its importance in geophysical flows as well as several technological applications, such as heat exchangers and chemical vapour deposition. The thesis deals with two types of thermal convection in a fluid layer that is Rayleigh Benard convection (driven by buoyancy) and Marangoni convection (driven by surface tension). The Rayleigh-Benard and Marangoni stability problem for a fluid bound by bottom and top wall which are heated and cooled, respectively are studied numerically. The fluid layer with various boundary conditions at the different lower and upper boundary are investigated theoretically based on linear stability theory. The various boundary conditions are assumed for lower and upper boundaries to be free isothermal and free isothermal (FIFI), free isothermal and free adiabatic (FIFA), free isothermal and rigid adiabatic (FIRA), rigid isothermal and free isothermal (RIFI), rigid isothermal and free adiabatic (RIFA), and rigid isothermal and rigid adiabatic (RIRA). The effect of cubic temperature gradient, internal heat generation, feedback control, and electric field on the onset of Rayleigh-Bénard and Marangoni convection in an Eringen’s micropolar fluid has been examined. Three types of non-uniform basic temperature gradients which are linear, cubic 1 and cubic 2 are considered. The single-term Galerkin method is applied to obtain the eigenvalue for FIFI, FIFA, FIRA, RIFI, RIFA, and RIRA boundary combination. Closed form analytical solutions, of the full governing equations, are derived and the governing parameters of the problem are the thermal critical Rayleigh number, the critical Marangoni number, couple stress, coupling, and micropolar heat conduction, on the onset of convection has been analysed. It is found that cubic 1 is the most stabilizing temperature gradient and linear temperature gradient is the most destabilizing temperature gradient.
format Thesis
qualification_level Master's degree
author Mohd Isa, Nurul Afiqah
author_facet Mohd Isa, Nurul Afiqah
author_sort Mohd Isa, Nurul Afiqah
title Effect of cubic temperature gradient on onset of thermal convection in a micropolar fluid
title_short Effect of cubic temperature gradient on onset of thermal convection in a micropolar fluid
title_full Effect of cubic temperature gradient on onset of thermal convection in a micropolar fluid
title_fullStr Effect of cubic temperature gradient on onset of thermal convection in a micropolar fluid
title_full_unstemmed Effect of cubic temperature gradient on onset of thermal convection in a micropolar fluid
title_sort effect of cubic temperature gradient on onset of thermal convection in a micropolar fluid
granting_institution Universiti Putra Malaysia
publishDate 2018
url http://psasir.upm.edu.my/id/eprint/76540/1/FS%202018%2041%20-%20IR.pdf
_version_ 1747813169598824448