Variable viscosity effects on the vortex instability of free convection boundary layer flow over a horizontal surface in a porous medium

Jiin-Yuh Jang, Jin Sheng Leu

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13 Citations (Scopus)

Abstract

The role of temperature-dependent viscosity is studied in the flow and vortex instability of a heated horizontal free convection boundary layer flow in a saturated porous medium. For an isothermal surface, similarity solutions are found to exist for viscosity variation expressed as a general function of temperature. For exponential variation of viscosity with temperature, the numerical results for Nusselt number, critical Rayleigh number and associated wave number at the onset of vortex instability are presented over a wide range of wall to ambient viscosity ratio parameters. It is found that the variable viscosity effect enhances the heat transfer rate and destabilizes the flow for liquid heating, while the opposite trend is true for gas heating.

Original languageEnglish
Pages (from-to)1287-1294
Number of pages8
JournalInternational Journal of Heat and Mass Transfer
Volume36
Issue number5
DOIs
Publication statusPublished - 1993 Jan 1

Fingerprint

boundary layer flow
Boundary layer flow
Natural convection
free convection
Porous materials
Vortex flow
vortices
Viscosity
viscosity
Gas heating
Rayleigh number
Nusselt number
Temperature
temperature
heat transfer
Heat transfer
trends
Heating
heating
Liquids

All Science Journal Classification (ASJC) codes

  • Fluid Flow and Transfer Processes
  • Energy(all)
  • Mechanical Engineering
  • Engineering(all)

Cite this

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abstract = "The role of temperature-dependent viscosity is studied in the flow and vortex instability of a heated horizontal free convection boundary layer flow in a saturated porous medium. For an isothermal surface, similarity solutions are found to exist for viscosity variation expressed as a general function of temperature. For exponential variation of viscosity with temperature, the numerical results for Nusselt number, critical Rayleigh number and associated wave number at the onset of vortex instability are presented over a wide range of wall to ambient viscosity ratio parameters. It is found that the variable viscosity effect enhances the heat transfer rate and destabilizes the flow for liquid heating, while the opposite trend is true for gas heating.",
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AU - Leu, Jin Sheng

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N2 - The role of temperature-dependent viscosity is studied in the flow and vortex instability of a heated horizontal free convection boundary layer flow in a saturated porous medium. For an isothermal surface, similarity solutions are found to exist for viscosity variation expressed as a general function of temperature. For exponential variation of viscosity with temperature, the numerical results for Nusselt number, critical Rayleigh number and associated wave number at the onset of vortex instability are presented over a wide range of wall to ambient viscosity ratio parameters. It is found that the variable viscosity effect enhances the heat transfer rate and destabilizes the flow for liquid heating, while the opposite trend is true for gas heating.

AB - The role of temperature-dependent viscosity is studied in the flow and vortex instability of a heated horizontal free convection boundary layer flow in a saturated porous medium. For an isothermal surface, similarity solutions are found to exist for viscosity variation expressed as a general function of temperature. For exponential variation of viscosity with temperature, the numerical results for Nusselt number, critical Rayleigh number and associated wave number at the onset of vortex instability are presented over a wide range of wall to ambient viscosity ratio parameters. It is found that the variable viscosity effect enhances the heat transfer rate and destabilizes the flow for liquid heating, while the opposite trend is true for gas heating.

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