On the Onsetof Thermal Instability in a Low Prandtl Number Nanofluid Layer in a Porous Medium

• Published in: Journal of Applied Fluid Mechanics Vol. 8; no. 2; pp. 265 - 272
• Main Authors: Chand, R, Rana, G C, Hussein, A K
• Format: Journal Article
• Language: English
• Published: Isfahan Isfahan University of Technology 01-04-2015
• Subjects: Brownian motion; Convection; Darcy number; Diffusivity; Free boundaries; Galerkin method; Grashof number; Lewis numbers; Low Prandtl- number; Mathematical models; Motion stability; Nanofluid; Nanofluids; Nanostructure; Porous media; Porous medium; Prandtl number; Stability analysis; Thermal energy; Thermal instability; Thermophoresis
• ISSN: 1735-3572; 1735-3645
• DOI: 10.18869/acadpub.jafm.67.221.22830

Thermal instability in a low Prandtl number nanofluid in a porous medium is investigated by using Galerkin weighted residuals method for free-free boundaries. For porous medium, Brinkman-Darcy modelis applied. The model used for the nanofluid describes the effects of Brownian motion and thermophoresis. Linear stability theory based upon normal mode analysis is employed to find the expression for stationary and oscillatory convection. The effects of Prandtl- number, Darcy number, Lewis number and modified diffusivity ratio on the stationary convection are investigated both analytically and graphically. The results indicated that the Prandtl and Darcy numbers have a destabilizing effect while the Lewis number and modified diffusivity ratio have a stabilizing effect for the stationary convection.