J.C. Umavathi Effect of TimePeriodic Boundary Temperature on the Onset of Nanofluid Convection in a Layer of a Saturated Porous Medium
191 - 196
2013
7
1
International Journal of Mathematical, Computational, Physical, Electrical and Computer Engineering http://waset.org/publications/9996909
http://waset.org/publications/73
World Academy of Science, Engineering and Technology
The linear stability of nanofluid convection in a horizontal porous layer is examined theoretically when the walls of the porous layer are subjected to timeperiodic temperature modulation. The model used for the nanofluid incorporates the effects of Brownian motion and thermopherosis, while the Darcy model is used for the porous medium. The analysis revels that for a typical nanofluid (with large Lewis number) the prime effect of the nanofluids is via a buoyancy effect coupled with the conservation of nanoparticles. The contribution of nanoparticles to the thermal energy equation being a secondorder effect. It is found that the critical thermal Rayleigh number can be found reduced or decreased by a substantial amount, depending on whether the basic nanoparticle distribution is topheavy or bottomheavy. Oscillatory instability is possible in the case of a bottomheavy nanoparticle distribution, phase angle and frequency of modulation.
International Science Index 73, 2013