Electrohydrodynamic Instability in a Heat Generating Porous Layer Saturated by a Dielectric Nanofluid

In this paper, a theoretical investigation has been carried out to study the combined effect of AC electric field and temperature depended internal heat source on the onset of convection in a porous medium layer saturated by a dielectric nanofluid. The model used for nanofluid incorporates the combined effect of Brownian diffusion, thermophoresis and electrophoresis, while for porous medium Darcy model is employed. The flux of volume fraction of a nanoparticle with the effect of thermophoresis is taken to be zero on the boundaries and the eigenvalue problem is solved using the Galerkin method. Principle of exchange of stabilities is found to be valid and subcritical instability is ruled out. The results show that increase in the internal heat source parameter , AC electric Rayleigh-Darcy number , the Lewis number , the modified diffusivity ratio and the concentration Rayleigh-Darcy number are to hasten the onset of convection. The size of convection cells decreases with increasing the internal heat source parameter and the AC electric Rayleigh-Darcy number .

Keywords:

Electrohydrodynamic instability , Nanofluids , Internal heat source , Porous medium