STABILITY OF NANOFLUID FLOW IN A VERTICAL POROUS CHANNEL

Mixed convection of a nanofluid saturated porous medium in a vertical channel is investigated numerically by using the spectral collocation method. The Darcy-Brinkman models are employed for the porous medium. Also, the model used for nanofluid incorporates the effects of Brownian motion and thermophoresis. Linear stability theory is employed to express the modified Grashof number as an implicit form of streamwise wavenumber based on the normal mode analysis. The neutral stability curves for the effects of Reynolds number, modified concentration Grashof number, porosity, Lewis number, Bodenstein number, modified diffusivity ratio, and modified particle density increment are shown graphically for the least stable mode. The results indicated that the Reynolds number and Bodenstein number have a destabilizing effect while modified concentration Grashof number, porosity, and Lewis number have a stabilizing effect, whereas modified diffusivity ratio and modified particle density increment have no significant effect for the least stable mode. Also, a neutral stability curve has been drawn for spanwise wavenumber, showing that it has a stabilizing effect for nanofluid in a vertical channel.