ON THE ONSET OF RAYLEIGH-BENARD CONVECTION IN A LAYER OF NANOFLUID IN HYDROMAGNETICS

Rayleigh-Benard convection in a horizontal layer of nanofluid in the presence of uniform vertical magnetic field is investigated by using Galerkin weighted residuals method. 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 expressions for Rayleigh number and critical Rayleigh number. The boundaries are considered to be free-free, rigid-rigid and rigid-free. The influence of magnetic field on the stability is investigated and it is found that magnetic field stabilizes the fluid layer. It is also observed that the system is more stable in the case of rigid-rigid boundaries and least stable in case of free-free boundaries. The expression for Rayleigh number for oscillatory convection has also been derived for free-free boundaries.