Thermal Impermanence of a couple stress visco-elastic Walter’s (modal B´) nanofluid layer through a porous medium

Thermal Impermanence of a couple stress visco-elastic Walter’s (modal B´) nanofluid layer through a porous medium is investigated for more realistic boundary conditions. By applying Perturbation method, Normal mode technique, the effects of the various physical parameters of the system namely Lewis number, modified diffusivity ratio, nano particle Rayleigh number and couple stress on the stationary convection have been investigated both analytically and graphically. The Lewis number, modified diffusivity ratio and nano particle Rayleigh number are found to have stabilizing effect, whereas couple stress has a destabilizing effect for stationary convection.