Linear, Parabolic, and Inverted Parabolic Temperature Gradients Impact on Double-Diffusive Rayleigh-Darcy Convection : A Composite System with Couple Stress Fluid

The influence of linear, parabolic and inverted temperature gradients on the onset double-diffusive Rayleigh-Darcy convection is theoretically investigated. composite system constrained horizontally by adiabatic free-free thermal boundaries, appropriate interfacial boundary conditions are used to connect fluid-porous layers. regular perturbation approach determine critical Rayleigh number expression for different gradients. Graphs investigate significance a variety dimensionless characteristics. couple stress parameter, viscosity ratio, solute number, diffusivity ratio clearly have stabilizing effect system, whereas Darcy destabilize it.