N. Srivastava - Department of Mathematics, Banaras Hindu University, Varanasi-۲۲۱۰۰۵, India
A. K. Singh - Department of Mathematics, Banaras Hindu University, Varanasi-۲۲۱۰۰۵, India

A combined convection process between two parallel vertical infinite walls, containing an incompressible viscous fluid layer and a fluid saturated porous layer has been presented analytically. There is a vertical axial variation of temperature in the upward direction along the walls. The Brinkman extended Darcy model is applied to describe the momentum transfer in the porous region. The viscosity of the fluid layer and the effective viscosity of the porous layer are assumed to be different. Also the thermal conductivities of both fluid and porous layers are assumed to be different. The graphs and tables have been used to distinguish the influence of distinct parameters on the velocity and skin-friction. It is determined that the velocity is intensified on making greater the temperature difference between the walls while increment in the viscosity ratio (porous/fluid) parameter diminishes the velocity of the fluid. It has been observed that the numerical values of the skin-frictions have an increasing tendency with the increment in the values of temperature difference between the walls while decreasing tendency with the increment in the viscosity ratio parameter (porous/fluid).

composite system, Mixed convection, effective viscosity, Porous media, Brinkman model