Unsteady Natural Convection Flow through a Vertical Channel: Due to the Combined Effects of Variable Viscosity and Thermal Radiation

Abstract

The paper investigates unsteady natural convection flow through a vertical channel due to the combined effects of variable viscosity and thermal radiation. The fluid considered in this study is an optically dense viscous incompressible fluid with all its properties assumed to be constant except for its viscosity which depends linearly with its temperature. Non-linear Rosseland approximation is used to describe the radiative heat flux in the energy equation. The mathematical model capturing the present physical situation is highly non-linear due to the presence of thermal radiation effects. The governing equations for the flow formation are solved by the Adomian decomposition method (ADM). Effects of the controlling physical parameters involved in the velocity and temperature fields are presented graphically and discussed. In the course of investigation, it was found that; the fluid velocity increases with increase in thermal radiation and viscosity variation parameters while the fluid temperature increases with increase in thermal radiation.