Combined effect of heat source, porosity and thermal radiation on mixed convection flow in a vertical annulus: An exact solution

This paper examines the effect of heat source, thermal radiation and porosity on mixed convection flow in a vertical annulus filled with porous material. The inner surface of outer cylinder is assumed to be the heated surface. Closed-form expression for temperature, velocity, Nusselt number, skin-friction and mass flow rate are obtained in terms of Bessel's function and modified Bessel's function of first and second kind. Based on depicted graphs, fluid temperature and Nusselt number increase with increase in radiation parameter and heat source parameter while velocity as well as skin-friction decreases with increase in radiation parameter and heat source parameter at the surfaces of the cylinder.