Abstract
Porous medium has been studied extensively for many years but still the field offers many problems for new generation of researchers. The current article is aimed to investigate one such problem that is influence of radius ratio on the heat transfer behavior in a porous medium fixed in annular cylinder. This article is particularly focused on effect of radius ratio which is the ratio of width of porous medium to the inner radius of annuls. The outer surface of annulus is maintained at hot isothermal temperature whereas the inner radius is maintained at cold isothermal temperature. Results are discussed in terms of Nusselt number. It is found that the radius ratio affects the heat transfer behavior substantially for problem under consideration.