A scale analysis of turbulent heat transfer driven by buoyancy in a porous layer with homogeneous heat sources

A heat transfer analysis is conducted for the turbulent natural convection in a porous layer with homogeneous heat sources. It is assumed that the top and the bottom of the layer is cooled at a constant temperature and insulated, respectively. Darcy's law is used to explain characteristics of fluid motion. Through a scale analysis on the turbulent heat and momentum transfer, a scale relation for Nusselt number is derived as a function of Rayleigh number. With the aid of available experimental and analytical results, Nusselt number correlations are proposed. The critical Rayleigh number for the onset of convection is also mentioned. (C) 2002 Elsevier Science Ltd.