Natural convection heat transfer above heated horizontal surfaces

An extensive reasoned review of the results available in the literature for free convection heat transfer from a heated flat plate facing upwards, is conducted. The review is organized in the form of a table, so as to give the reader the opportunity to compare the heat transfer data, expressed through dimensionless equations, as well as the conditions under which these data were obtained. A comparative survey of the results which may be derived at different Rayleigh numbers by the use of the heat transfer correlations presented, is also reported, showing that in some cases the discrepancies may amount to 50%.