Natural convection cooling of rectangular and cylindrical containers

Scalings are obtained for the development of unsteady natural convection, b oth in rectangular and vertical circular containers, and are validated by c omparison with results obtained using direct numerical simulation. It is fo und that the numerical results agree well with the scalings. Three main sta ges of flow evolution are identified and the differences at each of these s tages between the rectangular and cylindrical geometries are quantified. It is shown that in the flow regimes considered there is a difference in ther mal boundary layer thickness; that the horizontal intrusion layer has a uni form thickness for the rectangular flow, but increases towards the symmetry axis for the cylindrical flow; and that the rate of stratification is much faster for the cylindrical geometry. (C) 2001 Elsevier Science Inc. All ri ghts reserved.