Book excerpt: Heat transfer characteristics and associated temperature and flow fields for natural convection in two-dimensional, square, partitioned and non-partitioned enclosures have been determined for Grashof numbers ranging from 103 to 106. The vertical side walls of the enclosure are isothermal with all other surfaces assumed to be adiabatic. An adiabatic partition is oriented vertically with one edge on the enclosure floor. The dimensions and location of the partition were varied in order to investigate its effect of natural convection in the enclosure. Air was taken as the working fluid. Transport equations for vorticity and energy were solved using the QUICKEST scheme while the Poisson equation, for the steamfunction, was solved using the SOR method. For any Grashof number, temperature and flow fields in the region above the partition are not significantly different from those of the non-partitioned enclosure in the case of an aperture ratio of 0.75 or greater. An increase in the partition height or width results in modifying the temperature and flow fields and decreasing the average heat transfer across the enclosure.