This paper considers the flows induced by symmetrical heating of two vertical parallel surfaces for a Grashof number range of l03-105, a Prandtl number of 0.7, and slot height-to-width ratios of 1.0 and 2.0. A nonorthogonal curvilinear coordinate system in conjunction with an adaptive grid method and second-order accurate discretization schemes were employed in the numerical method. The entire flow field is modeled, including the region beneath the parallel surfaces, the region between the parallel surfaces, the outflow region above, and the downstream wake. The adaptive grid method, based on the concept of equidistribution of a weighting function, clearly shows the evolution of the grid distribution pattern with respect to the change of Grashof number in a way that cannot be prescribed a priori. The resulting improvements of the length scale resolution make the temperature and the velocity fields vary as the Grashof number changes. A converging/diverging convection pattern can be identified within the slot. The effect of aspect ratio on the flow characteristics is also observed, and the slot of unity aspect ratio depicts recirculating eddies for high Grashof numbers.