Three-Dimensional Laminar Convection in a Parallelepiped with Heating of Two Side Walls

Three-dimensional laminar free convection in a parallelepiped with heating of two side walls with variation of the height-to-width aspect ratio over a wide range $A_x = L/H = 0.1$–$5$ is investigated numerically. The Rayleigh number changed over the range $\mathrm{Ra} = 10^3$–$10^6$. The influence of the volume geometry on the three-dimensional flow structure and heat transfer is studied. It is shown that the three-dimensional character of the flow has a profound effect on heat transmission at a small aspect ratio parameter ($A_x < 1$). For longer length volumes, the whole coefficient of heat emission does not depend on the height-to-width aspect ratio of the enclosure and can be determined from a 2D-approach.