Transient Behavior Inside a Vertical Cylindrical Enclosure Heated from the Side walls

Abstract
A study of the transient laminar free convection in a vertical cylindrical annulus filled with air Pr = 0.71 is conducted numerically and analytically. The governing equations are solved numerically by considering the transient resolutions (direct numerical simulation) in a two-dimensional domain (angular symmetry) using a control-volume numerical approximation. The time evolution is reported in terms of various parameters such as the cylinder curvature and the Rayleigh number. The results reveal that the required time to reach steady state decreases with the convection intensity and is independent of the curvature.