Steady natural convection in a cylindrical cavity

We present a numerical and experimental study of steady natural convection in a small aspect ratio cylindrical cavity with circular cross section. The main objective of the present communication is to highlight some difficulties encountered when a comparison of theoretical and experimental velocity results is attempted. We keep the aspect ratio (radius/height), the Prandtl number and the Rayleigh number fixed to 0.28, 6 and 2.25 × 106 respectively and make observations in a vertical plane that contains the axis of symmetry of the cylinder with a particle image velocimetry (PIV) technique. The main structure present in the flow is a single non-axisymmetric cell with a horizontal rotation axis. Due to the symmetry of the geometry of the cavity and of the heating and cooling systems, the orientation of the convective structure is undefined by the boundaries. In order to make a theoretical-experimental comparison, it is necessary to make a full description of the three dimensional velocity field to find the plane that corresponds to the one observed in the experiment.