A combined numerical-experimental study of convection in an axisymmetric differentially heated fluid layer

Buoyancy-driven convection in-a horizontal differentially heated fluid layer has beer analysed numerically and compared with the experimental results obtained for a circular axisymmetric fluid layer, the :side walls of the cavity being thermally insulated and of constant radius. The employed Rayleigh numbers are 5861 and 12, 124 and the working fluid air. The governing equations are continuity equation, Navier-Stokes equation and the energy equation. Due to the axisymmetric nature of the fluid cavity, the governing equations have been solved in r-z coordinate system. A fine uniform grid of 601x81 is employed. Experiments have been conducted in the fluid layer of 0.64 in diameter and 23 mm vertical height with the same working fluid as considered in numerical simulation. A Mach-Zehnder interferometer has been used to visualize the long-time convection patterns in the fluid layer. The goal of the study is to investigate the influence of Rayleigh number on the steady (long time) thermal field, quantitative analysis of heat transfer rates and comparison with the experimental results. A good agreement has been found in qualitative as well as quantitative sense between theoretical and experimental results.