Benchmark Comparison of Natural Convection in a Tall Cavity

H. Dillon[1]
[1]Department of Mechanical Engineering, University of Washington, Seattle, Washington, USA

A comparison of the commercial code COMSOL is performed with the bench-mark solutions provided by the literature for a tall, differentially heated rectangular cavity for aspect ratios of 8, 15, 20, and 33. At small Rayleigh numbers the flow is dominated by conduction. As the Rayleigh number is increased the flow becomes unstable, first resulting in multicellular secondary flow patterns, and then as the Rayleigh number is further increased becoming turbulent. For this work a range of Rayleigh numbers from 1e3 to 3e5 is considered for a Prandtl number of 0.71. The predicted wavenumber, critical Rayleigh number, and characteristic stream functions are compared with experimental work reported in the literature. The effect of COMSOL's anisotropic and crosswind numerical diffusion values are also evaluated.