Benchmark Comparison of Natural Convection in a Tall Cavity

A comparison of the commercial code COMSOL is performed with the bench- mark solutions provided by the literature for a tall, dierentially heated rectangular cavity for aspect ratios of 8, 15, 20, and 33. At small Rayleigh numbers the ow is dominated by conduction. As the Rayleigh number is in- creased the ow becomes unstable, rst result- ing in multicellular secondary ow 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 num- ber, and characteristic streamfunctions are compared with experimental work reported in the literature. The eect of COMSOL's anisotropic and crosswind numerical diusion values are also evaluated.