Existence of a steady state of a natural convective flow in a confined medium

Experimental results are presented from a study of convective flow in a parallelipiped-shaped cavity with walls maintained at different temperatures. Resistive heaters permitted varying the wall temperatures up to 150 C, and the container could be tilted from 0-90 deg. Air was used as the fluid medium, with Rayleigh numbers from 2000-1,000,000. The flows studied featured the appearances of both steady and unsteady instabilities. Attention was given to vertical movements and a two-dimensional numerical model was defined. Attempts were made to identify the limits of a steady state in terms of the Rayleigh number, the shape factors, and the tilt of the cavity.