An Experimental Study of High Rayleigh Number Natural Convection in an Enclosure
An experimental study of high Rayleigh number natural convection in an enclosure was conducted. A water-filled test cell with one vertical wall heated isothermally and the opposite vertical wall cooled isothermally was used. All of the other walls were thermally insulated. The cell had a height-to-width aspect ratio of 10:1; measurements were taken at a Rayleigh number of 8.0 × 1010 based on the height of the isothermal walls. The primary flow occurred in thin regions going up the hot wall and going down the cold wall. Two smaller recirculation vortices adjacent to the primary flow were found. The core was found to be quiescent. Four distinct flow regions were found: laminar, transitional, turbulent, and relaminarization. Mean and fluctuating velocities were measured with a laser-Doppler anemometer system. Mean and fluctuating temperature measurements were measured with fine-wire thermocouples. Spectral analyses of the temperature fluctuations were made with a fast Fourier transform analyzer.