Experimental and Numerical Investigations of Transient Natural Convection in Differentially Heated Air-Filled Tall Cavity

The two-dimensional laminar natural convective transient flow characteristics in a differentially heated air-filled tall cavity with gradual heating are investigated both experimentally and numerically for various parameters such as Rayleigh number and temperature difference. Experimental computations are performed for temperature difference varying from (∆T = 5°C) to (∆T = 23°C) while the Rayleigh number varies from (Ra = 2929) to (Ra =11772) to cover a wide range of the flow field inside the cavity. The results show that as the Rayleigh number increases the flow becomes unstable. Also, the flow characteristics are observed to be multi-cellular and time variant especially at high Rayleigh numbers. Moreover, numerical computations are performed to compare with the experimental results.