Abstract
The problem of free convection flow and heat transfer of a fluid inside a square cavity having adiabatic obstacle positioned in the center of the cavity has been investigated numerically using a penalty finite element method. Calculations have been made for Rayleigh numbers ranging from 10(2) to 10(7) for an obstacle of aspect ratios AR = 0, 0.4, 0.5, 0.6. Nusselt number results are presented for Prandtl number of 0.71 (assuming the cavity is filled with air). Streamline and isotherm contours are also presented. The obtained results demonstrate the effects of pertinent parameters on the fluid flow, thermal fields and heat transfer inside the cavity. The results show that the heat transfer rates generally increase with the shrink of the obstacle size and with the increase of Rayleigh number. Excellent agreement is obtained with previous results in the literature.