Numerical study on natural convection and entropy generation in squares and corrugated cavities

The present work deals with the study of the entropy generation in the natural convection process in both square cavities and square cavities with hot wavy walls through numerical simulations for different undulations and Rayleigh numbers, while keeping the Prandtl number constant. The results show that the heat transfer rate is notably affected by the shape of the hot wall geometry compared with the square one. It has been found in this investigation that the mean Nusselt number in the case of heat transfer in a cavity with wavy walls is lower, as compared to heat transfer in a cavity without undulations. Based on the obtained dimensionless velocity and temperature values, the distributions of the local entropy generation due to heat transfer and fluid friction, the local Bejan number, and the local entropy generation are determined and plotted for different undulations and Rayleigh number. The study is performed for Rayleigh number 10⁵ <Ra<10⁷ irreversibility coefficients 10⁻⁴< ϕ <10⁻². The total entropy generation is found to increase with increasing undulation number