Impact of wall roughness elements type and height on heat transfer inside a cavity

This work investigates the effect of two wall roughness types, triangular and circular, on convection and radiation heat transfer in a small space. The ANSYS Fluent is used to do thermal and dynamic modeling; the left wall is warmer than the right one. The upper and lower walls are adiabatic. The Nusselt numbers are compared in all cases and for two Rayleigh values, which change based on the cavity's characteristic length. The results show temperature contours and Nusselt curves. It was observed that the roughness had a strong effect on the air's thermal behavior inside the cavity, where the Nusselt decreased in both roughness cases, especially at small heights. However, the largest decrease is in the triangular case and for angles less than 90°. For 72°, Nusselt is 13.32 and 6% less than smooth and circular cases respectively.