Nowadays, many industrial and modern applications depend on heat transport in porous zones. An experimental study of the natural convection heat transfer in a corrugated cavity with dimensions of (200, 250, 300) mm in length, a width of 200 mm, a depth of 27 mm, and an amplitude of 30 mm was filled with porous materials: glass balls (3, 6, 10) mm and alumina balls (6) mm, where the water was the working fluid. The top surface was exposed to the environment, while the bottom surface was subjected to constant heat flux (300, 500, 700, 900, 1100 W/m2), The front face, back face, and sides were insulated. In this study, temperature distribution, modified Rayleigh number, and Nusselt number values are foremost criteria, which are presented for three levels of aspect ratio. The influence of various aspect ratios on heat transfer is investigated. The results showed that the heat transfer coefficient decreases with the increase in aspect ratio. The highest value is when aspect ratio = 1. The enhanced Rayleigh number decreases as the aspect ratio increases by 10%.