Entropy generation and natural convection in a wavy-wall cavity filled with a nanofluid and containing an inner solid cylinder

This work investigates the problem of entropy generation and natural convection in a wavy-wall cavity filled with a nanofluid and containing solid inner cylinder using the Galerkin finite-element method. An isothermal heat source fixed at the left vertical wall of the cavity and the horizontal walls have taken adiabatic, while the right wavy wall cooled isothermally. An Al₂O₃-water nanofluid fills the space between the wavy-wall cavity and the solid cylinder. To study this problem, the influence of three variables have taken into account. These variables are Rayleigh number (10³ ≤ Ra ≤ 10⁶), nanoparticle volume fraction (0 ≤ ≤ 0.04), and the number of undulations (1≤ N ≤ 4). The numerical results can be in the forms of streamlines, isotherms and local entropy generation as well as the average Nusselt number. The obtained results indicate that the effect of the nanoparticles addition on the heat transfer rate is essential for low Rayleigh number and number of undulations.