Natural Convection Heat Transfer Performance of Non-Newtonian Power-Law Fluids Enclosed in Cavity With Complex-Wavy Surfaces

Numerical simulations are performed to investigate the natural convection heat transfer performance of non-Newtonian power-law fluids in a cavity bounded by wavy vertical walls with different temperatures and flat horizontal walls under adiabatic conditions. The results show that for Rayleigh numbers greater than 10³, the mean Nusselt number has a significantly increase as the flow behavior index is decreased. Moreover, it is shown that in the convection-dominated regime, the mean Nusselt number increases with an increasing Rayleigh number, while in the conduction-dominated regime, the mean Nusselt number remains approximately constant. Finally, it is shown that for a given fluid, the heat transfer performance can be optimized via an appropriate tuning of the wavelength and amplitude of the wavy surface depending on the Rayleigh number.