Lattice Boltzmann simulation of turbulent natural convection in tall enclosures

In this paper Lattice Boltzmann simulation of turbulent natural convection with large eddy simulations in tall enclosures which is filled by air with Pr = 0.71 has been studied. Calculations were performed for high Rayleigh numbers (Ra = 10⁷ -10⁹ ) and aspect ratios change between 0.5 and 2 (0.5 < AR < 2). The present results are validated by finds of an experimental research at Ra = 1.58·10⁹ . Effects of the aspect ratios in different Rayleigh numbers are displayed on streamlines, isotherm counters, vertical velocity and temperature at the middle of the cavity, local Nusselt number and average Nusselt number. The average Nusselt number increases with the augmentation of Rayleigh numbers. The increment of the aspect ratio causes heat transfer to decline in different Rayleigh numbers.