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The effect of partition on turbulent natural convection has been investigated numerically with different lengths and positions in an air filled square cavity. The top wall of the cavity is assumed to be cold and the other three walls are hot. Two-dimensional governing equations based on Reynolds-averaged Navier-Stokes equations are solved numerically by control volume method in a staggered grid manner. The iterative SIMPLE algorithm is also used to solve the discretized momentum equations to compute the intermediate velocity and pressure fields linked through the momentum equations. The hybrid differencing scheme which is based on a combination of central and upwind schemes is employed to discretize the convective and diffusion terms of the equations respectively. To describe the structure of turbulent flow which is changed due to the increasing importance of viscous effects, wall function was applied to simulate the turbulent flow. The results show that when the partition is placed on the top or bottom wall, the heat transfer rate through the bottom wall increases by increasing the partition length. The number of vortices established in the cavity depends on the partition length. Furthermore, when the partition is mounted on the left or right wall, only a small part of the top wall has a direct interaction with the left wall and the rest of that has an indirect interaction with the bottom wall.

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In this study, turbulent natural convection in a square enclosure including one or four hot and cold bodies is numerically investigated in the range of Rayleigh numbers of 10 10 < Ra < 10 12. The shape of the internal bodies is square or rectangular with the same surface areas and di erent aspect ratios. In all cases, the horizontal walls of the enclosure are adiabatic, and the vertical ones are isothermal. It is desired to investigate the in uence of di erent shapes and arrangements of internal bodies on the heat transfer rate inside the enclosure with wide-ranging applications such as ventilation of buildings, electronic cooling, and industrial cold box packages. Governing equations, including Reynolds-averaged-Navier-Stokes equations, have been solved numerically with nite volume method and k " turbulence model in a staggered grid. The boundary condition for the turbulence model is based on the standard wall function approach. The strongly implicit method is employed to solve the discretized systems of algebraic equations with a remarkable rate of convergence. The e ects of several parameters, such as the distance between the bodies, aspect ratio, and Rayleigh number, on the heat transfer rate have been investigated. The most noticeable change in the heat transfer rate at high values of Rayleigh numbers is associated with alteration in the distance between square bodies. Moreover, the horizontal installation of rectangular bodies with h=w = 1=3 is accompanied by a maximum reduction of heat transfer at low Rayleigh numbers. The present results have been compared with previous experimental and numerical works regarding enclosures with or without internal bodies. Then, reasonable agreement is observed.