Key words: natural convection, heat source, Rayleigh number, heat transfer, boundary conditions.

Abstract: The present work deals with the prediction of a natural convection flow in a square cavity, partially heated by an obstacle placed at the bottom wall. The two transverse walls and the top wall of the cavity are supposed to be cold. The main parameter of numerical investigations is the Rayleigh number (engine convection) ranging from 103 to 105. Different configurations relative to cooling obstacle are presented and analyzed in the current study. The simulations were conducted using a numerical approach based on the finite volume method and the projection method, which are implemented in a computer code in order to solve the Navier-Stokes equations.