This paper presents Large Eddy simulations of a compressible turbulent flow through a duct of square cross- section with a discrete heating source on its bottom wall. The potential interest is related to numerous engineering applications. In the first part of this study, a non heated duct was considered. Tow values of Reynolds number are investigated (Re=8000 and Re=10000). The secondary flow characteristic of this type of flow was highlighted and the intensification of turbulent structures with the Reynolds number was revealed. In the second part, the effect of the discrete heating source is studied without considering gravity effects. It was found that the coherent turbulent structures are enhanced in size and a strong intensification of ejection and sweeps phenomenon are shown at the level of the heating source.