The mixing between a hot turbulent flow and a cold fluid, injected through a porous plate or using a discrete injection, is experimentally investigated. The blowing is shown to dramatically modify the dynamic and thermal fields, whereas the discrete injection has a weaker effect. The influence on the average quantities and fluctuating parts are found to be different. The effect of the main flow temperature is addressed and a discussion for the mixing in the blowing and discrete injection cases is proposed.Knowing how hot and cold gases mix in such protecting processes as film cooling [1][2][3][4] or blowing [5] is a very important and fundamental issue in heat transfer. Such studies are applied in engineering problems, including blade protection and combustor wall cooling in gas turbines.A review of blowing literature shows many investigations [6,7] that deal with the effect of injection on the friction factor and on the heat transfer. Some of them focusing on the influence of the Reynolds Number [8] and of the main flow turbulence level [9]. Baskarev et al.[10] investigated the influence of the injection rate on heat transfer within a boundary layer over a porous wall.