a jet impinging on a flat obstacle with swirling and combustion of a propane–air mixture with
an equivalence ratio of 0.7 for a nozzle–obstacle distance H/d= 1 and 3 and in the absence
of the obstacle. The swirl ratio was 0.41 and 1.0, and the Reynolds number was 5 000. It is
concluded that for both values of the swirl ratio, the presence of the impact surface leads to
the formation of an extended central cone-shaped recirculation zones. For H/d= 3 and 2, the …