The effect of ordered structure of turbulence on momentum, heat and mass transfer of impinging round jets

The interaction of vortex structure of the round free jet with the plane solid surface has been investigated using the 'smoke wire' flow visualization and skin friction measurements. The more precise explanation of the mechanism of the influence of the large-scale ordered flow structure on the heat or mass convective processes in the transient region of the impinging round jet has been presented. It was observed that toroidal vortices are periodically generated at the edge of the nozzle and grow to produce the well ordered flow structure at the plate. A periodic appearance of ring-like wall eddies which are rolled up on the wall surface between the radially stretched large-scale toroidal vortices has been recorded. The radial distribution of the skin friction obtained with the thermoanemometry flush mounted probe appears to be generally consistent with the impingement heat transfer data with the exception of the strong acceleration zone in the stagnation point vicinity.