The Relation between the Internal Structure of the Coherent Vortex and Heat Transfer Processes
The paper presents an experimental analysis concerning the mutual relation between the structure of coherent vortices existing in the round, free jet and their involvement into the transport processes realized in this type of flow. The heat transfer processes are usually treated in a manner analogous to momentum transport phenomena, even in the flows containing the organized vorticity, where much larger scales are encountered than in the classical, random turbulence. The above processes become a complex matter when the existence of coherent structures is taken into account, because in this case the turbulent diffusion is being replaced by large scale convection, as the major transport mechanism. The axisym- metric free jet has been chosen as the flow case studied, because of the simultaneous presence of several different modes of organized motion characterized by substantially different scales. The advanced visualization experiments used contemporarily  allow to trace the dynamics of coherent vortices but they can not give the quantitative information concerning the transport properties of the phenomena studied. That is why it has been decided to apply the proper computer-aided data processing that would enable to reconstruct the flowfields related to oganized and random components of turbulent motion, respectively. Furthermore the small overheat of the flow has also been applied, which enabled to trace the mutual interactions of velocity and temperature fields.
KeywordsCoherent Structure Strouhal Number Heat Transfer Process Coherent Vortex Large Scale Convection
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