| Abstract [eng] |
Flow separation phenomena have a considerable impact on mass, momentum, and heat transfer processes in flowing fluids and their mixing processes. These phenomena are the main reason why separated flow remains a research object in engineering. Furthermore, they are a source for a deeper understanding of the internal mechanism of vortex formation, interaction, and disintegration. The aim of this work is to investigate fluid flow dynamics and structure in channels with abrupt cross-section changes and to determine the characteristics of recirculating flow depending on flow regime and channel geometrical parameters using experimental and numerical approaches. By this work the knowledge of recirculation zone structure and length dynamics for different cavity types, depending on cavity geometrical parameters (H/h and L/h1) is improved. Also, determined dependencies and patterns of physical recirculation zone parameters for laminar and turbulent flow regimes. Revealed causes of the effect of channel expansion ratio (H/h) and Re for dynamics of recirculation zone length, which helps to explain the scattering of other authors’ results and suggest possible scaling for laminar and turbulent flow regimes. Results of this work are significant for a large number of engineering problems where flow separation is induced by abrupt changes of channel cross-section, which can be analyzed as flows over cavities in a channel. |
