Abstract:

Vortices have been referred to as the "sinews and muscles" of both turbulence and general fluid mixing.  However, we still have much to understand about how vortices are generated, behave, and interact with other vortices and with adjacent surfaces.  The studies to be discussed have been done to expand our understanding of vortex development and interactions, with a view toward better understanding the part that vortices play in turbulence, mixing, and surface heat transfer.

The results of several studies will be reviewed, encompassing the development and evolution of the flow structure and heat transfer for a turbulent boundary layer and the end-wall juncture region of bluff bodies with turbulent approach boundary layers.  The end-wall region is examined since it exhibits a rich array of relatively well-behaved and repeatable, three-dimensional and unsteady vortex flow structures.  The flow behavior and structure is examined in a water flow using hydrogen bubble, PIV, and liquid crystal temperature sensing.  The end-wall visualization/velocity studies reveal the systematic development and behavior of and organized three-dimensional vortex flow regimes.  The spatial-temporal velocity/vorticity fields reveal the mechanism of vorticity generation and dissipation during vortex-surface interaction. The spatial-temporal surface heat transfer patterns due to both a turbulent boundary layer and end-wall vortex behavior are also examined using liquid crystal thermography.  Using simultaneous velocity-heat transfer imaging of the end-wall flows it is illustrated how surface heat transfer varies dramatically with vortex proximity, demonstrating the importance of vortex interactions in elevating surface heat transfer.

Brief Biograph:

Dr. Smith is an Emeritus Professor of Mechanical Engineering at Lehigh University, Bethlehem, Pennsylvania, and is internationally recognized for his research in fluid mechanics, particularly the areas of turbulent flow, unsteady flow effects, fluid and thermal flow visualization techniques, and flow mixing and conditioning.

Dr. Smith has published over 100 papers and two text books. Dr. Smith is also past Chair of the Department of Mechanical Engineering and Mechanics, served on several editorial review boards, has consulted for over twenty five different industrial companies, and has provided expert testimony and forensic engineering.  In 1987, Dr. Smith co-founded the VORTAB Corporation, a company that manufactured and marketed low-loss flow conditioners and fluid mixing devices for pipe flows. From 1997 to 2005 he was a member of the Board of Directors of Penn Engineering & Manufacturing Company in Danboro, PA.

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