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Published in:
2010 | OriginalPaper | Chapter
3D Structures from Stereoscopic PIV Measurements in a Turbulent Boundary Layer
Authors : David J. C. Dennis, Timothy B. Nickels
Published in: Progress in Turbulence III
Publisher: Springer Berlin Heidelberg
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Experiments using stereoscopic high-speed particle image velocimetry (PIV) to take measurements in a cross-stream (i.e. wall-normal/spanwise) plane in a turbulent boundary layer have been used to produce full 3D velocity fields. The 3D fields were constructed from planar 3C fields by using Taylor’s hypothesis to create a pseudo-spatial x-dimension from the temporally resolved measurements. This has produced a 3D viewof the elongated regions of high and low streamwise momentum found in the boundary layer, often referred to as ‘long structures’, and provided information on the arrangement, length and characteristic angle of these structures. Long structures are also seen to be associated with regions of high Reynolds stress. Vortical motions are visualised using swirling strength, and indicate that there is a prevalence for vortices to surround the low speed long structures. The vortices are characterised, and are found to resemble hairpin vortices in some respects.