| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 655335 | International Journal of Heat and Fluid Flow | 2014 | 9 Pages |
Abstract
The existence of meandering superstructures in a turbulent boundary layer overlying irregular roughness is explored with high-frame-rate particle-image velocimetry measurements within the roughness sublayer at moderate Reynolds number. Elongated streamwise fields of view reconstructed from this data using a Taylor's hypothesis approach revealed spanwise-meandering regions of low-streamwise-momentum fluid that extended several boundary-layer thicknesses in the streamwise direction. Such signatures are consistent with previous observations of superstructures in smooth-wall turbulence. Counter-rotating wall-normal vortex cores were found to reside along the spanwise boundaries of these superstructure patterns, consistent with the spatial characteristics of hairpin vortex packets.
Related Topics
Physical Sciences and Engineering
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Authors
R. Mejia-Alvarez, Y. Wu, K.T. Christensen,