Structure Identification and Analysis in Turbulent Boundary Layers by Stereo PIV

E. K. Longmire, B. Ganapathisubramani, I. Marusic, T. Urness

Research output: Contribution to journalConference articlepeer-review

Abstract

Stereoscopic PIV was used to measure three instantaneous components of velocity in streamwise-spanwise planes of a turbulent boundary layer. The local boundary layer thickness was δ = 69 mm, and the corresponding Reynolds number based on friction velocity was 1060. Data sets were obtained in the log region at wall-normal positions of z+ = 92 and z+ = 192. The resulting velocity fields at z+ = 92 revealed distinctive signatures of vortex packets similar to those observed by Adrian, Meinhart, & Tomkins (2000). At this height, trains of 'necks' from hairpin vortices were observed aligned with the streamwise direction. The packets, which were frequently associated with high levels of Reynolds stress, appear to be a dominant mechanism for near-wall momentum transport. At z- = 192, larger individual vortex cores and heads of hairpin vortices were observed, but packet structures within the plane were not as evident.

Original languageEnglish (US)
Pages (from-to)1449-1455
Number of pages7
JournalDLR-Mitteilung
Issue number3
StatePublished - Dec 1 2001
EventParticle Image Velocimetry - Gottingen, Germany
Duration: Sep 17 2001Sep 19 2001

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