Open AccessThe sweep down flow and “contra-hairpin vortex” in a turbulent boundary layer
Author(s) -
Lian Qixiang,
Guo Hui
Publication year - 2004
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.53.2226
Subject(s) - boundary layer , vortex , turbulence , flow (mathematics) , mechanics , layer (electronics) , flow separation , physics , materials science , nanotechnology
The sweep down flow and related flow structures in a turbulent boundary layer were visualized with hydrogen bubble method. The streamwise and transverse vortices induced by sweep down flow near the wall of a vessel were observed. A new kind of vortical structure, whose features are contrary to those of the hairpin vortex, was observed in the present experiments. It is termed “contrahairpin vortex” here. Its head points upstream, while the head of a hairpin vortex points downstream; lift-up flow is induced between the legs of a hairpin vortex, while between the legs of this new vortical structure, sweep down flow is induced.