Comparison of transitional intermittency distributions in boundary layers on smooth and rough surface

0376606 - ÚT 2013 RIV SK eng C - Konferenční příspěvek (zahraniční konf.)
Hladík, Ondřej - Jonáš, Pavel - Mazur, Oton - Uruba, Václav
Comparison of transitional intermittency distributions in boundary layers on smooth and rough surface.
XVIII. International Scientific Conference The Application of Experimental and Numerical Methods in Fluid Mechanics and Energy 2012. Žilina: University of Žilina, 2012 - (Lenhard, R.; Kaduchová, K.), s. 53-60. ISBN 978-80-554-0516-2.
[International Scientific Conference The Application of Experimental and Numerical Methods in Fluid Mechanics and Energy 2012 /18./. Demanovská dolina (SK), 25.04.2012-27.04.2012]
Grant CEP: GA ČR(CZ) GAP101/12/1271
Výzkumný záměr: CEZ:AV0Z20760514
Klíčová slova: by-pass transition * rough wall boundary layer * CTA anemometry * instantaneous wall friction * intermittency analysis
Kód oboru RIV: BK - Mechanika tekutin

The paper concerns with the complex effects of free stream turbulence and surface roughness on the transitional intermittency inclusive of spot production rate in the zero pressure gradient boundary layer at low Reynolds number. The conditional analysis of the instantaneous wall friction is applied on time records made in transitional boundary layers originating on smooth surface or surface covered by sand paper (grits 60) under free stream with mean velocity 5 m/s, turbulence level 0.3 or 3 percent and dissipation length parameter from 3.8 mm up to 33.4 mm. Special procedures of measurement and evaluation are applied that allowed evaluations of turbulent and non-turbulent zone averages e.g. the mean durations of the wall friction stays in non-turbulent condition and turbulent condition, the conditionally averaged wall friction and histograms of the wall friction.
Trvalý link: http://hdl.handle.net/11104/0208963