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Non-rotational coherent structures in the flow with different degree of turbulence

SYSNO ASEP	0480033
Document Type	C - Proceedings Paper (int. conf.)
R&D Document Type	The record was not marked in the RIV
Title	Non-rotational coherent structures in the flow with different degree of turbulence
Author(s)	Kellnerová, Radka (UT-L)_{RID, ORCID} Jurčáková, Klára (UT-L)_{RID, ORCID} Nosek, Štěpán (UT-L)_{RID, ORCID} Jaňour, Zbyněk (UT-L)_{RID, ORCID}
Publication form	Online - E
Action	Symposium on Boundary Layers and Turbulence /22./
Event date	20.06.2016 - 24.06.2016
VEvent location	Salt Lake City
Country	US - United States
Event type	WRD
Language	eng - English
Keywords	coherent structure ; turbulence ; PIV ; correlation ; quadrant analysis
Subject RIV	DG - Athmosphere Sciences, Meteorology
R&D Projects	GA15-18964S GA ČR - Czech Science Foundation (CSF)
Institutional support	UT-L - RVO:61388998
Annotation	The coherent structures are not satisfactorily defined for a very complex atmospheric flow. The features with a rotational motion, namely the vortices and hairpins, are mostly considered as a typical coherent pattern. In the turbulent flow, however, the non-rotational transient phenomenon may play a crucial role. The boundary layer dynamics above surfaces of various roughness was measured in the wind-channel by 2D 2C TR-PIV. The data recorded with the high sampling frequency were analysed by means of coherence detection methods. Firstly, the spatial correlation of the longitudinal and vertical velocity component is calculated and a tilt angle of the area with significant correlation coefficient is retrieved. Secondly, the Quadrant analyses applied to the momentum flux at each snapshot revealed that the spatially compact regions of the uniform sweep and ejection events contained up to 80% of the total momentum flux.
Workplace	Institute of Thermomechanics
Contact	Marie Kajprová, kajprova@it.cas.cz, Tel.: 266 053 154 ; Jana Lahovská, jaja@it.cas.cz, Tel.: 266 053 823
Year of Publishing	2018

Number of the records: 1