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Tomographic PIV investigation of coherent structures in a turbulent boundary layer flow

Tang, Zhan-Qi and Jianga, Nan and Schröder, Andreas and Geisler, Reinhard (2012) Tomographic PIV investigation of coherent structures in a turbulent boundary layer flow. Acta Mechanica Sinica, 28 (3), pp. 572-582. Springer Verlag, Heidelberg. DOI: 10.1007/s10409-012-0082-y. ISSN 0567-7718.

Full text not available from this repository.

Official URL: http://link.springer.com/journal/10409/28/page/1

Abstract

Tomographic particle image velocimetry was used to quantitatively visualize the three-dimensional coherent structures in the logarithmic region of the turbulent boundary layer in a water tunnel. The Reynoldsnumber based on momentum thickness is Reθ =2, 460. The instantaneous velocity fields give evidence of hairpin vortices aligned in the streamwise direction forming very long zones of low speed fluid, which is flanked on either side by high-speed ones. Statistical support for the existence of hairpins is given by the conditional averaged eddy within an increasing spanwise width as the distance from the wall increases, and the main vortex characteristic in the different wall-normal regions can be reflected by comparing the proportion of ejection and its contribution to Reynolds stress with the case of sweep event. The pre-multiplied power spectra and two-point correlations indicate the presence of large-scale motion in the boundary layer, which are consistent with what have been termed VLSM (very large scale motions). The three dimensional spatial correlations of three components of velocity further indicate that the elongated low-speed and high-speed regions will be accompanied by a counter-rotating roll modes, as the statistical imprint of hairpin packet structures, all of which together make up the characteristic of coherent structures in the logarithmic region of the turbulent boundary layer (TBL).

Document Type:Article
Title:Tomographic PIV investigation of coherent structures in a turbulent boundary layer flow
Authors:
AuthorsInstitution or Email of Authors
Tang, Zhan-QiDepartment of Mechanics, Tianjin University, 300072 Tianjin, China
Jianga, NanDepartment of Mechanics, Tianjin University, 300072 Tianjin, China
Schröder, Andreasandreas.schroeder@dlr.de
Geisler, Reinhardreinhard.geisler@dlr.de
Date:2012
Journal or Publication Title:Acta Mechanica Sinica
Refereed publication:Yes
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:28
DOI:10.1007/s10409-012-0082-y
Page Range:pp. 572-582
Publisher:Springer Verlag, Heidelberg
ISSN:0567-7718
Status:Published
Keywords:Tomographic particle image velocimetry; turbulent boundary layer; coherent structures; hairpin vortex; very large scale motion
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:Aircraft Research (old)
DLR - Research area:Aeronautics
DLR - Program:L AR - Aircraft Research
DLR - Research theme (Project):L - Simulation & Validation (old)
Location: Göttingen
Institutes and Institutions:Institute of Aerodynamics and Flow Technology > Experimental Methods
Deposited By: Ilka Micknaus
Deposited On:01 Aug 2012 09:59
Last Modified:01 Sep 2014 16:15

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