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High-speed particle image velocimetry for the efficient measurement of turbulence statistics

Willert, Christian and Klinner, Joachim (2015) High-speed particle image velocimetry for the efficient measurement of turbulence statistics. MOTAR Meeting 2015, 15.-16. Apr. 2015, Cologne, Germany.

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Abstract

A high frame rate camera and a continuous wave laser are used to capture long particle image sequences exceeding 100,000 consecutive frames at framing frequencies up to 50 kHz. The electronic shutter of the high-speed CMOS camera is reduced to 5\mu s to prevent excessive particle image streaking. The combination of large image number and high frame rate is possible by limiting the field of view to a narrow strip to primarily capture a profile of velocity data and derived quantities, such as vorticity and higher order statistics. Multi-frame PIV processing algorithms are employed to improve the dynamic range of recovered PIV data. The recovered data is temporally well resolved and provides sufficient samples for statistical convergence of the fluctuating velocity components. The measurement technique is demonstrated on a developing turbulent duct flow inside a small wind tunnel with Re_\delta = 4800 and Re_\theta = 490 as well as on a turbulent boundary layer in the 1m wind tunnel of DLR-Göttingen with Re_\delta = 34000 and Re_\theta = 4000. By means of single-line correlation it is further possible to extract the near wall velocity profile in the viscous sub-layer, both time-averaged as well as instantaneous, which can then be used to estimate the wall shear rate and with it the shear stress \tau_w and friction velocity u_\tau.

Item URL in elib:https://elib.dlr.de/101854/
Document Type:Conference or Workshop Item (Speech)
Title:High-speed particle image velocimetry for the efficient measurement of turbulence statistics
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Willert, Christianchris.willert (at) dlr.deUNSPECIFIED
Klinner, Joachimjoachim.klinner (at) dlr.deUNSPECIFIED
Date:April 2015
Refereed publication:No
Open Access:No
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Status:Published
Keywords:turbulent boundary layer, particle image velocimetry, PIV, wall shear stress, high speed imaging
Event Title:MOTAR Meeting 2015
Event Location:Cologne, Germany
Event Type:international Conference, Workshop
Event Dates:15.-16. Apr. 2015
Organizer:DLR Institut für Antriebstechnik
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:propulsion systems
DLR - Research area:Aeronautics
DLR - Program:L ER - Engine Research
DLR - Research theme (Project):L - Virtual Engine and Validation methods
Location: Köln-Porz
Institutes and Institutions:Institute of Propulsion Technology > Engine Measurement Systems
Deposited By: Willert, Dr.phil. Christian
Deposited On:08 Jan 2016 14:19
Last Modified:08 Jan 2016 14:19

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