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Towards high-resolution 3D flow field measurements at the cubic meter scale

Schanz, Daniel and Huhn, Florian and Gesemann, Sebastian and Dierksheide, Uwe and van de Meerendonk, Remko and Manovski, Peter and Schröder, Andreas (2016) Towards high-resolution 3D flow field measurements at the cubic meter scale. 18th International Symposium on Applications of Laser Techniques to Fluid Mechanics, 04. - 07. July 2016, Lisbon, Portugal.

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Official URL: http://ltces.dem.ist.utl.pt/lxlaser/lxlaser2016/finalworks2016/papers/03.8_1_249paper.pdf

Abstract

We present results from two large-volume volumetric flow experiments. The first of these, investigating a thermal plume at low velocities (up to 0.35 m/s) demonstrates the abilities and requirements to reach volume sizes up to and probably beyond one cubic meter. It is shown that the use of Helium filled soap bubbles (HFSBs) as tracers, combined with pulsed LED illumination yields high particle image quality over large volume depths. A very uniform particle imaging, both in space as well as in time enables using high particle image concentrations (up to 0.1 ppp), while still being able to accurately reconstruct the flow using Shake-The-Box particle tracking. The experiment consisted of time-resolved volumetric flow measurements of a convectional plume within a volume of approx. 0.55 m3 (550 liters). The light yield needed for such a large scale measurement is realized by using HFSBs with 300 !m diameter as tracers and illuminating the measurement region using high-power, scalable arrays of white LEDs. Applying the Shake-The-Box algorithm, up to 275,000 bubbles could be tracked simultaneously. Interpolating the results on a regular grid (using ‘FlowFit’) reveals a multitude of flow structures. The setup can be scaled to larger volumes of several cubic meters, basically only being limited by the number and power of available LEDs and high-resolution cameras with sufficient frame-rate and pixel sizes. A second experiment showcases the possibilities to reach higher flow velocities, while still measuring within a comparatively large volume, by applying high-speed imaging and advanced LED illumination. An impinging turbulent jet was investigated in volumes ranging from 13 to 47 liters, depending on the repetition rate of the camera system. The results show that even at a repetition rate of 3.9 kHz and flow speeds up to 17 m/s the tested system was able to deliver images that allowed for a reliable and accurate tracking of bubbles.

Item URL in elib:https://elib.dlr.de/101290/
Document Type:Conference or Workshop Item (Speech)
Additional Information:Paper 03.8_1_249
Title:Towards high-resolution 3D flow field measurements at the cubic meter scale
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Schanz, Danieldaniel.schanz (at) dlr.deUNSPECIFIED
Huhn, Florianflorian.huhn (at) dlr.deUNSPECIFIED
Gesemann, Sebastiansebastian.gesemann (at) dlr.deUNSPECIFIED
Dierksheide, UweLaVision, GöttingenUNSPECIFIED
van de Meerendonk, RemkoAerospace Engineering Department, Delft University of Technology, 2629, The NetherlandsUNSPECIFIED
Manovski, PeterDSTG, AustraliaUNSPECIFIED
Schröder, Andreasandreas.schroeder (at) dlr.deUNSPECIFIED
Date:2016
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Page Range:pp. 1-22
Series Name:Conference Proceedings online, Book of Abstracts
Status:Published
Keywords:Lagrangian Particle Tracking, LED volume illumination, Helium filled soap bubbles
Event Title:18th International Symposium on Applications of Laser Techniques to Fluid Mechanics
Event Location:Lisbon, Portugal
Event Type:international Conference
Event Dates:04. - 07. July 2016
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:fixed-wing aircraft
DLR - Research area:Aeronautics
DLR - Program:L AR - Aircraft Research
DLR - Research theme (Project):L - Simulation and Validation
Location: Göttingen
Institutes and Institutions:Institute of Aerodynamics and Flow Technology > Experimental Methods
Deposited By: Micknaus, Ilka
Deposited On:25 Jul 2016 16:33
Last Modified:31 Jul 2019 19:58

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