Huhn, Florian und Schanz, Daniel und Gesemann, Sebastian und Dierksheide, Uwe und van de Meerendonk, Remco und Schröder, Andreas (2017) Large-scale volumetric flow measurement in a pure thermal plume by dense tracking of helium-filled soap bubbles. Experiments in Fluids, 58 (116), Seiten 1-19. Springer Nature. doi: 10.1007/s00348-017-2390-2. ISSN 0723-4864.
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Offizielle URL: https://doi.org/10.1007/s00348-017-2390-2
Kurzfassung
We present a spatially and temporally highly resolved flow measurement covering a !arge volume (~o.6 m3) in a pure thermal plume in air. The thermal plume develops above an extended heat source and is characterized by moderate velocities (U~0.35 m/s) with a Reynolds number of Re~500 and a Rayleigh number of Ra~100000. We demonstrate the requirements and capa bilities of the measurement equipment and the particle tracking approach to be able to probe measurement volumes up to and beyond one cubic meter. The use of !arge tracer particles (300 µm), helium-filled soap bubbles (HFSBs), is crucial and yields high particle image quality over large-volume depths when illuminated with arrays of pulsed high-power LEDs. The experimental limitations of the HFSBs-their limited lifetime and their intensity loss over time-are quantified. The HFSBs' uniform particle images allows an accurate reconstruction of the flow using Shake-The-Box particle tracking with high partlcle concentrations up to 0.1 particles per pixel. This enables tracking of up to 275,000 HFSBs simultaneously. After interpolating the scattered data onto a regular grid with a Navier-Stokes regularization, the velocity field of the thermal plume reveals a multitude of vortices with a smooth temporal evolution and a remarkable coherence in time (see animation, supplementary data). Acceleration fields are also derived from interpolated particle tracks and complement the flow measurement. Additionally, the flow map, the basis of a !arge dass of Lagrangian coherent structures, is computed directly from observed particle tracks. We show entrainment regions and coherent vortices of the thermal plume in the flow map and compute fields of the finite-time Lyapunov exponent.
elib-URL des Eintrags: | https://elib.dlr.de/116880/ | ||||||||||||||||||||||||||||
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Dokumentart: | Zeitschriftenbeitrag | ||||||||||||||||||||||||||||
Zusätzliche Informationen: | ISSN 1432-1114 (Online); Published online: 03. August 2017; Vol.: 58, lssue 9, Sept. 2017, Article 116, Publisher: Springer Berlin Heidelberg | ||||||||||||||||||||||||||||
Titel: | Large-scale volumetric flow measurement in a pure thermal plume by dense tracking of helium-filled soap bubbles | ||||||||||||||||||||||||||||
Autoren: |
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Datum: | 3 August 2017 | ||||||||||||||||||||||||||||
Erschienen in: | Experiments in Fluids | ||||||||||||||||||||||||||||
Referierte Publikation: | Ja | ||||||||||||||||||||||||||||
Open Access: | Ja | ||||||||||||||||||||||||||||
Gold Open Access: | Nein | ||||||||||||||||||||||||||||
In SCOPUS: | Ja | ||||||||||||||||||||||||||||
In ISI Web of Science: | Ja | ||||||||||||||||||||||||||||
Band: | 58 | ||||||||||||||||||||||||||||
DOI: | 10.1007/s00348-017-2390-2 | ||||||||||||||||||||||||||||
Seitenbereich: | Seiten 1-19 | ||||||||||||||||||||||||||||
Herausgeber: |
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Verlag: | Springer Nature | ||||||||||||||||||||||||||||
ISSN: | 0723-4864 | ||||||||||||||||||||||||||||
Status: | veröffentlicht | ||||||||||||||||||||||||||||
Stichwörter: | Shake-The-Box, thermal plume, helium-filled soap bubbles, Lagrangian particle tracking | ||||||||||||||||||||||||||||
HGF - Forschungsbereich: | Luftfahrt, Raumfahrt und Verkehr | ||||||||||||||||||||||||||||
HGF - Programm: | Luftfahrt | ||||||||||||||||||||||||||||
HGF - Programmthema: | Flugzeuge | ||||||||||||||||||||||||||||
DLR - Schwerpunkt: | Luftfahrt | ||||||||||||||||||||||||||||
DLR - Forschungsgebiet: | L AR - Aircraft Research | ||||||||||||||||||||||||||||
DLR - Teilgebiet (Projekt, Vorhaben): | L - Simulation und Validierung (alt) | ||||||||||||||||||||||||||||
Standort: | Göttingen | ||||||||||||||||||||||||||||
Institute & Einrichtungen: | Institut für Aerodynamik und Strömungstechnik > Experimentelle Verfahren, GO | ||||||||||||||||||||||||||||
Hinterlegt von: | Bachmann, Barbara | ||||||||||||||||||||||||||||
Hinterlegt am: | 13 Dez 2017 14:34 | ||||||||||||||||||||||||||||
Letzte Änderung: | 02 Nov 2023 13:30 |
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