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Background‑oriented schlieren imaging of flow around a circular cylinder at low Mach numbers

Stadler, Hannes and Bauknecht, Andre and Siegrist, Silvan and Flesch, Robert and Wolf, Christian C. and van Hinsberg, Nils and Jacobs, Markus (2017) Background‑oriented schlieren imaging of flow around a circular cylinder at low Mach numbers. Experiments in Fluids. Springer. DOI: 10.1007/s00348-017-2398-7 ISSN 0723-4864

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Abstract

The background-oriented schlieren (BOS) imaging method has, for the first time, been applied in the investigation of the flow around a circular cylinder at low Mach numbers (M < 0.1). The measurements were conducted in the high pressure wind tunnel, Göttingen, with static pressures ranging from 0.1 MPa to 6.0 MPa and covered a range of the Reynolds numbers of 0.1 × 106 ≤ Re ≤ 6.0 × 106. Even at ambient pressure and the lowest Reynolds number investigated, density gradients associated with the flow around the cylinder were recorded. The signal-to-noise ratio of the evaluated gradient field improved with increasing stagnation pressure. The Separation point could easily be identified with this non-intrusive measurement technique and corresponds well to simultaneous surface pressure measurements. The resulting displacement field is in principle of qualitative nature as the observation angle was parallel to the cylinder axis only in a single point of the recorded images. However, it has been possible to integrate the density field along the surface of the cylinder by successive imaging at incremental angular positions around the cylinder. This density distribution has been found to agree well with the pressure measurements and with potential theory where appropriate.

Item URL in elib:https://elib.dlr.de/113959/
Document Type:Article
Title:Background‑oriented schlieren imaging of flow around a circular cylinder at low Mach numbers
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Stadler, HannesHannes.Stadler (at) dlr.deUNSPECIFIED
Bauknecht, AndreAndre.Bauknecht (at) dlr.dehttps://orcid.org/0000-0002-4076-780X
Siegrist, SilvanSilvan.Siegrist (at) dlr.dehttps://orcid.org/0000-0001-9069-2220
Flesch, RobertRobert.Flesch (at) dlr.deUNSPECIFIED
Wolf, Christian C.christian.wolf (at) dlr.deUNSPECIFIED
van Hinsberg, NilsNils.vanHinsberg (at) dlr.deUNSPECIFIED
Jacobs, MarkusdnwUNSPECIFIED
Date:April 2017
Journal or Publication Title:Experiments in Fluids
Refereed publication:Yes
In SCOPUS:Yes
In ISI Web of Science:Yes
DOI :10.1007/s00348-017-2398-7
Publisher:Springer
ISSN:0723-4864
Status:Published
Keywords:BOS, Windkanal, Zylinder
HGF - Research field:Energy
HGF - Program:Renewable Energies
HGF - Program Themes:Concentrating Solar Thermal Technology
DLR - Research area:Energy
DLR - Program:E SW - Solar and Wind Energy
DLR - Research theme (Project):E - Advanced Heat Transfer Media
Location: Jülich
Institutes and Institutions:Institute of Solar Research > Punktfokussierende Systeme
Institute for Aerodynamics and Flow Technology > Helicopter, GO
Institute of Aeroelasticity > Aeroelastic Experiments
German-Dutch Windtunnels
Deposited By: Uhlig, Tamara
Deposited On:19 Sep 2017 14:59
Last Modified:01 Dec 2018 19:53

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