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Reynolds-number-effects in flow around a rectangular cylinder with aspect ratio 1:5

Schewe, Günter (2013) Reynolds-number-effects in flow around a rectangular cylinder with aspect ratio 1:5. Journal of Fluids and Structures, 39, pp. 15-26. Elsevier. DOI: 10.1016/j.jfluidstructs.2013.02.013 ISSN 0889-9746

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Official URL: http://dx.doi.org/10.1016/j.jfluidstructs.2013.02.013

Abstract

The paper reports on experiments carried out over a wide range of Reynolds numbers in a high pressure wind tunnel. The model was a sharp-edged rectangular cylinder with aspect ratio height/width 1:5 (width/span ratio 1:10.8), which was investigated in both basic orientations, lengthwise (4×103<Re<4×105) and perpendicular to the flow (2.7×104<Re<6.4×105). The Reynolds number is based on the height of the model normal to the flow. Steady and unsteady forces were measured with a piezoelectric balance. Thus along with steady (i.e. time averaged values) including the base pressure coefficient, also power spectra and probability density functions were measured yielding for example Strouhal numbers, higher statistical moments, etc. A response diagram for the vortex resonance phenomenon was taken for the natural bending motion of the slender model. If lift coefficient for constant angle of attack is plotted against Reynolds number, a significant Reynolds number effect is seen. For α=4°, the curve shows an inflection point and the lift varies between 0.3 and 0.6. For α=6° and 2° there are similar variations shifted to lower and higher values of Re, respectively. Probably the shapes of separation bubbles that depend on the Reynolds number are responsible for these effects. No Reynolds number effects were observed when the long side was normal to the flow, an orientation where reattachment at the side walls is not possible. Comparing both basic cases (α=0° and 90°), the interpretation of the probability distributions of lift force leads to the conclusion that the possibility of reattachment (α=0°) seems to enhance the degree of order in the vortex shedding process.

Item URL in elib:https://elib.dlr.de/84214/
Document Type:Article
Title:Reynolds-number-effects in flow around a rectangular cylinder with aspect ratio 1:5
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Schewe, Günterguenter.schewe (at) dlr.deUNSPECIFIED
Date:18 March 2013
Journal or Publication Title:Journal of Fluids and Structures
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:39
DOI :10.1016/j.jfluidstructs.2013.02.013
Page Range:pp. 15-26
Publisher:Elsevier
ISSN:0889-9746
Status:Published
Keywords:Reynolds number, Bluff body, Rectangular cylinder, Flow separation, Vortex resonance
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 - Flight Physics (old)
Location: Göttingen
Institutes and Institutions:Institute of Aeroelasticity > Aeroelastic Experiments
Deposited By: Mai, Holger
Deposited On:25 Sep 2013 11:14
Last Modified:09 Jan 2014 10:33

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