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Investigation of the steady and unsteady forces acting on a pair of circular cylinders in crossflow up to ultra-high Reynolds numbers

Schewe, Günter and van Hinsberg, Nils and Jacobs, Markus (2021) Investigation of the steady and unsteady forces acting on a pair of circular cylinders in crossflow up to ultra-high Reynolds numbers. Experiments in Fluids, 62 (176), pp. 1-18. Springer. doi: 10.1007/s00348-021-03268-7. ISSN 0723-4864.

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Official URL: https://www.springerprofessional.de/investigation-of-the-steady-and-unsteady-forces-acting-on-a-pair/19404096?fulltextView=true

Abstract

Measurements of the steady and unsteady forces acting on a pair of circular cylinders in crossflow are performed from subcritical up to ultra-high Reynolds numbers. The two cylinders with equal diameters d are arranged inline at two centre-to-centre distances: S/d = 2.8 and 4. The trend of the drag curve for the upstream cylinder Cd1(Re) at both distances is similar to that for a single circular cylinder. The development of the drag curves Cd2(Re, S/d = 2.8, 4) of the downstream cylinder is inverse to that of the upstream cylinder. For both cylinder spacing values, the drag on the downstream cylinder is negative for subcritical Reynolds numbers, increases abruptly to positive values at the beginning of the supercritical regime, and shows a significant dip at transcritical Reynolds numbers. This drag inversion indicates that the critical distance Sc decreases sharply in the supercritical Reynolds number range. For S/d = 2.8 at Re to 10E7, the downstream cylinder experiences once more a thrust force. The curve of the Strouhal number St(Re) of the downstream cylinder for S/d = 4 is very close to that of a single cylinder. For Reynolds numbers of Re = 1×10E6 - 7×10E6, the Strouhal numbers have nearly equal values of St = 0.22 - 0.24 for both distances. This is followed by a branching. For Re to 10E7 and the case S/d = 2.8, the Strouhal numbers dip at St = 0.17. However, for S/d = 4, they increase up to St = 0.27. In the supercritical range, two peaks occur in the power spectra for the large distance S/d = 4. Based on a wavelet analysis, we can conclude that the low-frequency mode, which does not occur for a single cylinder, is an interference effect.

Item URL in elib:https://elib.dlr.de/143359/
Document Type:Article
Title:Investigation of the steady and unsteady forces acting on a pair of circular cylinders in crossflow up to ultra-high Reynolds numbers
Authors:
AuthorsInstitution or Email of AuthorsAuthor's ORCID iD
Schewe, Günterguenter.schewe (at) dlr.deUNSPECIFIED
van Hinsberg, NilsNils.vanHinsberg (at) dlr.deUNSPECIFIED
Jacobs, Markusmarkus.jacobs (at) dnw.aeroUNSPECIFIED
Date:July 2021
Journal or Publication Title:Experiments in Fluids
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:62
DOI :10.1007/s00348-021-03268-7
Page Range:pp. 1-18
Publisher:Springer
ISSN:0723-4864
Status:Published
Keywords:Tandem circular cylinders, high Reynolds number, interference effects, negative drag, unsteady forces, buffeting, wavelet analysis
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:Components and Systems
DLR - Research area:Aeronautics
DLR - Program:L CS - Components and Systems
DLR - Research theme (Project):L - Aircraft Systems
Location: Göttingen
Institutes and Institutions:Institute of Aeroelasticity > Aeroelastic Experiments
Deposited By: van Hinsberg, Dr. Ir. Nils
Deposited On:26 Aug 2021 16:41
Last Modified:24 May 2022 23:47

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