Effects of leading edge geometry on the vortex shedding frequency of an elongated bluff body at high Reynolds numbers

Zachary J. Taylor; Roi Gurka; Gregory A. Kopp

doi:10.1016/j.jweia.2014.03.007

Effects of leading edge geometry on the vortex shedding frequency of an elongated bluff body at high Reynolds numbers

Zachary J. Taylor, Roi Gurka, Gregory A. Kopp

Research output: Contribution to journal › Article › peer-review

40 Scopus citations

Abstract

Measurements have been performed in a large scale wind tunnel on an elongated bluff body with a chord-to-thickness ratio of 7 over the Reynolds number range Re=4.0-7.5×10⁴. Six different leading edge separation angles were created by altering the leading edge geometry. Time-resolved, synchronized, surface pressure and Particle Image Velocimetry data allow for detailed characterization of the flow around the body and in the recirculation region. The results show a linear decrease in the shedding frequency of nearly 40% as the leading edge separation angle is increased from 0°-90°. The PIV data are phase averaged in the recirculation region and the convection speed of the vortices is characterized. From the phase averaged data, the velocity outside of the recirculation region is observed to decrease markedly as the leading edge separation angle is increased, which is suggested to be responsible for the observed changes in the shedding frequency.

Original language	English
Pages (from-to)	66-75
Number of pages	10
Journal	Journal of Wind Engineering and Industrial Aerodynamics
Volume	128
DOIs	https://doi.org/10.1016/j.jweia.2014.03.007
State	Published - 1 Jan 2014
Externally published	Yes

Keywords

Bridge aerodynamics
Elongated bluff bodies
Particle image velocimetry
Separation-reattachment
Vortex shedding

ASJC Scopus subject areas

Civil and Structural Engineering
Renewable Energy, Sustainability and the Environment
Mechanical Engineering

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10.1016/j.jweia.2014.03.007

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title = "Effects of leading edge geometry on the vortex shedding frequency of an elongated bluff body at high Reynolds numbers",

abstract = "Measurements have been performed in a large scale wind tunnel on an elongated bluff body with a chord-to-thickness ratio of 7 over the Reynolds number range Re=4.0-7.5×104. Six different leading edge separation angles were created by altering the leading edge geometry. Time-resolved, synchronized, surface pressure and Particle Image Velocimetry data allow for detailed characterization of the flow around the body and in the recirculation region. The results show a linear decrease in the shedding frequency of nearly 40% as the leading edge separation angle is increased from 0°-90°. The PIV data are phase averaged in the recirculation region and the convection speed of the vortices is characterized. From the phase averaged data, the velocity outside of the recirculation region is observed to decrease markedly as the leading edge separation angle is increased, which is suggested to be responsible for the observed changes in the shedding frequency.",

keywords = "Bridge aerodynamics, Elongated bluff bodies, Particle image velocimetry, Separation-reattachment, Vortex shedding",

author = "Taylor, {Zachary J.} and Roi Gurka and Kopp, {Gregory A.}",

note = "Funding Information: This research was funded by the Natural Science and Engineering Research Council of Canada , under the Discovery Grants program. Z.J. Taylor gratefully acknowledges the support of an NSERC Postgraduate Scholarship. The authors are also indebted to Dr. Partha Sarathi, Mr. Nicolas Pratt, Ms. Sarah Stenabaugh and Mr. Gerry Dafoe for their assistance during the experiments.",

year = "2014",

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day = "1",

doi = "10.1016/j.jweia.2014.03.007",

language = "English",

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journal = "Journal of Wind Engineering and Industrial Aerodynamics",

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T1 - Effects of leading edge geometry on the vortex shedding frequency of an elongated bluff body at high Reynolds numbers

AU - Taylor, Zachary J.

AU - Gurka, Roi

AU - Kopp, Gregory A.

N1 - Funding Information: This research was funded by the Natural Science and Engineering Research Council of Canada , under the Discovery Grants program. Z.J. Taylor gratefully acknowledges the support of an NSERC Postgraduate Scholarship. The authors are also indebted to Dr. Partha Sarathi, Mr. Nicolas Pratt, Ms. Sarah Stenabaugh and Mr. Gerry Dafoe for their assistance during the experiments.

PY - 2014/1/1

Y1 - 2014/1/1

N2 - Measurements have been performed in a large scale wind tunnel on an elongated bluff body with a chord-to-thickness ratio of 7 over the Reynolds number range Re=4.0-7.5×104. Six different leading edge separation angles were created by altering the leading edge geometry. Time-resolved, synchronized, surface pressure and Particle Image Velocimetry data allow for detailed characterization of the flow around the body and in the recirculation region. The results show a linear decrease in the shedding frequency of nearly 40% as the leading edge separation angle is increased from 0°-90°. The PIV data are phase averaged in the recirculation region and the convection speed of the vortices is characterized. From the phase averaged data, the velocity outside of the recirculation region is observed to decrease markedly as the leading edge separation angle is increased, which is suggested to be responsible for the observed changes in the shedding frequency.

AB - Measurements have been performed in a large scale wind tunnel on an elongated bluff body with a chord-to-thickness ratio of 7 over the Reynolds number range Re=4.0-7.5×104. Six different leading edge separation angles were created by altering the leading edge geometry. Time-resolved, synchronized, surface pressure and Particle Image Velocimetry data allow for detailed characterization of the flow around the body and in the recirculation region. The results show a linear decrease in the shedding frequency of nearly 40% as the leading edge separation angle is increased from 0°-90°. The PIV data are phase averaged in the recirculation region and the convection speed of the vortices is characterized. From the phase averaged data, the velocity outside of the recirculation region is observed to decrease markedly as the leading edge separation angle is increased, which is suggested to be responsible for the observed changes in the shedding frequency.

KW - Bridge aerodynamics

KW - Elongated bluff bodies

KW - Particle image velocimetry

KW - Separation-reattachment

KW - Vortex shedding

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SN - 0167-6105

VL - 128

SP - 66

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JO - Journal of Wind Engineering and Industrial Aerodynamics

JF - Journal of Wind Engineering and Industrial Aerodynamics

ER -

Effects of leading edge geometry on the vortex shedding frequency of an elongated bluff body at high Reynolds numbers

Abstract

Keywords

ASJC Scopus subject areas

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