Measuring Aerodynamic Interference Drag Between a Bird Body and the Mounting Strut of a drag Balance
1. The drag of a bird body mounted on the strut of a drag balance in a wind tunnel is more than the sum of the drags of the isolated strut and the isolated body. The strut changes the air flow around the body and generates additional drag, known as interference drag. This paper describes practical m...
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fthighwire:oai:open-archive.highwire.org:jexbio:154/1/439 2023-05-15T16:10:02+02:00 Measuring Aerodynamic Interference Drag Between a Bird Body and the Mounting Strut of a drag Balance TUCKER, VANCE A. 1990-11-01 00:00:00.0 text/html http://jeb.biologists.org/cgi/content/short/154/1/439 en eng Company of Biologists http://jeb.biologists.org/cgi/content/short/154/1/439 Copyright (C) 1990, Company of Biologists Journal Articles TEXT 1990 fthighwire 2013-04-02T07:29:35Z 1. The drag of a bird body mounted on the strut of a drag balance in a wind tunnel is more than the sum of the drags of the isolated strut and the isolated body. The strut changes the air flow around the body and generates additional drag, known as interference drag. This paper describes practical methods for measuring the drag of bird bodies: a strain-gauge drag balance, dimensions for struts made with machine or hand tools, and a procedure for correcting drag measurements for interference drag. 2. Interference drag can be measured by extrapolating a relationship between the drag of isolated struts with different crosssectional sizes and shapes and the drag of a body mounted on those struts. The interference length the length of an isolated strut that produces drag equal to the interference drag is a usefulquantity for predicting interference drag. 3. The relationship mentioned above is a straight line for a model peregrine falcon ( Falco peregrinus L.) body mounted on smooth struts struts with convex cross-sectional shapes ranging from streamlined to circular. This finding simplifies the determination of interference drag in three ways: (i) the line can be found from measurements with just two struts a standard strut with low drag and a calibration strut with high drag; (ii) the two struts need not have the same shape for example, the standard strut can be changed to a calibration strut by attaching a spoiler without disturbing the body mounted on the strut and (iii) a single value of interference length (33.1mm) describes smooth struts with a range of shapes and sizes. These struts had drag coefficients between 0.33 and 0.91 at Reynolds numbers between 2100 and 10800. 4. The interference length of a strut supporting the actual falcon body with a feathered surface is not significantly different from that of the strut supporting the model body with a rigid surface. 5. As a hypothesis, interference length (h I , in metres) of a smooth strut varieswith the size of the body mounted on it: h I =0.0365m0.333 where m ... Text Falco peregrinus peregrine falcon HighWire Press (Stanford University) |
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English |
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Journal Articles |
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Journal Articles TUCKER, VANCE A. Measuring Aerodynamic Interference Drag Between a Bird Body and the Mounting Strut of a drag Balance |
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Journal Articles |
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1. The drag of a bird body mounted on the strut of a drag balance in a wind tunnel is more than the sum of the drags of the isolated strut and the isolated body. The strut changes the air flow around the body and generates additional drag, known as interference drag. This paper describes practical methods for measuring the drag of bird bodies: a strain-gauge drag balance, dimensions for struts made with machine or hand tools, and a procedure for correcting drag measurements for interference drag. 2. Interference drag can be measured by extrapolating a relationship between the drag of isolated struts with different crosssectional sizes and shapes and the drag of a body mounted on those struts. The interference length the length of an isolated strut that produces drag equal to the interference drag is a usefulquantity for predicting interference drag. 3. The relationship mentioned above is a straight line for a model peregrine falcon ( Falco peregrinus L.) body mounted on smooth struts struts with convex cross-sectional shapes ranging from streamlined to circular. This finding simplifies the determination of interference drag in three ways: (i) the line can be found from measurements with just two struts a standard strut with low drag and a calibration strut with high drag; (ii) the two struts need not have the same shape for example, the standard strut can be changed to a calibration strut by attaching a spoiler without disturbing the body mounted on the strut and (iii) a single value of interference length (33.1mm) describes smooth struts with a range of shapes and sizes. These struts had drag coefficients between 0.33 and 0.91 at Reynolds numbers between 2100 and 10800. 4. The interference length of a strut supporting the actual falcon body with a feathered surface is not significantly different from that of the strut supporting the model body with a rigid surface. 5. As a hypothesis, interference length (h I , in metres) of a smooth strut varieswith the size of the body mounted on it: h I =0.0365m0.333 where m ... |
format |
Text |
author |
TUCKER, VANCE A. |
author_facet |
TUCKER, VANCE A. |
author_sort |
TUCKER, VANCE A. |
title |
Measuring Aerodynamic Interference Drag Between a Bird Body and the Mounting Strut of a drag Balance |
title_short |
Measuring Aerodynamic Interference Drag Between a Bird Body and the Mounting Strut of a drag Balance |
title_full |
Measuring Aerodynamic Interference Drag Between a Bird Body and the Mounting Strut of a drag Balance |
title_fullStr |
Measuring Aerodynamic Interference Drag Between a Bird Body and the Mounting Strut of a drag Balance |
title_full_unstemmed |
Measuring Aerodynamic Interference Drag Between a Bird Body and the Mounting Strut of a drag Balance |
title_sort |
measuring aerodynamic interference drag between a bird body and the mounting strut of a drag balance |
publisher |
Company of Biologists |
publishDate |
1990 |
url |
http://jeb.biologists.org/cgi/content/short/154/1/439 |
genre |
Falco peregrinus peregrine falcon |
genre_facet |
Falco peregrinus peregrine falcon |
op_relation |
http://jeb.biologists.org/cgi/content/short/154/1/439 |
op_rights |
Copyright (C) 1990, Company of Biologists |
_version_ |
1765995285948923904 |