Impact of Foliage on the Drag Force of Vegetation in Aquatic Flows
Publication: Journal of Hydraulic Engineering
Volume 134, Issue 7
Abstract
The objective of this study was to determine the contribution of a plant’s foliage to the total plant’s hydrodynamic drag. Experiments were conducted in a laboratory flume using samples of vegetation with different physical forms and biomechanical properties: Branches of pine (Pinus sylvestris) and ivy stipes (Glechoma hederacea). The drag force was measured directly using a strain gauge technique and determined for a series of velocities for each vegetation species with and without foliage. Experimental results revealed a distinct contribution of foliage to the total plant drag. For both plant types, this was particularly marked at lower velocities where the foliage is not streamlined and compressed and, hence, the frontal projected area of the plant is at a maximum. It was found that the flexibility of the plant’s foliage and its ability to streamline with the flow may reduce the overall drag considerably. There was a distinct difference in the parameter-velocity squared relationship between the “with” foliage plants and nonfoliage counterparts due to the streamlining effect of the foliage with the flow and, hence, the reduction in overall drag associated with the new compressed plant form.
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Acknowledgments
C. A. M. E. Wilson was aided by the Engineering and Physical Science Research Council (EPSRC) of the U.K. on an Advanced Research Fellowship Grant No. EPSRC-GBGR/A11239/01. The writers are grateful to Julien Mas who assisted in the preliminary tests. Finally, thanks to the reviewers for providing constructive and thoughtful comments.
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Information & Authors
Information
Published In
Journal of Hydraulic Engineering
Volume 134 • Issue 7 • July 2008
Pages: 885 - 891
Copyright
© 2008 ASCE.
History
Received: Jun 6, 2006
Accepted: Oct 9, 2007
Published online: Jul 1, 2008
Published in print: Jul 2008
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