Author(s): K. Vastila; J. Jarvela; J. Aberle; T. Schoneboom
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Keywords: Vegetation; Foliage; Flow resistance; Drag force; Reconfiguration
Abstract: Reliable estimation of vegetative flow resistance requires basing the estimates on physically sound and readily measurable plant properties. This paper investigates the relationship between drag and physical properties of natural, foliated Black poplars. Drag forces exerted on poplars in an array were measured simultaneously using up to ten force sensors in a laboratory flume. Frontal projected area was photographed under flow action. Leaves contributed almost 90% to the total drag. The onesided leaf area (AL) and the leaf area to the stem area ratio (A L/A S) influenced the detected variability in the drag force. The poplars had a higher AL/A S ratio and thus a greater ability to reconfiguration and drag reduction than previously reported for other species. The findings supported the hypothesis that such objectively defined and readily measurable reference area definitions could be used in estimating friction factors for foliated vegetation.
Year: 2011