IAHR, founded in 1935, is a worldwide independent member-based organisation of engineers and water specialists working in fields related to the hydro-environmental sciences and their practical application. Activities range from river and maritime hydraulics to water resources development and eco-hydraulics, through to ice engineering, hydroinformatics, and hydraulic machinery.
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You are here : eLibrary : IAHR World Congress Proceedings : 34th Congress - Brisbane (2011) : THEME 5: Environmental Hydraulics and Hydrology : Refining parameterization of bar vegetation roughness based on in-situ-measurements of vegetation be...
Refining parameterization of bar vegetation roughness based on in-situ-measurements of vegetation bending during flood events
Author : B. Blamauer1, M. Klösch1, M. Tritthart1 and H. Habersack1
For modelling erosion and sedimentation processes in rivers with vegetated bars detailed knowledge of the interactions between flow and vegetation is needed. Earlier studies showed that flexible vegetation significantly influences the flow by altering the roughness coefficient and velocity distribution, with the vegetation bending as a crucial factor. So far investigations were mostly limited to flume experiments, at the Drau River vegetation bending was measured in-situ during floods by using a time-lapse camera and applying photogrammetric techniques. Parameters like stem diameters and projected area were determined from willows and tamarisks. Together with data from literature, they were used in a 2-D hydrodynamic-numerical model which included an improved drag force approach to calculate variable roughness coefficients of flexible vegetation. Observed and calculated bending angles were compared for further model adjustment. Variations of parameters showed to strongly affect the calculated bending and the modelled flow field on a vegetated bar.
File Size : 761,905 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 34th Congress - Brisbane (2011)
Article : THEME 5: Environmental Hydraulics and Hydrology
Date Published : 01/07/2011
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