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 : Coherent structure and particle turbulence interaction in suspended sediment-laden laboratory open-c...
Coherent structure and particle turbulence interaction in suspended sediment-laden laboratory open-channel flows
Author : Fereshteh Bagherimiyab
In order to simulate fine sediment dynamics over an armored bed in a river during the passage of a flood wave, quasi-instantaneous profiles of velocity and sediment concentration were taken simultaneously and co-located using acoustic Doppler and imaging methods. Flow visualization and PTV measurements were made in parallel. Systematically higher friction velocities were observed in accelerating flow than in decelerating flow for comparable mean flow velocities. This indicates that the same change of relative submergence generates different flow dynamics in both flow ranges. In the final phase of the accelerating flow range, fine sediment suspension from the bed started in bursts and rapidly created nearly stationary ripples. Vortices shedding from the ripple crests produced most of the sediment suspension in the form of events, making suspension intermittent. Due to the ripple structure, high sediment suspension continued to occur during the decelerating flow even though the flow velocity decreased.
File Size : 595,874 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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