E3S Web Conf.
Volume 40, 2018River Flow 2018 - Ninth International Conference on Fluvial Hydraulics
|Number of page(s)||8|
|Section||Sediment and pollutant dynamics in rivers|
|Published online||05 September 2018|
On bedload measurement performances of high-resolution acoustic (ACVP) and conductivity (CCP) profilers
Laboratory of Geophysical and Industrial Flow, 38041 Grenoble Cedex 9, France
2 Centre for Applied Coastal Research, University of Delaware, Newark, DE, USA
* Corresponding author: email@example.com
Intense sediment transport experiments were performed in a gravity driven open-channel flow with two sizes of non-spherical acrylic particles of diameter dp=1.0mm and dp=3.0 mm, and a maximum packing volumetric concentration of 0.55 m3/m3. Two flow conditions were adapted to ensure the same sediment transport regime for particle sizes as sheet flows (Shields numbers above unity) with an equi-repartition of the total net sediment transport rate between the suspended load and the bedload (Suspension number around unity). An acoustic scattering-based system, the Acoustic Concentration and Velocity Profiler (ACVP) and electric conductivity probes, the Conductivity Concentration Profiler (CCP) with two different vertical resolutions of 1mm (CCP1mm) and 2 mm (CCP2mm),were used to measure time-resolved and averaged concentration profiles across the bed-load and suspension layers. A detailed comparative analysis of concentration and sheet flow layer thickness measurements obtained with the two systems across both the suspension and the bedload layers is presented. The capabilities and limitations of the two flow measurement technologies are outlined. Average sediment concentration profiles were overestimated by 10% with the ACVP in the dense sheet layer when ⟨φ(z)⟩ ≳ 0.35, and by 100% with the CCP in the more diluted region when ⟨φ(z)⟩ ≲ 0.015 and ⟨φ(z)⟩ ≲ 0.20 for CCP1mm and CCP2mm, respectively. Good agreement is found elsewhere between the three systems in terms of average and time-resolved concentration as well as bed level position and sheet flow layer thickness.
© The Authors, published by EDP Sciences, 2018
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (http://creativecommons.org/licenses/by/4.0/).
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