Flow structure in compound open-channel flows in the presence of transverse currents

Sébastien Proust* (Corresponding Author), Vladimir Nikora

*Corresponding author for this work

Research output: Contribution to journalConference article

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Abstract

The structure of free-surface flows is experimentally investigated in a laboratory flume with a compound cross-section consisting of a central main channel (MC) and two adjacent floodplains (FPs). The study focuses on the effects of transverse currents on: (i) mixing layers and quasi-two-dimensional coherent structures at the interfaces between MC and FPs; (ii) secondary currents developing across the channel; and (iii) large and very-large-scale motions that were recently observed in non-compound open channel flows. Transverse currents represent spanwise depth- and time-averaged flow from MC to FPs or vice versa. The study is based on one-point and two-point ADV measurements. Streamwise non-uniform flows are generated by imposing an imbalance in the discharge distribution between MC and FPs at the flume entrance, keeping the total flow rate the same for all scenarios. It is shown that even small transverse currents can be very effective in flow modification, as they can significantly displace the mixing layer, shear-layer turbulence, and coherent structures towards MC or FP, depending on the current direction. They can also alter the distribution and strength of the secondary currents. The interactions of quasi-two-dimensional coherent structures, very-large-scale motions, and secondary currents at different conditions are also part of this study.

Original languageEnglish
Article number05024
Number of pages8
JournalE3S Web of Conferences
Volume40
DOIs
Publication statusPublished - 5 Sep 2018
Event9th International Conference on Fluvial Hydraulics, River Flow 2018 - Lyon-Villeurbanne, France
Duration: 5 Sep 20188 Sep 2018

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Open channel flow
open channel flow
flow structure
Flow structure
floodplain
Turbulence
Flow rate
free surface flow
cross section
turbulence
Direction compound

ASJC Scopus subject areas

  • Environmental Science(all)
  • Energy(all)
  • Earth and Planetary Sciences(all)

Cite this

Flow structure in compound open-channel flows in the presence of transverse currents. / Proust, Sébastien (Corresponding Author); Nikora, Vladimir.

In: E3S Web of Conferences, Vol. 40, 05024, 05.09.2018.

Research output: Contribution to journalConference article

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