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dc.contributor.author
Albayrak, Ismail
dc.contributor.author
Lemmin, Ulrich
dc.date.accessioned
2020-09-25T13:49:53Z
dc.date.available
2017-06-09T18:47:02Z
dc.date.available
2020-09-25T13:49:53Z
dc.date.issued
2011-11
dc.identifier.issn
0733-9429
dc.identifier.issn
1943-7900
dc.identifier.other
10.1061/(ASCE)HY.1943-7900.0000438
en_US
dc.identifier.uri
http://hdl.handle.net/20.500.11850/45273
dc.description.abstract
River and open-channel flows present complex three-dimensional (3D) structures in the water column and on the surface as a result of the existence of secondary currents driven by either centrifugal force or turbulence. This paper experimentally investigates secondary currents in a straight, turbulent, rough-bed open-channel flow; the effect of different channel width to flow depth ratios (12.25, 15, and 20) on secondary currents; and surface boils associated with secondary currents at moderate Reynolds numbers. Nearly instantaneous profiles of three components of flow velocity and turbulence characteristics in the water column were measured by using an acoustic Doppler velocity profiler (ADVP). Simultaneously, large-scale particle image velocimetry was used to measure the water surface velocities and turbulence structures. Mean velocity patterns in the water undulate across the channel, indicating the presence of secondary currents in the long-term average flow structure. Secondary currents affect the distribution of bed shear stress, Reynolds stress, and turbulence intensities across the channel. The aspect ratio determines the number of secondary cells in the water column. A mean multiband undulating surface velocity pattern in the transverse direction correlates with the secondary cell distribution in the water column below. The instantaneous position of the upwelling and downwelling regions on the surface may deviate from their long-term mean position, indicating a meandering of the surface pattern. Vortex structures are detected from instantaneous surface velocity maps, and vortex boil lines are identified. Boil vortices mainly occur in upwelling areas with high vorticity. The simultaneous detailed velocity measurements in the water column and on the free surface have shown a good agreement between the secondary cell patterns obtained by the two methods. © 2011 American Society of Civil Engineers.
en_US
dc.language.iso
en
en_US
dc.publisher
ASCE
en_US
dc.subject
Turbulent open-channel flow
en_US
dc.subject
Secondary currents
en_US
dc.subject
Reynolds stress
en_US
dc.subject
ADVP
en_US
dc.subject
Large-scale PIV
en_US
dc.title
Secondary Currents and Corresponding Surface Velocity Patterns in a Turbulent Open-Channel Flow over a Rough Bed
en_US
dc.type
Journal Article
dc.date.published
2011-04-13
ethz.journal.title
Journal of Hydraulic Engineering
ethz.journal.volume
137
en_US
ethz.journal.issue
11
en_US
ethz.journal.abbreviated
J. hydraul. eng.
ethz.pages.start
1318
en_US
ethz.pages.end
1334
en_US
ethz.identifier.wos
ethz.identifier.nebis
000017082
ethz.publication.place
New York
en_US
ethz.publication.status
published
en_US
ethz.date.deposited
2017-06-09T18:47:20Z
ethz.source
ECIT
ethz.identifier.importid
imp59364ee81469d28499
ethz.ecitpid
pub:74477
ethz.eth
yes
en_US
ethz.availability
Metadata only
en_US
ethz.rosetta.installDate
2017-07-13T13:13:49Z
ethz.rosetta.lastUpdated
2018-08-02T09:02:18Z
ethz.rosetta.exportRequired
true
ethz.rosetta.versionExported
true
ethz.COinS
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