Is the von Krmn constant affected by sediment suspension?
Is the von Krmn constant affected by sediment suspension? The presence of suspended sediment in channels and fluvial streams has been known for decades to affect turbulence transfer mechanism in sediment-laden flows, and, therefore, the transport and fate of sediments that determine the bathymetry of natural water courses. This study explores the density stratification effects on the turbulent velocity profile and its impact on the transport of sediment. There is as yet no consensus in the scientific community on the effect of sediment suspension on the von Krmn parameter, . Two different theories based on the empirical log-wake velocity profile are currently under debate: One supports a universal value of =0.41 and a strength of the wake, , that is affected by suspended sediment. The other suggests that both and could vary with suspended sediment. These different theories result in a conceptual problem regarding the effect of suspended sediment on , which has divided the research area. In this study, a new mixing length theory is proposed to describe theoretically the turbulent velocity profile. The analytical approach provides added insight defining as a turbulent parameter which varies with the distance to the bed in sediment-laden flows. The theory is compared with previous experimental data and simulations using a k-turbulence closure to the Reynolds averaged Navier Stokes equations model. The mixing length model indicates that the two contradictory theories incorporate the stratified flow effect into a different component of the log-wake law. The results of this work show that the log-wake fit with a reduced is the physically coherent approximation. © 2012. American Geophysical Union. All Rights Reserved.
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Format: | artículo biblioteca |
Language: | English |
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William Byrd Press for Johns Hopkins Press
2012-12
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Subjects: | Open channel flow, Sediment suspensions, Steady flow, Turbulent flow, Velocity profile, |
Online Access: | http://hdl.handle.net/10261/89357 |
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dig-ias-es-10261-893572018-08-02T12:10:10Z Is the von Krmn constant affected by sediment suspension? Castro-Orgaz, Óscar Giráldez, Juan Vicente Mateos, Luciano Dey, Subhasish Open channel flow Sediment suspensions Steady flow Turbulent flow Velocity profile Is the von Krmn constant affected by sediment suspension? The presence of suspended sediment in channels and fluvial streams has been known for decades to affect turbulence transfer mechanism in sediment-laden flows, and, therefore, the transport and fate of sediments that determine the bathymetry of natural water courses. This study explores the density stratification effects on the turbulent velocity profile and its impact on the transport of sediment. There is as yet no consensus in the scientific community on the effect of sediment suspension on the von Krmn parameter, . Two different theories based on the empirical log-wake velocity profile are currently under debate: One supports a universal value of =0.41 and a strength of the wake, , that is affected by suspended sediment. The other suggests that both and could vary with suspended sediment. These different theories result in a conceptual problem regarding the effect of suspended sediment on , which has divided the research area. In this study, a new mixing length theory is proposed to describe theoretically the turbulent velocity profile. The analytical approach provides added insight defining as a turbulent parameter which varies with the distance to the bed in sediment-laden flows. The theory is compared with previous experimental data and simulations using a k-turbulence closure to the Reynolds averaged Navier Stokes equations model. The mixing length model indicates that the two contradictory theories incorporate the stratified flow effect into a different component of the log-wake law. The results of this work show that the log-wake fit with a reduced is the physically coherent approximation. © 2012. American Geophysical Union. All Rights Reserved. This research was partially funded by the project P08-AGR-03925 (Junta de Andalucía). Peer Reviewed 2014-01-14T08:54:38Z 2014-01-14T08:54:38Z 2012-12 2014-01-14T08:54:38Z artículo http://purl.org/coar/resource_type/c_6501 doi: 10.1029/2011JF002211 issn: 0148-0227 e-issn: 2156-2202 Journal of Geophysical Research 117(F4): (2012) http://hdl.handle.net/10261/89357 10.1029/2011JF002211 en http://dx.doi.org/10.1029/2011JF002211 open William Byrd Press for Johns Hopkins Press |
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Open channel flow Sediment suspensions Steady flow Turbulent flow Velocity profile Open channel flow Sediment suspensions Steady flow Turbulent flow Velocity profile |
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Open channel flow Sediment suspensions Steady flow Turbulent flow Velocity profile Open channel flow Sediment suspensions Steady flow Turbulent flow Velocity profile Castro-Orgaz, Óscar Giráldez, Juan Vicente Mateos, Luciano Dey, Subhasish Is the von Krmn constant affected by sediment suspension? |
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Is the von Krmn constant affected by sediment suspension? The presence of suspended sediment in channels and fluvial streams has been known for decades to affect turbulence transfer mechanism in sediment-laden flows, and, therefore, the transport and fate of sediments that determine the bathymetry of natural water courses. This study explores the density stratification effects on the turbulent velocity profile and its impact on the transport of sediment. There is as yet no consensus in the scientific community on the effect of sediment suspension on the von Krmn parameter, . Two different theories based on the empirical log-wake velocity profile are currently under debate: One supports a universal value of =0.41 and a strength of the wake, , that is affected by suspended sediment. The other suggests that both and could vary with suspended sediment. These different theories result in a conceptual problem regarding the effect of suspended sediment on , which has divided the research area. In this study, a new mixing length theory is proposed to describe theoretically the turbulent velocity profile. The analytical approach provides added insight defining as a turbulent parameter which varies with the distance to the bed in sediment-laden flows. The theory is compared with previous experimental data and simulations using a k-turbulence closure to the Reynolds averaged Navier Stokes equations model. The mixing length model indicates that the two contradictory theories incorporate the stratified flow effect into a different component of the log-wake law. The results of this work show that the log-wake fit with a reduced is the physically coherent approximation. © 2012. American Geophysical Union. All Rights Reserved. |
format |
artículo |
topic_facet |
Open channel flow Sediment suspensions Steady flow Turbulent flow Velocity profile |
author |
Castro-Orgaz, Óscar Giráldez, Juan Vicente Mateos, Luciano Dey, Subhasish |
author_facet |
Castro-Orgaz, Óscar Giráldez, Juan Vicente Mateos, Luciano Dey, Subhasish |
author_sort |
Castro-Orgaz, Óscar |
title |
Is the von Krmn constant affected by sediment suspension? |
title_short |
Is the von Krmn constant affected by sediment suspension? |
title_full |
Is the von Krmn constant affected by sediment suspension? |
title_fullStr |
Is the von Krmn constant affected by sediment suspension? |
title_full_unstemmed |
Is the von Krmn constant affected by sediment suspension? |
title_sort |
is the von krmn constant affected by sediment suspension? |
publisher |
William Byrd Press for Johns Hopkins Press |
publishDate |
2012-12 |
url |
http://hdl.handle.net/10261/89357 |
work_keys_str_mv |
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