Dépouillements

Joseph Boussinesq and his theory of water flow in open channels / Oscar Castro-Orgaz in Journal of hydraulic research, Vol. 49 N° 5 (Septembre/Octobre 2011) 

Public ISBD [article]  in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 569-577 Titre : Joseph Boussinesq and his theory of water flow in open channels Type de document : texte imprimé Auteurs : Oscar Castro-Orgaz, Auteur ; Willi H. Hager, Auteur Année de publication : 2011 Article en page(s) : pp. 569-577 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Backwater  curve  Curvilinear  flow  Eddy  viscosity  Free  overfall  Turbulent  flow  Undular  hydraulic  jump Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : Joseph Valentin Boussinesq (1842–1929) is known in open channel hydraulics for the outstanding theory bearing his name to deal with streamlined-flows. However, the original developments did not last over time and remain lost in his original writings. A current state of the art indicates domination of the gradually-varied flow theory in research, teaching and practice. The present Forum paper explores the original work of Boussinesq, from which it is discovered that his theory is more general than currently believed. Important findings include an original solution for the turbulent velocity profile with streamline curvature, a misleading interpretation of his famous velocity correction coefficient bearing his name, and a rigorous and systematic classification of backwater curves, including these arising from curvilinear flows. This presentation is intended to diffuse his theory to its definite inclusion in research, teaching and practice, given its superiority over current standards of gradually-varied flow computations. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.588784 [article] Joseph Boussinesq and his theory of water flow in open channels [texte imprimé] / Oscar Castro-Orgaz, Auteur ; Willi H. Hager, Auteur . - 2011 . - pp. 569-577. Hydraulique Langues : Anglais (eng) in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 569-577 Mots-clés : Backwater  curve  Curvilinear  flow  Eddy  viscosity  Free  overfall  Turbulent  flow  Undular  hydraulic  jump Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : Joseph Valentin Boussinesq (1842–1929) is known in open channel hydraulics for the outstanding theory bearing his name to deal with streamlined-flows. However, the original developments did not last over time and remain lost in his original writings. A current state of the art indicates domination of the gradually-varied flow theory in research, teaching and practice. The present Forum paper explores the original work of Boussinesq, from which it is discovered that his theory is more general than currently believed. Important findings include an original solution for the turbulent velocity profile with streamline curvature, a misleading interpretation of his famous velocity correction coefficient bearing his name, and a rigorous and systematic classification of backwater curves, including these arising from curvilinear flows. This presentation is intended to diffuse his theory to its definite inclusion in research, teaching and practice, given its superiority over current standards of gradually-varied flow computations. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.588784

Flow velocity measurement in Italy between Renaissance and Risorgimento / Mario Di Fidio in Journal of hydraulic research, Vol. 49 N° 5 (Septembre/Octobre 2011) 

Public ISBD [article]  in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 578-585 Titre : Flow velocity measurement in Italy between Renaissance and Risorgimento Type de document : texte imprimé Auteurs : Mario Di Fidio, Auteur ; Claudio Gandolfi, Auteur Année de publication : 2011 Article en page(s) : pp. 578-585 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Flow  velocity  History  Hydraulics  Velocity  meter  Velocity  distribution Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : A review of the main instruments developed in Italy over more than two centuries to measure flow velocity of experience is presented, highlighting the relation with the development of hydraulics as a physical–mathematical science from the seventeenth century. The number and variety of Italian velocity meters partly reflect the vitality of a tradition, characterized by political polycentrism and rivalry among the individual cities and universities. In other aspects, the invention of ever-newer measuring instruments corresponds to the attitude of many of the early Italian hydraulicians, who interpreted hydraulics as a science of nature, based almost exclusively on observation and experience, which requires rather the gift of intuition than mathematical deduction. This work is part of a project of the BEIC Library and of the University of Milan, which will make available digital versions of hundreds of Italian historic texts of hydraulics on the portal www.beic.it. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.594599 [article] Flow velocity measurement in Italy between Renaissance and Risorgimento [texte imprimé] / Mario Di Fidio, Auteur ; Claudio Gandolfi, Auteur . - 2011 . - pp. 578-585. Hydraulique Langues : Anglais (eng) in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 578-585 Mots-clés : Flow  velocity  History  Hydraulics  Velocity  meter  Velocity  distribution Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : A review of the main instruments developed in Italy over more than two centuries to measure flow velocity of experience is presented, highlighting the relation with the development of hydraulics as a physical–mathematical science from the seventeenth century. The number and variety of Italian velocity meters partly reflect the vitality of a tradition, characterized by political polycentrism and rivalry among the individual cities and universities. In other aspects, the invention of ever-newer measuring instruments corresponds to the attitude of many of the early Italian hydraulicians, who interpreted hydraulics as a science of nature, based almost exclusively on observation and experience, which requires rather the gift of intuition than mathematical deduction. This work is part of a project of the BEIC Library and of the University of Milan, which will make available digital versions of hundreds of Italian historic texts of hydraulics on the portal www.beic.it. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.594599

Shallow-flow visualization analysis by proper orthogonal decomposition / Wernher Brevis in Journal of hydraulic research, Vol. 49 N° 5 (Septembre/Octobre 2011) 

Public ISBD [article]  in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 586-594 Titre : Shallow-flow visualization analysis by proper orthogonal decomposition Type de document : texte imprimé Auteurs : Wernher Brevis, Auteur ; Manuel García-Villalba, Auteur Année de publication : 2011 Article en page(s) : pp. 586-594 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Coherent  structure  Cylinder  wake  Flow  visualization  POD  Shallow  flow Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : The identification of the spatial characteristics and the shedding frequencies of coherent structures in shallow flows usually involves the use of sophisticated equipment for velocity measurements such as laser Doppler anemometry or particle image velocimetry. In this work, a simple and low-cost alternative for the quantitative characterization of quasi two-dimensional shallow coherent structures is presented. The technique is based on the image pre-processing of flow visualizations and post-processing by means of the proper orthogonal decomposition. As an illustration of the method, the analysis of a shallow flow in the wake of a cylinder with a vortex-street pattern is presented. The method is able to discriminate concentration patches attached to the vortices and their advection, providing frequencies in excellent agreement with a previous study. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.585012 [article] Shallow-flow visualization analysis by proper orthogonal decomposition [texte imprimé] / Wernher Brevis, Auteur ; Manuel García-Villalba, Auteur . - 2011 . - pp. 586-594. Hydraulique Langues : Anglais (eng) in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 586-594 Mots-clés : Coherent  structure  Cylinder  wake  Flow  visualization  POD  Shallow  flow Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : The identification of the spatial characteristics and the shedding frequencies of coherent structures in shallow flows usually involves the use of sophisticated equipment for velocity measurements such as laser Doppler anemometry or particle image velocimetry. In this work, a simple and low-cost alternative for the quantitative characterization of quasi two-dimensional shallow coherent structures is presented. The technique is based on the image pre-processing of flow visualizations and post-processing by means of the proper orthogonal decomposition. As an illustration of the method, the analysis of a shallow flow in the wake of a cylinder with a vortex-street pattern is presented. The method is able to discriminate concentration patches attached to the vortices and their advection, providing frequencies in excellent agreement with a previous study. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.585012

A numerical study of confined wall jets in a shallow basin / Islam Mohammed Rashedul in Journal of hydraulic research, Vol. 49 N° 5 (Septembre/Octobre 2011) 

Public ISBD [article]  in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 595-600 Titre : A numerical study of confined wall jets in a shallow basin Type de document : texte imprimé Auteurs : Islam Mohammed Rashedul, Auteur ; David Z. Zhu, Auteur Année de publication : 2011 Article en page(s) : pp. 595-600 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : CFD  Confined  wall  jet  Pressure  Recirculation  Reynolds  number Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : A numerical study was conducted to investigate the effect of confinement on wall jets in a rectangular water basin using a slot inlet. The inlet slot creates a wall jet on the bottom of the basin with a recirculation zone on top of it. The classical wall jet behaviour is observed only up to the centre of the recirculation zone, beyond that point the momentum flux is not conserved and the wall jet behaviour is lost. Empirical expressions are developed to estimate the velocity decay and the jet spreading rates, and the maximum wall shear stress. The two outlet types and their location did not affect the wall jet and the recirculation zones, if the outlet is placed at a distance greater than the normal extent of the recirculation zone. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.588779 [article] A numerical study of confined wall jets in a shallow basin [texte imprimé] / Islam Mohammed Rashedul, Auteur ; David Z. Zhu, Auteur . - 2011 . - pp. 595-600. Hydraulique Langues : Anglais (eng) in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 595-600 Mots-clés : CFD  Confined  wall  jet  Pressure  Recirculation  Reynolds  number Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : A numerical study was conducted to investigate the effect of confinement on wall jets in a rectangular water basin using a slot inlet. The inlet slot creates a wall jet on the bottom of the basin with a recirculation zone on top of it. The classical wall jet behaviour is observed only up to the centre of the recirculation zone, beyond that point the momentum flux is not conserved and the wall jet behaviour is lost. Empirical expressions are developed to estimate the velocity decay and the jet spreading rates, and the maximum wall shear stress. The two outlet types and their location did not affect the wall jet and the recirculation zones, if the outlet is placed at a distance greater than the normal extent of the recirculation zone. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.588779

Experimental study on sand bed excavation by impinging swirling jets / Joaquin Ortega-Casanova in Journal of hydraulic research, Vol. 49 N° 5 (Septembre/Octobre 2011) 

Public ISBD [article]  in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 601-610 Titre : Experimental study on sand bed excavation by impinging swirling jets Type de document : texte imprimé Auteurs : Joaquin Ortega-Casanova, Auteur ; Nicolas Campos, Auteur ; Ramon Fernandez-Feria, Auteur Année de publication : 2011 Article en page(s) : pp. 601-610 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Erodible  bed  Scour  Sediment  transport  Swirling  jet  Velocity  profile Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : The excavation performance of swirling jets impinging normally against a sand bed from several distances is described. A specially-designed nozzle with adjustable swirl vanes was used to generate swirling jets of various swirl intensities. Two sand beds of different grain size distributions were considered. The main scour patterns on the sand bed produced by the swirling jets were measured by image processing of photographs of the bed illuminated by a laser sheet. The velocity profiles of the swirling jets at the nozzle exit were measured using Laser Doppler Anemometry for various test conditions. The scour patterns were then analysed in relation to the details of the velocity profile of the swirling jets, their Reynolds numbers and the distances from the nozzle to the bed. The optimum jet features resulting from the different swirl nozzles and the best impinging distances for sea bed excavation are identified and discussed. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.593346 [article] Experimental study on sand bed excavation by impinging swirling jets [texte imprimé] / Joaquin Ortega-Casanova, Auteur ; Nicolas Campos, Auteur ; Ramon Fernandez-Feria, Auteur . - 2011 . - pp. 601-610. Hydraulique Langues : Anglais (eng) in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 601-610 Mots-clés : Erodible  bed  Scour  Sediment  transport  Swirling  jet  Velocity  profile Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : The excavation performance of swirling jets impinging normally against a sand bed from several distances is described. A specially-designed nozzle with adjustable swirl vanes was used to generate swirling jets of various swirl intensities. Two sand beds of different grain size distributions were considered. The main scour patterns on the sand bed produced by the swirling jets were measured by image processing of photographs of the bed illuminated by a laser sheet. The velocity profiles of the swirling jets at the nozzle exit were measured using Laser Doppler Anemometry for various test conditions. The scour patterns were then analysed in relation to the details of the velocity profile of the swirling jets, their Reynolds numbers and the distances from the nozzle to the bed. The optimum jet features resulting from the different swirl nozzles and the best impinging distances for sea bed excavation are identified and discussed. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.593346

Observations of canonical flow resistance in fast-flowing sand bed rivers / Nicolas Huybrechts in Journal of hydraulic research, Vol. 49 N° 5 (Septembre/Octobre 2011) 

Public ISBD [article]  in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 611-616 Titre : Observations of canonical flow resistance in fast-flowing sand bed rivers Type de document : texte imprimé Auteurs : Nicolas Huybrechts, Auteur ; Giang Vu Luong, Auteur ; Yuanfeng Zhang, Auteur Année de publication : 2011 Article en page(s) : pp. 611-616 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Alluvial  regime  Drag  reduction  In-phase  waves  Mobile  bed  forms  Movable-bed  resistance  Optimum  bed  form  configuration  Separated  and  reattaching  flow  Vortex  drag  model Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : Field data are here re-interpreted using the Vortex–Drag equation for evaluating the alluvial resistance in a sand bed river. The Vortex–Drag equation introduces the Rossiter resonance concept into alluvial hydraulics. It appears that this equation is more consistent than the Manning approach for the lower alluvial regime since a ripple configuration effectively induces a lower flow resistance coefficient than a duned configuration. A systematic decrease in the control factor down to a canonical value during the transition from the lower to the upper alluvial regime is found for well-contrasted freshet events. It results that during high stream power events with maximum river bed reshaping, the flow pattern is reproduced by simply imposing this canonical value. This is most welcome in alluvial hydraulic routing, because peak-discharge events are generally these which are the most difficult to characterize in a straightforward way, both experimentally and numerically. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.596651 [article] Observations of canonical flow resistance in fast-flowing sand bed rivers [texte imprimé] / Nicolas Huybrechts, Auteur ; Giang Vu Luong, Auteur ; Yuanfeng Zhang, Auteur . - 2011 . - pp. 611-616. Hydraulique Langues : Anglais (eng) in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 611-616 Mots-clés : Alluvial  regime  Drag  reduction  In-phase  waves  Mobile  bed  forms  Movable-bed  resistance  Optimum  bed  form  configuration  Separated  and  reattaching  flow  Vortex  drag  model Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : Field data are here re-interpreted using the Vortex–Drag equation for evaluating the alluvial resistance in a sand bed river. The Vortex–Drag equation introduces the Rossiter resonance concept into alluvial hydraulics. It appears that this equation is more consistent than the Manning approach for the lower alluvial regime since a ripple configuration effectively induces a lower flow resistance coefficient than a duned configuration. A systematic decrease in the control factor down to a canonical value during the transition from the lower to the upper alluvial regime is found for well-contrasted freshet events. It results that during high stream power events with maximum river bed reshaping, the flow pattern is reproduced by simply imposing this canonical value. This is most welcome in alluvial hydraulic routing, because peak-discharge events are generally these which are the most difficult to characterize in a straightforward way, both experimentally and numerically. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.596651

Prediction of time-dependent channel meander migration based on large-scale laboratory experiments / Po-Hung Yeh in Journal of hydraulic research, Vol. 49 N° 5 (Septembre/Octobre 2011) 

Public ISBD [article]  in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 617-629 Titre : Prediction of time-dependent channel meander migration based on large-scale laboratory experiments Type de document : texte imprimé Auteurs : Po-Hung Yeh, Auteur ; Namgyu Park, Auteur ; Chang, Kuang-An, Auteur Année de publication : 2011 Article en page(s) : pp. 617-629 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Meander  migration  Migration  rate  Secondary  flow  Soil  property  Thalweg Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : Channel centreline migration rates were derived from a set of large-scale laboratory experiments. The channel radius of curvature, bend angle, and discharge were varied to evaluate correlations between the channel centreline migration rate and the controlling geometry and hydraulic conditions. An excessive Froude number was adopted to account for soil resistance strength. The intersection of the channel centreline between two consecutive time steps was identified. A phase lag of angle to channel curvature exists in both channel plan form and the onset of cross-section scour. The migration rate between two successive inflection points of migration exhibits a growth and decay pattern and is modelled using a sine function related to the channel geometry, the flow condition, and the soil property. A three-equation prediction method was developed and applied to a natural river in Texas. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.596704 [article] Prediction of time-dependent channel meander migration based on large-scale laboratory experiments [texte imprimé] / Po-Hung Yeh, Auteur ; Namgyu Park, Auteur ; Chang, Kuang-An, Auteur . - 2011 . - pp. 617-629. Hydraulique Langues : Anglais (eng) in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 617-629 Mots-clés : Meander  migration  Migration  rate  Secondary  flow  Soil  property  Thalweg Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : Channel centreline migration rates were derived from a set of large-scale laboratory experiments. The channel radius of curvature, bend angle, and discharge were varied to evaluate correlations between the channel centreline migration rate and the controlling geometry and hydraulic conditions. An excessive Froude number was adopted to account for soil resistance strength. The intersection of the channel centreline between two consecutive time steps was identified. A phase lag of angle to channel curvature exists in both channel plan form and the onset of cross-section scour. The migration rate between two successive inflection points of migration exhibits a growth and decay pattern and is modelled using a sine function related to the channel geometry, the flow condition, and the soil property. A three-equation prediction method was developed and applied to a natural river in Texas. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.596704

RADINS equations for aerated shallow water flows over rough beds / Dubravka Pokrajac in Journal of hydraulic research, Vol. 49 N° 5 (Septembre/Octobre 2011) 

Public ISBD [article]  in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 630-638 Titre : RADINS equations for aerated shallow water flows over rough beds Type de document : texte imprimé Auteurs : Dubravka Pokrajac, Auteur ; Gustaaf Adriaan Kikkert, Auteur Année de publication : 2011 Article en page(s) : pp. 630-638 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Depth-averaged  flow  DIRANS  equations  NLSWE  RADINS  equations  Turbulence Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : Depth-averaged equations describing turbulent free-surface flows are usually derived assuming that the free surface is constant over a statistical ensemble of realizations. This work presents the derivation of the Reynolds-Averaged-Depth-Integrated Navier–Stokes (RADINS) equations obtained if this assumption is removed. These equations are applied to transient turbulent open-channel flow over a rough bed with an aerated free surface containing air bubbles. The RADINS equations contain terms which explicitly include the contribution of turbulent free-surface fluctuations to the large-scale volume and momentum transfer. These terms are evaluated in a laboratory experiment which involves a turbulent bore climbing up a rough slope. The new RADINS equations are compared with the conventional depth-integrated-Reynolds-averaged Navier–Stokes (DIRANS) equations. The RADINS and DIRANS equations are identical only for flows with negligible depth fluctuations. If this condition is not satisfied, the equations are different and the terms in the RADINS equations have a clearer physical meaning. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.597940 [article] RADINS equations for aerated shallow water flows over rough beds [texte imprimé] / Dubravka Pokrajac, Auteur ; Gustaaf Adriaan Kikkert, Auteur . - 2011 . - pp. 630-638. Hydraulique Langues : Anglais (eng) in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 630-638 Mots-clés : Depth-averaged  flow  DIRANS  equations  NLSWE  RADINS  equations  Turbulence Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : Depth-averaged equations describing turbulent free-surface flows are usually derived assuming that the free surface is constant over a statistical ensemble of realizations. This work presents the derivation of the Reynolds-Averaged-Depth-Integrated Navier–Stokes (RADINS) equations obtained if this assumption is removed. These equations are applied to transient turbulent open-channel flow over a rough bed with an aerated free surface containing air bubbles. The RADINS equations contain terms which explicitly include the contribution of turbulent free-surface fluctuations to the large-scale volume and momentum transfer. These terms are evaluated in a laboratory experiment which involves a turbulent bore climbing up a rough slope. The new RADINS equations are compared with the conventional depth-integrated-Reynolds-averaged Navier–Stokes (DIRANS) equations. The RADINS and DIRANS equations are identical only for flows with negligible depth fluctuations. If this condition is not satisfied, the equations are different and the terms in the RADINS equations have a clearer physical meaning. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.597940

Developing flow in skimming flow regime on embankment stepped spillways / Daniel B. Bung in Journal of hydraulic research, Vol. 49 N° 5 (Septembre/Octobre 2011) 

Public ISBD [article]  in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 639-648 Titre : Developing flow in skimming flow regime on embankment stepped spillways Type de document : texte imprimé Auteurs : Daniel B. Bung, Auteur Année de publication : 2011 Article en page(s) : pp. 639-648 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Air–water  flow  Developing  flow  Physical  modelling  Self-aeration  Stepped  spillway Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : In hydraulic engineering, stepped spillways are effective structures in regard to both energy dissipation and re-aeration processes. It is well known that flow depths and flow velocities generally depend on the spillway geometry in terms of slope and step-induced macro-roughness height on the one hand and the discharge on the other hand. Moreover, these parameters affect the air entrainment process and hence, the amount and the size of entrained air bubbles which are directly linked to the specific air–water interface being of particular significance for oxygen transfer. In this study, physical model investigations on a stepped spillway scaled 1:10 of varying step height, chute angle and discharge are conducted with the objective to analyse the development of these air–water flow properties in the non-uniform flow region. Measurements of air–water mixture velocity and air concentration are carried out by the use of an intrusive double-tip conductivity probe. It is found that the step-induced macro-roughness has a differing effect on particular flow characteristics. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.584372 [article] Developing flow in skimming flow regime on embankment stepped spillways [texte imprimé] / Daniel B. Bung, Auteur . - 2011 . - pp. 639-648. Hydraulique Langues : Anglais (eng) in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 639-648 Mots-clés : Air–water  flow  Developing  flow  Physical  modelling  Self-aeration  Stepped  spillway Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : In hydraulic engineering, stepped spillways are effective structures in regard to both energy dissipation and re-aeration processes. It is well known that flow depths and flow velocities generally depend on the spillway geometry in terms of slope and step-induced macro-roughness height on the one hand and the discharge on the other hand. Moreover, these parameters affect the air entrainment process and hence, the amount and the size of entrained air bubbles which are directly linked to the specific air–water interface being of particular significance for oxygen transfer. In this study, physical model investigations on a stepped spillway scaled 1:10 of varying step height, chute angle and discharge are conducted with the objective to analyse the development of these air–water flow properties in the non-uniform flow region. Measurements of air–water mixture velocity and air concentration are carried out by the use of an intrusive double-tip conductivity probe. It is found that the step-induced macro-roughness has a differing effect on particular flow characteristics. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.584372

Flow over sills by the MPS mesh-free particle method / Aidin Jabbari Sahebari in Journal of hydraulic research, Vol. 49 N° 5 (Septembre/Octobre 2011) 

Public ISBD [article]  in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 649-656 Titre : Flow over sills by the MPS mesh-free particle method Type de document : texte imprimé Auteurs : Aidin Jabbari Sahebari, Auteur ; Jin, Yee-Chung, Auteur ; Ahmad Shakibaeinia, Auteur Année de publication : 2011 Article en page(s) : pp. 649-656 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Free  surface  Interface  MPS  Numerical  model  Particle  method  Sill  Velocity  profile Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : A particular flow structure and the behaviour of free surface complicate flow modelling over sills, especially if the free surface is highly deformed and made up of spray. Mesh-free particle methods have recently been developed to increase the flexibility and accuracy of numerical methods to deal with these boundaries and interfaces. This research aims to develop, apply, and evaluate the capabilities of one of the particle methods, the moving particle semi-implicit method, for modelling flow over sills under various flow regimes. The model developed, along with modifications in its pressure calculation and boundary definition techniques, is applied to predict the free surface and the velocity profiles of sill flow. These results are compared with experimental measurements and results from other numerical techniques. They are demonstrated to agree well with the experiments, indicating that the model simulates velocity profiles and free surface fluctuations reasonably. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.607302 [article] Flow over sills by the MPS mesh-free particle method [texte imprimé] / Aidin Jabbari Sahebari, Auteur ; Jin, Yee-Chung, Auteur ; Ahmad Shakibaeinia, Auteur . - 2011 . - pp. 649-656. Hydraulique Langues : Anglais (eng) in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 649-656 Mots-clés : Free  surface  Interface  MPS  Numerical  model  Particle  method  Sill  Velocity  profile Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : A particular flow structure and the behaviour of free surface complicate flow modelling over sills, especially if the free surface is highly deformed and made up of spray. Mesh-free particle methods have recently been developed to increase the flexibility and accuracy of numerical methods to deal with these boundaries and interfaces. This research aims to develop, apply, and evaluate the capabilities of one of the particle methods, the moving particle semi-implicit method, for modelling flow over sills under various flow regimes. The model developed, along with modifications in its pressure calculation and boundary definition techniques, is applied to predict the free surface and the velocity profiles of sill flow. These results are compared with experimental measurements and results from other numerical techniques. They are demonstrated to agree well with the experiments, indicating that the model simulates velocity profiles and free surface fluctuations reasonably. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.607302

CFD modelling of selected laboratory turbidity currents / Ke Yam in Journal of hydraulic research, Vol. 49 N° 5 (Septembre/Octobre 2011) 

Public ISBD [article]  in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 657-666 Titre : CFD modelling of selected laboratory turbidity currents Type de document : texte imprimé Auteurs : Ke Yam, Auteur ; William D. McCaffrey, Auteur ; Derek B. Ingham, Auteur Année de publication : 2011 Article en page(s) : pp. 657-666 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : CFD  Lock  release  Mixture  model  Turbidity  currents  Turbulence  dispersion Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : A Computational Fluid Dynamics (CFD) investigation was conducted to evaluate the accuracy and validity of the algebraic slip model in predicting the evolution of turbidity currents. The scenario used to run the model simulation was an experimental lock release of mono-disperse and bi-disperse turbidity currents. The general flow structure of the simulated currents compares well with the general experimental observation. The model used predicts the deposition from currents carrying coarse particles relatively well but excessively over-predicts the deposition rate in currents carrying fine particles. Incorporation of the Simonin model turbulence dispersion into the original model reduces the sediment deposition rate but incurs an excessive dispersion force. Thus, still another turbulence modulation model was incorporated into the finally proposed version and the mono-disperse flow was then re-simulated, and yet only small changes were observed in the results. It is concluded that improved results will be achieved by using more accurate turbulence dispersion models. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.607303 [article] CFD modelling of selected laboratory turbidity currents [texte imprimé] / Ke Yam, Auteur ; William D. McCaffrey, Auteur ; Derek B. Ingham, Auteur . - 2011 . - pp. 657-666. Hydraulique Langues : Anglais (eng) in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 657-666 Mots-clés : CFD  Lock  release  Mixture  model  Turbidity  currents  Turbulence  dispersion Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : A Computational Fluid Dynamics (CFD) investigation was conducted to evaluate the accuracy and validity of the algebraic slip model in predicting the evolution of turbidity currents. The scenario used to run the model simulation was an experimental lock release of mono-disperse and bi-disperse turbidity currents. The general flow structure of the simulated currents compares well with the general experimental observation. The model used predicts the deposition from currents carrying coarse particles relatively well but excessively over-predicts the deposition rate in currents carrying fine particles. Incorporation of the Simonin model turbulence dispersion into the original model reduces the sediment deposition rate but incurs an excessive dispersion force. Thus, still another turbulence modulation model was incorporated into the finally proposed version and the mono-disperse flow was then re-simulated, and yet only small changes were observed in the results. It is concluded that improved results will be achieved by using more accurate turbulence dispersion models. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.607303

Spatially-varied open channel flow equations with vertical inertia / Oscar Castro-Orgaz in Journal of hydraulic research, Vol. 49 N° 5 (Septembre/Octobre 2011) 

Public ISBD [article]  in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 667-675 Titre : Spatially-varied open channel flow equations with vertical inertia Type de document : texte imprimé Auteurs : Oscar Castro-Orgaz, Auteur ; Willi H. Hager, Auteur Année de publication : 2011 Article en page(s) : pp. 667-675 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Bottom  outlet  0pen  channel  Side-weir  Spatially-varied  flow  Two-dimensional  flow Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : Spatially-varied open channel flows with a streamwise discharge variation occur in the side-weir, side-channel and bottom outlet. The governing equations were formulated in the 1970s by Yen and Wenzel. However, no attempts were made to provide closure to the energy and momentum systems in terms of velocity and pressure conditions. Therefore, the current theoretical knowledge relates to the hydraulic approach based on uniform velocity and hydrostatic pressure distributions, which is known for deviations from real conditions in spatially-varied flow problems. Herein, Boussinesq's theory is applied including vertical inertia to spatially-varied flows, resulting in a higher-order closed-form system of equations for energy and momentum generalizing the theoretical development of Yen and Wenzel. The novel Boussinesq system contains terms accounting for spatially-varied discharge. This development is applied to the practical case of bottom outlet flow, resulting in good agreement with experimental results. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.588774 [article] Spatially-varied open channel flow equations with vertical inertia [texte imprimé] / Oscar Castro-Orgaz, Auteur ; Willi H. Hager, Auteur . - 2011 . - pp. 667-675. Hydraulique Langues : Anglais (eng) in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 667-675 Mots-clés : Bottom  outlet  0pen  channel  Side-weir  Spatially-varied  flow  Two-dimensional  flow Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : Spatially-varied open channel flows with a streamwise discharge variation occur in the side-weir, side-channel and bottom outlet. The governing equations were formulated in the 1970s by Yen and Wenzel. However, no attempts were made to provide closure to the energy and momentum systems in terms of velocity and pressure conditions. Therefore, the current theoretical knowledge relates to the hydraulic approach based on uniform velocity and hydrostatic pressure distributions, which is known for deviations from real conditions in spatially-varied flow problems. Herein, Boussinesq's theory is applied including vertical inertia to spatially-varied flows, resulting in a higher-order closed-form system of equations for energy and momentum generalizing the theoretical development of Yen and Wenzel. The novel Boussinesq system contains terms accounting for spatially-varied discharge. This development is applied to the practical case of bottom outlet flow, resulting in good agreement with experimental results. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.588774

Turbulent flow characteristics in circular corrugated culverts at mild slopes / Shawn P. Clark in Journal of hydraulic research, Vol. 49 N° 5 (Septembre/Octobre 2011) 

Public ISBD [article]  in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 676-684 Titre : Turbulent flow characteristics in circular corrugated culverts at mild slopes Type de document : texte imprimé Auteurs : Shawn P. Clark, Auteur ; Nicholas Kehler, Auteur Année de publication : 2011 Article en page(s) : pp. 676-684 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Culvert  Fish  passage  Secondary  current  Shear  stress  Turbulence  Velocity  distribution Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : Anthropogenic barriers to fish passage at stream crossings are an important issue in North America. Environmental regulations impose velocity restrictions on culvert flow, which may be overly simplistic. A series of laboratory experiments were conducted in a corrugated metal pipe culvert at three mild slopes. Acoustic Doppler velocimeters were used to measure velocity and turbulence quantities. A significant percentage of the cross-sectional flow area was found to have a streamwise velocity lower than the mean bulk velocity. Secondary currents were measured and are believed to contribute to the strong velocity dip at the water surface and the non-uniform shape of the boundary shear stress distribution. A modified version of the log law is proposed to estimate water velocities within the fully-developed flow region. Results may be of interest to hydraulic engineers and regulators involved with fish passage issues at stream crossings as also for calibration and verification of numerical culvert models. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.596399 [article] Turbulent flow characteristics in circular corrugated culverts at mild slopes [texte imprimé] / Shawn P. Clark, Auteur ; Nicholas Kehler, Auteur . - 2011 . - pp. 676-684. Hydraulique Langues : Anglais (eng) in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 676-684 Mots-clés : Culvert  Fish  passage  Secondary  current  Shear  stress  Turbulence  Velocity  distribution Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : Anthropogenic barriers to fish passage at stream crossings are an important issue in North America. Environmental regulations impose velocity restrictions on culvert flow, which may be overly simplistic. A series of laboratory experiments were conducted in a corrugated metal pipe culvert at three mild slopes. Acoustic Doppler velocimeters were used to measure velocity and turbulence quantities. A significant percentage of the cross-sectional flow area was found to have a streamwise velocity lower than the mean bulk velocity. Secondary currents were measured and are believed to contribute to the strong velocity dip at the water surface and the non-uniform shape of the boundary shear stress distribution. A modified version of the log law is proposed to estimate water velocities within the fully-developed flow region. Results may be of interest to hydraulic engineers and regulators involved with fish passage issues at stream crossings as also for calibration and verification of numerical culvert models. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.596399

Numerical modelling of supercritical flow in rectangular chute bends / Mahnaz Ghaeini-Hessaroeyeh in Journal of hydraulic research, Vol. 49 N° 5 (Septembre/Octobre 2011) 

Public ISBD [article]  in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 685-688 Titre : Numerical modelling of supercritical flow in rectangular chute bends Type de document : texte imprimé Auteurs : Mahnaz Ghaeini-Hessaroeyeh, Auteur ; Ahmad Tahershamsi, Auteur ; Masoud Montazeri Namin, Auteur Année de publication : 2011 Article en page(s) : pp. 685-688 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Bend  Finite  volume  method  Shallow-water  equations  Supercritical  flow  TVD–WAF  method Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : A two-dimensional numerical model predicting supercritical flow in open channels has been developed using the finite volume method. The shallow-water equations are solved by the total variation diminishing weighted average flux method. Then the model is applied to a wide range of supercritical flow tests in rectangular chute bends and the results are compared with available experimental data. The results indicate that the model predicts the flow profile well for the channel bend with a width to channel curvature ratio of 0.04 and the present model has limitations for the other tests which have a higher ratio. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.589130 [article] Numerical modelling of supercritical flow in rectangular chute bends [texte imprimé] / Mahnaz Ghaeini-Hessaroeyeh, Auteur ; Ahmad Tahershamsi, Auteur ; Masoud Montazeri Namin, Auteur . - 2011 . - pp. 685-688. Hydraulique Langues : Anglais (eng) in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 685-688 Mots-clés : Bend  Finite  volume  method  Shallow-water  equations  Supercritical  flow  TVD–WAF  method Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : A two-dimensional numerical model predicting supercritical flow in open channels has been developed using the finite volume method. The shallow-water equations are solved by the total variation diminishing weighted average flux method. Then the model is applied to a wide range of supercritical flow tests in rectangular chute bends and the results are compared with available experimental data. The results indicate that the model predicts the flow profile well for the channel bend with a width to channel curvature ratio of 0.04 and the present model has limitations for the other tests which have a higher ratio. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.589130

Observations on undular hydraulic jump in movable bed / Oscar Castro-Orgaz in Journal of hydraulic research, Vol. 49 N° 5 (Septembre/Octobre 2011) 

Public ISBD [article]  in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 689-692 Titre : Observations on undular hydraulic jump in movable bed Type de document : texte imprimé Auteurs : Oscar Castro-Orgaz, Auteur ; Willi H. Hager, Auteur Année de publication : 2011 Article en page(s) : pp. 689-692 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Boundary  layer  Hydraulic  jump  Shear  stress  Transitional  flow  Turbulence  Undular  flow Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : Near-critical flows in rivers and natural streams usually present a wavelike undular free surface, associated with dune-type bed-forms. The formation of this particular bed geometry is related to the shear stress acting on the river bed. The boundary shear stress distribution of undular flows was considered by Engelund and Hansen, stating that standing waves and their associated non-uniform shear stresses are responsible for bed-form generation in rivers. However, observations on movable-bed channels involving transcritical flow were not considered. In this note, an exploratory analysis is conducted to outline the analogy between the boundary shear in fixed-bed undular flows and the bed-form shape. Experimental observations reveal a strong analogy, supporting the original hypothesis of Engelund and Hansen. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.593879 [article] Observations on undular hydraulic jump in movable bed [texte imprimé] / Oscar Castro-Orgaz, Auteur ; Willi H. Hager, Auteur . - 2011 . - pp. 689-692. Hydraulique Langues : Anglais (eng) in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 689-692 Mots-clés : Boundary  layer  Hydraulic  jump  Shear  stress  Transitional  flow  Turbulence  Undular  flow Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : Near-critical flows in rivers and natural streams usually present a wavelike undular free surface, associated with dune-type bed-forms. The formation of this particular bed geometry is related to the shear stress acting on the river bed. The boundary shear stress distribution of undular flows was considered by Engelund and Hansen, stating that standing waves and their associated non-uniform shear stresses are responsible for bed-form generation in rivers. However, observations on movable-bed channels involving transcritical flow were not considered. In this note, an exploratory analysis is conducted to outline the analogy between the boundary shear in fixed-bed undular flows and the bed-form shape. Experimental observations reveal a strong analogy, supporting the original hypothesis of Engelund and Hansen. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.593879

Analytical Froude number solution for reservoir density inflows / Yuanya Li in Journal of hydraulic research, Vol. 49 N° 5 (Septembre/Octobre 2011) 

Public ISBD [article]  in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 693-696 Titre : Analytical Froude number solution for reservoir density inflows Type de document : texte imprimé Auteurs : Yuanya Li, Auteur ; Junhua Zhang, Auteur ; Huaibao Ma, Auteur Année de publication : 2011 Article en page(s) : pp. 693-696 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Energy  balance  Froude  number  Gravity  current  Reservoir  sedimentation  Turbidity  current Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : This research presents a theoretical Froude number model at the incipient plunging point for a gravity current advancing into a sloping ambient reservoir. The analysis is based on the balance of potential energy, kinetic energy and energy losses. The Froude number at the incipient plunging point attracted attention in recent years. There are two opinions: either the Froude number is considered a constant, whereas others find it as variable in a wide range, depending on the bottom slope and the sediment concentration. The theoretical solution presented herein resolves the problem by stating that the Froude number is the function of bottom slope, relative thickness of the density current and the friction coefficient. Moreover, this theoretical analysis unifies all previous researches culminating in a general solution of the problem. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.593905 [article] Analytical Froude number solution for reservoir density inflows [texte imprimé] / Yuanya Li, Auteur ; Junhua Zhang, Auteur ; Huaibao Ma, Auteur . - 2011 . - pp. 693-696. Hydraulique Langues : Anglais (eng) in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 693-696 Mots-clés : Energy  balance  Froude  number  Gravity  current  Reservoir  sedimentation  Turbidity  current Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : This research presents a theoretical Froude number model at the incipient plunging point for a gravity current advancing into a sloping ambient reservoir. The analysis is based on the balance of potential energy, kinetic energy and energy losses. The Froude number at the incipient plunging point attracted attention in recent years. There are two opinions: either the Froude number is considered a constant, whereas others find it as variable in a wide range, depending on the bottom slope and the sediment concentration. The theoretical solution presented herein resolves the problem by stating that the Froude number is the function of bottom slope, relative thickness of the density current and the friction coefficient. Moreover, this theoretical analysis unifies all previous researches culminating in a general solution of the problem. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.593905

Numerical study of saltation of non-uniform grains / Robert J. Bialik in Journal of hydraulic research, Vol. 49 N° 5 (Septembre/Octobre 2011) 

Public ISBD [article]  in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 697-701 Titre : Numerical study of saltation of non-uniform grains Type de document : texte imprimé Auteurs : Robert J. Bialik, Auteur Année de publication : 2011 Article en page(s) : pp. 697-701 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Collision  angle  Lagrangian  approach  Particle-bed  collision  Particle  diffusion  Saltation Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : A theoretical model of non-uniform saltating grains in a turbulent open-channel flow based on the Lagrangian approach is developed. In the analysis described herein, a more realistic stochastic model of particle-bed collision is proposed. Based on geometrical considerations, new formulas for the minimum and maximum values of the angle of the collision surface with an irregular bed are derived. A Monte Carlo simulation of the distribution of saltating and colliding particles is introduced. Numerical simulations of possible particles trajectories with different sizes in an open-channel flow are presented. It is demonstrated that the particle-bed collision mechanism exactly depends on different particles sizes and the bed structure. Application for the analysis of the longitudinal saltating particle diffusion is presented, and the problem with the initial conditions in numerical simulations of particle motion is briefly described. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.598025 [article] Numerical study of saltation of non-uniform grains [texte imprimé] / Robert J. Bialik, Auteur . - 2011 . - pp. 697-701. Hydraulique Langues : Anglais (eng) in Journal of hydraulic research > Vol. 49 N° 5 (Septembre/Octobre 2011) . - pp. 697-701 Mots-clés : Collision  angle  Lagrangian  approach  Particle-bed  collision  Particle  diffusion  Saltation Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : A theoretical model of non-uniform saltating grains in a turbulent open-channel flow based on the Lagrangian approach is developed. In the analysis described herein, a more realistic stochastic model of particle-bed collision is proposed. Based on geometrical considerations, new formulas for the minimum and maximum values of the angle of the collision surface with an irregular bed are derived. A Monte Carlo simulation of the distribution of saltating and colliding particles is introduced. Numerical simulations of possible particles trajectories with different sizes in an open-channel flow are presented. It is demonstrated that the particle-bed collision mechanism exactly depends on different particles sizes and the bed structure. Application for the analysis of the longitudinal saltating particle diffusion is presented, and the problem with the initial conditions in numerical simulations of particle motion is briefly described. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.598025

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