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Journal of hydraulic research |
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Ajouter le résultat dans votre panierInclined negatively buoyant jets 1 / Ilias G. Papakonstantis in Journal of hydraulic research, Vol. 49 N° 1 (Janvier/Fevrier 2011)
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 3-12
Titre : Inclined negatively buoyant jets 1 : geometrical characteristics Type de document : texte imprimé Auteurs : Ilias G. Papakonstantis, Auteur ; George C. Christodoulou, Auteur ; Panos N. Papanicolaou, Auteur Année de publication : 2011 Article en page(s) : pp. 3-12 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Buoyant jet Desalination brine Discharge angle Jet trajectory Negative buoyancy Turbulent jet 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 : Experimental results on inclined turbulent round jets with negative buoyancy discharging in a calm homogeneous fluid are presented. Six different discharge angles from 45° to 90° to the horizontal are studied, and the jet evolution is recorded by means of a video camera. Results concern the main geometrical characteristics of the jet trajectory, i.e. the initial terminal height of rise reached by the jet at flow initiation, the final terminal height of rise observed at steady state, the horizontal distance from the source at which the terminal height is observed and the horizontal distance to the point where the jet returns at the source elevation. The densimetric Froude number at the source ranges between 7 and 60, whereas the Reynolds number is generally higher than 6000. Results are given in dimensionless form and confirm theoretical considerations obtained by dimensional analysis.
DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933308831~frm=titlelink [article] Inclined negatively buoyant jets 1 : geometrical characteristics [texte imprimé] / Ilias G. Papakonstantis, Auteur ; George C. Christodoulou, Auteur ; Panos N. Papanicolaou, Auteur . - 2011 . - pp. 3-12.
Hydraulique
Langues : Anglais (eng)
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 3-12
Mots-clés : Buoyant jet Desalination brine Discharge angle Jet trajectory Negative buoyancy Turbulent jet 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 : Experimental results on inclined turbulent round jets with negative buoyancy discharging in a calm homogeneous fluid are presented. Six different discharge angles from 45° to 90° to the horizontal are studied, and the jet evolution is recorded by means of a video camera. Results concern the main geometrical characteristics of the jet trajectory, i.e. the initial terminal height of rise reached by the jet at flow initiation, the final terminal height of rise observed at steady state, the horizontal distance from the source at which the terminal height is observed and the horizontal distance to the point where the jet returns at the source elevation. The densimetric Froude number at the source ranges between 7 and 60, whereas the Reynolds number is generally higher than 6000. Results are given in dimensionless form and confirm theoretical considerations obtained by dimensional analysis.
DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933308831~frm=titlelink
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 13-22
Titre : Inclined negatively buoyant jets 2 : concentration measurements Type de document : texte imprimé Auteurs : Ilias G. Papakonstantis, Auteur ; George C. Christodoulou, Auteur ; Panos N. Papanicolaou, Auteur Année de publication : 2011 Article en page(s) : pp. 13-22 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Concentration Desalination brine Dilution Inclined turbulent jet Negative buoyancy Turbulent intensity 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 : Experiments on concentration measurements in round turbulent negatively buoyant jets discharging into a calm homogeneous fluid at three different angles are presented. Detailed measurements using a micro-scale conductivity probe were carried out at the horizontal location of the terminal rise height, mostly along the vertical of the axial jet plane and in the transverse direction. The dimensionless vertical distribution of the mean concentration is found to be asymmetric, whereas the transverse distribution is approximately Gaussian. At the same horizontal location, the vertical distribution of the concentration turbulent intensity has a maximum at a point systematically higher than the jet axis. The width of the mean concentration distribution, the heights to the location of the maximum mean concentration and to the maximum turbulent intensity as well as the minimum dilution are determined. From measurements in the region where the jet returns to the source elevation, the minimum dilution and the horizontal distance to the return point are estimated.
DEWEY : 627 ISSN : 0022.1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933312970~frm=titlelink [article] Inclined negatively buoyant jets 2 : concentration measurements [texte imprimé] / Ilias G. Papakonstantis, Auteur ; George C. Christodoulou, Auteur ; Panos N. Papanicolaou, Auteur . - 2011 . - pp. 13-22.
Hydraulique
Langues : Anglais (eng)
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 13-22
Mots-clés : Concentration Desalination brine Dilution Inclined turbulent jet Negative buoyancy Turbulent intensity 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 : Experiments on concentration measurements in round turbulent negatively buoyant jets discharging into a calm homogeneous fluid at three different angles are presented. Detailed measurements using a micro-scale conductivity probe were carried out at the horizontal location of the terminal rise height, mostly along the vertical of the axial jet plane and in the transverse direction. The dimensionless vertical distribution of the mean concentration is found to be asymmetric, whereas the transverse distribution is approximately Gaussian. At the same horizontal location, the vertical distribution of the concentration turbulent intensity has a maximum at a point systematically higher than the jet axis. The width of the mean concentration distribution, the heights to the location of the maximum mean concentration and to the maximum turbulent intensity as well as the minimum dilution are determined. From measurements in the region where the jet returns to the source elevation, the minimum dilution and the horizontal distance to the return point are estimated.
DEWEY : 627 ISSN : 0022.1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933312970~frm=titlelink
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 23 - 31
Titre : Particle-particle collision in Lagrangian modelling of saltating grains Type de document : texte imprimé Auteurs : Robert J. Bialik, Auteur Année de publication : 2011 Article en page(s) : pp. 23 - 31 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Lagrangian model Particle-particle collision Saltating particle Sediment transport Turbulent velocity field 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 effect of particle-particle collision on the trajectories of saltating grains in open-channel flows is investigated. The vertical distributions of saltating particles are also analysed. A stochastic particle-particle collision model was designed to determine the collision probability along a particle trajectory, based on the assumption that inter-particle collision frequency may be described by the formula of kinetic gas theory. This parameter is the key quantity for the calculation of collision probability. The Monte Carlo simulation method is used to obtain the velocity and concentration of saltating particles. It is the first attempt to apply a probabilistic inter-particle collision approach to Lagrangian modelling of saltating grains. Trajectories of different particles with and without particle-particle collision are compared with available data. The proposed procedure allows verification of the hypothesis regarding the effect of the particle-particle collision on sediment transport. The described mechanism affects the vertical particle concentration and therefore may play an essential role in bed-load sediment transport.
DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933313380~frm=titlelink [article] Particle-particle collision in Lagrangian modelling of saltating grains [texte imprimé] / Robert J. Bialik, Auteur . - 2011 . - pp. 23 - 31.
Hydraulique
Langues : Anglais (eng)
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 23 - 31
Mots-clés : Lagrangian model Particle-particle collision Saltating particle Sediment transport Turbulent velocity field 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 effect of particle-particle collision on the trajectories of saltating grains in open-channel flows is investigated. The vertical distributions of saltating particles are also analysed. A stochastic particle-particle collision model was designed to determine the collision probability along a particle trajectory, based on the assumption that inter-particle collision frequency may be described by the formula of kinetic gas theory. This parameter is the key quantity for the calculation of collision probability. The Monte Carlo simulation method is used to obtain the velocity and concentration of saltating particles. It is the first attempt to apply a probabilistic inter-particle collision approach to Lagrangian modelling of saltating grains. Trajectories of different particles with and without particle-particle collision are compared with available data. The proposed procedure allows verification of the hypothesis regarding the effect of the particle-particle collision on sediment transport. The described mechanism affects the vertical particle concentration and therefore may play an essential role in bed-load sediment transport.
DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933313380~frm=titlelink
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 32-41
Titre : Motion of spheres falling through fluids Type de document : texte imprimé Auteurs : Junke Guo, Auteur Année de publication : 2011 Article en page(s) : pp. 32-41 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Added mass force Fluid-solid interaction Particle acceleration Powder technology Sphere drag 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 : Motion of spheres falling through fluids is a classic problem in fluid mechanics. The problem is solved for steady motion and other special cases such as for small and large Reynolds numbers, but not yet for transitional flow motion because of the complicated drag law. Recently, a series approximation for the transitional motion at zero initial velocity was proposed by applying a nonlinear perturbation method and Rubey's universal drag law to the Boussinesq-Basset-Oseen equation. This research presents a simple closed-form solution to the problem for arbitrary Reynolds numbers at nonzero initial velocity. The proposed solution is confirmed with experimental literature data and reproduces all well-known asymptotic values. The results can be directly used for particle size analysis in hydraulics laboratories; they may also help understanding the fluid-particle interactions in environmental engineering, meteorology, and powder technology.
DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933339750~frm=titlelink [article] Motion of spheres falling through fluids [texte imprimé] / Junke Guo, Auteur . - 2011 . - pp. 32-41.
Hydraulique
Langues : Anglais (eng)
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 32-41
Mots-clés : Added mass force Fluid-solid interaction Particle acceleration Powder technology Sphere drag 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 : Motion of spheres falling through fluids is a classic problem in fluid mechanics. The problem is solved for steady motion and other special cases such as for small and large Reynolds numbers, but not yet for transitional flow motion because of the complicated drag law. Recently, a series approximation for the transitional motion at zero initial velocity was proposed by applying a nonlinear perturbation method and Rubey's universal drag law to the Boussinesq-Basset-Oseen equation. This research presents a simple closed-form solution to the problem for arbitrary Reynolds numbers at nonzero initial velocity. The proposed solution is confirmed with experimental literature data and reproduces all well-known asymptotic values. The results can be directly used for particle size analysis in hydraulics laboratories; they may also help understanding the fluid-particle interactions in environmental engineering, meteorology, and powder technology.
DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933339750~frm=titlelink
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 42-54
Titre : Co-evolving delta faces under the condition of a moving sediment source Type de document : texte imprimé Auteurs : Rocio Luz Fernandez, Auteur ; Genevieve Cauchon-Voyer, Auteur ; Jacques Locat, Auteur Année de publication : 2011 Article en page(s) : pp. 42-54 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Fan delta Foreset slope Tailings Physical model Progradation 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 : A fan delta developed under the constraints of a moving point of flow-sediment supply is described. The sediment mixtures used in the experiments were chosen to approximate field conditions, with the coarser fractions depositing to form the topset (subaerial delta surface) and foreset, and the finer fractions forming a turbidity current that plunges near the shoreline, overrides the foreset, and continues into deeper water to emplace a bottomset. The migration rate of the feed point was adjusted so that the base of the lateral foreset along one side just touched the flume wall, so leaving open water on that side. The experiments provide insight into the sedimentation processes associated with these three co-evolving structures of the delta, i.e. its topset, foreset, and bottomset. The results indicate that the lateral delta extent can be controlled via the downstream migration of its sediment source.
DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933342443~frm=titlelink [article] Co-evolving delta faces under the condition of a moving sediment source [texte imprimé] / Rocio Luz Fernandez, Auteur ; Genevieve Cauchon-Voyer, Auteur ; Jacques Locat, Auteur . - 2011 . - pp. 42-54.
Hydraulique
Langues : Anglais (eng)
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 42-54
Mots-clés : Fan delta Foreset slope Tailings Physical model Progradation 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 : A fan delta developed under the constraints of a moving point of flow-sediment supply is described. The sediment mixtures used in the experiments were chosen to approximate field conditions, with the coarser fractions depositing to form the topset (subaerial delta surface) and foreset, and the finer fractions forming a turbidity current that plunges near the shoreline, overrides the foreset, and continues into deeper water to emplace a bottomset. The migration rate of the feed point was adjusted so that the base of the lateral foreset along one side just touched the flume wall, so leaving open water on that side. The experiments provide insight into the sedimentation processes associated with these three co-evolving structures of the delta, i.e. its topset, foreset, and bottomset. The results indicate that the lateral delta extent can be controlled via the downstream migration of its sediment source.
DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933342443~frm=titlelink
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 55-63
Titre : Steady free-surface flow in porous media: generalized Dupuit-Fawer equations Type de document : texte imprimé Auteurs : Oscar Castro-Orgaz, Auteur Année de publication : 2011 Article en page(s) : pp. 55-63 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Curvilinear flow Dam Flow net Open channel Seepage 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 : Steady free-surface flow in open channels may be analysed by the reduction of the two-dimensional (2D) potential flow problem to a quasi-2D potential flow approach by inclusion of streamline curvature and inclination effects following Fawer's theory. Flow of water in open channels and groundwater flow with a free surface can be characterized by potential functions and stream functions both obeying Laplace's 2D equation, provided there is isotropy and homogeneity. It is thus natural to expect the transfer of ideas from the open channel to the groundwater flow. A novel approximate model based on Fawer's theory for steady open channel flows with curved streamlines, coupled with Darcy's law, is proposed for groundwater flow with a free seepage surface. The seepage surface is described by a second-order differential equation which is applied to flow through both rectangular and trapezoidal dams, resulting in good agreement with the full 2D potential flow methods and test data.
DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933312585~frm=titlelink [article] Steady free-surface flow in porous media: generalized Dupuit-Fawer equations [texte imprimé] / Oscar Castro-Orgaz, Auteur . - 2011 . - pp. 55-63.
Hydraulique
Langues : Anglais (eng)
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 55-63
Mots-clés : Curvilinear flow Dam Flow net Open channel Seepage 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 : Steady free-surface flow in open channels may be analysed by the reduction of the two-dimensional (2D) potential flow problem to a quasi-2D potential flow approach by inclusion of streamline curvature and inclination effects following Fawer's theory. Flow of water in open channels and groundwater flow with a free surface can be characterized by potential functions and stream functions both obeying Laplace's 2D equation, provided there is isotropy and homogeneity. It is thus natural to expect the transfer of ideas from the open channel to the groundwater flow. A novel approximate model based on Fawer's theory for steady open channel flows with curved streamlines, coupled with Darcy's law, is proposed for groundwater flow with a free seepage surface. The seepage surface is described by a second-order differential equation which is applied to flow through both rectangular and trapezoidal dams, resulting in good agreement with the full 2D potential flow methods and test data.
DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933312585~frm=titlelink
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 64-72
Titre : Three-dimensional modelling of flow in sharp open-channel bends with vanes Type de document : texte imprimé Auteurs : Sang Soo Han, Auteur ; Biron, Pascale M., Auteur ; Amruthur S. Ramamurthy, Auteur Année de publication : 2011 Article en page(s) : pp. 64-72 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Flow separation Numerical simulation Open-channel bend Reynolds stress model Secondary flow Turbulence model Water surface 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 : Flow around a sharp open-channel bend is highly three-dimensional (3D) due to the combined effects of secondary flow, a large free surface variation and flow separation along the inner wall. Continuous vanes often used in closed curved conduits to generate a more uniform downstream flow were tested in the open channel using a 3D finite-volume model with a Reynolds stress turbulence model and the volume of fluid method for free surface prediction. The velocity field, turbulent kinetic energy and the extent of the flow separation zone were successfully validated against laboratory measurements for the no-vane case. The 3D simulations for one-vane and three-vane configurations reveal that vertical vanes are effective to reduce the secondary flow intensity and flow separation along the inner wall. The energy loss for bends with vanes is further slightly reduced compared to the no-vane case. The three-vane configuration is particularly efficient at creating uniform downstream flow.
DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933340662~frm=titlelink [article] Three-dimensional modelling of flow in sharp open-channel bends with vanes [texte imprimé] / Sang Soo Han, Auteur ; Biron, Pascale M., Auteur ; Amruthur S. Ramamurthy, Auteur . - 2011 . - pp. 64-72.
Hydraulique
Langues : Anglais (eng)
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 64-72
Mots-clés : Flow separation Numerical simulation Open-channel bend Reynolds stress model Secondary flow Turbulence model Water surface 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 : Flow around a sharp open-channel bend is highly three-dimensional (3D) due to the combined effects of secondary flow, a large free surface variation and flow separation along the inner wall. Continuous vanes often used in closed curved conduits to generate a more uniform downstream flow were tested in the open channel using a 3D finite-volume model with a Reynolds stress turbulence model and the volume of fluid method for free surface prediction. The velocity field, turbulent kinetic energy and the extent of the flow separation zone were successfully validated against laboratory measurements for the no-vane case. The 3D simulations for one-vane and three-vane configurations reveal that vertical vanes are effective to reduce the secondary flow intensity and flow separation along the inner wall. The energy loss for bends with vanes is further slightly reduced compared to the no-vane case. The three-vane configuration is particularly efficient at creating uniform downstream flow.
DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933340662~frm=titlelink
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 73-81
Titre : Water-surface oscillations in channels with axi-symmetric cavities Type de document : texte imprimé Auteurs : Tobias Meile, Auteur ; Boillat, Jean-Louis, Auteur ; Anton J. Schleiss, Auteur Année de publication : 2011 Article en page(s) : pp. 73-81 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Cavities Embayment Open channel flow Water-surface oscillation Strouhal 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 : Transverse or longitudinal movements of a water body are observed for flows along cavities, river embayments, groyne fields or harbours. They are significant for certain flow conditions and geometrical properties. To study the effect of large-scale roughness on banks, 36 geometries of axi-symmetric, rectangular cavities were investigated in a laboratory flume under subcritical, turbulent free surface flow conditions. Significant movements of the water body were detected. The frequency of these periodic movements, identified by level and velocity observations, is in agreement with the natural frequency of the water body in a rectangular basin assuming the first-order mode of sloshing. Major movements of the water body, which lead to significant and periodic oscillations of the water surface, are avoided by excluding Strouhal numbers near 0.42 and 0.84. For low aspect cavity ratios, the periodic water-surface oscillations are insignificant if the flow reattaches to the sidewalls of the widened channel reach.
DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933322200~frm=titlelink [article] Water-surface oscillations in channels with axi-symmetric cavities [texte imprimé] / Tobias Meile, Auteur ; Boillat, Jean-Louis, Auteur ; Anton J. Schleiss, Auteur . - 2011 . - pp. 73-81.
Hydraulique
Langues : Anglais (eng)
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 73-81
Mots-clés : Cavities Embayment Open channel flow Water-surface oscillation Strouhal 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 : Transverse or longitudinal movements of a water body are observed for flows along cavities, river embayments, groyne fields or harbours. They are significant for certain flow conditions and geometrical properties. To study the effect of large-scale roughness on banks, 36 geometries of axi-symmetric, rectangular cavities were investigated in a laboratory flume under subcritical, turbulent free surface flow conditions. Significant movements of the water body were detected. The frequency of these periodic movements, identified by level and velocity observations, is in agreement with the natural frequency of the water body in a rectangular basin assuming the first-order mode of sloshing. Major movements of the water body, which lead to significant and periodic oscillations of the water surface, are avoided by excluding Strouhal numbers near 0.42 and 0.84. For low aspect cavity ratios, the periodic water-surface oscillations are insignificant if the flow reattaches to the sidewalls of the widened channel reach.
DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933322200~frm=titlelink
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 82-89
Titre : An ordinary differential equation for velocity distribution and dip-phenomenon in open channel flows Type de document : texte imprimé Auteurs : Absi, Rafik, Auteur Année de publication : 2011 Article en page(s) : pp. 82-89 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Dip-phenomenon Eddy viscosity Log-wake law Open channel flows Ordinary differential equation Semi-analytical solution 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 : An ordinary differential equation (ODE) for velocity distribution in open channel flows is presented based on an analysis of the Reynolds-averaged Navier-Stokes equations and a log-wake modified eddy viscosity distribution. This proposed equation allows to predict the velocity-dip-phenomenon, i.e. the maximum velocity below the free surface. Two different degrees of approximations are presented, a semi-analytical solution of the proposed ODE, i.e. the full dip-modified-log-wake law (fDMLW-law) and a simple dip-modified-log-wake law (sDMLW-law). Velocity profiles of the two laws and the numerical solution of the ODE are compared with experimental data. This study shows that the dip correction is not efficient for a small Coles' parameter, accurate predictions require larger values. The sDMLW-law shows reasonable agreement and seems to be an interesting tool of intermediate accuracy. The fDMLW-law, with a parameter for dip-correction obtained from an estimation of dip positions, provides accurate velocity profiles.
DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933344782~frm=titlelink [article] An ordinary differential equation for velocity distribution and dip-phenomenon in open channel flows [texte imprimé] / Absi, Rafik, Auteur . - 2011 . - pp. 82-89.
Hydraulique
Langues : Anglais (eng)
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 82-89
Mots-clés : Dip-phenomenon Eddy viscosity Log-wake law Open channel flows Ordinary differential equation Semi-analytical solution 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 : An ordinary differential equation (ODE) for velocity distribution in open channel flows is presented based on an analysis of the Reynolds-averaged Navier-Stokes equations and a log-wake modified eddy viscosity distribution. This proposed equation allows to predict the velocity-dip-phenomenon, i.e. the maximum velocity below the free surface. Two different degrees of approximations are presented, a semi-analytical solution of the proposed ODE, i.e. the full dip-modified-log-wake law (fDMLW-law) and a simple dip-modified-log-wake law (sDMLW-law). Velocity profiles of the two laws and the numerical solution of the ODE are compared with experimental data. This study shows that the dip correction is not efficient for a small Coles' parameter, accurate predictions require larger values. The sDMLW-law shows reasonable agreement and seems to be an interesting tool of intermediate accuracy. The fDMLW-law, with a parameter for dip-correction obtained from an estimation of dip positions, provides accurate velocity profiles.
DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933344782~frm=titlelink
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 90-95
Titre : Scale effects of air entrained by hydraulic jumps within closed conduits Type de document : texte imprimé Auteurs : Joshua D. Mortensen, Auteur ; Steven L. Barfuss, Auteur ; Michael C. Johnson, Auteur Année de publication : 2011 Article en page(s) : pp. 90-95 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Air entrainment Closed conduit Hydraulic jump Scale effect Temperature effect 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 : While there has been a great deal of research in air entrainment at hydraulic jumps within closed conduits, limited research has specifically addressed size-scale effects. To determine the significance of these effects in closed conduits, air flow measurements were taken in four different-sized circular pipes with similar Froude numbers. Additionally, specific measurements were taken in one of the pipes with various water temperatures to identify any effects from changing fluid properties. The results indicated that the percentage of air entrainment was not affected by the pipe size if the full length of the hydraulic jump was contained within the pipe. For this condition, the data from four different pipes show that size-scale effects of air entrained into hydraulic jumps within closed conduits are negligible. However, air entrainment was significantly affected by water temperature.
DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933339566~frm=titlelink [article] Scale effects of air entrained by hydraulic jumps within closed conduits [texte imprimé] / Joshua D. Mortensen, Auteur ; Steven L. Barfuss, Auteur ; Michael C. Johnson, Auteur . - 2011 . - pp. 90-95.
Hydraulique
Langues : Anglais (eng)
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 90-95
Mots-clés : Air entrainment Closed conduit Hydraulic jump Scale effect Temperature effect 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 : While there has been a great deal of research in air entrainment at hydraulic jumps within closed conduits, limited research has specifically addressed size-scale effects. To determine the significance of these effects in closed conduits, air flow measurements were taken in four different-sized circular pipes with similar Froude numbers. Additionally, specific measurements were taken in one of the pipes with various water temperatures to identify any effects from changing fluid properties. The results indicated that the percentage of air entrainment was not affected by the pipe size if the full length of the hydraulic jump was contained within the pipe. For this condition, the data from four different pipes show that size-scale effects of air entrained into hydraulic jumps within closed conduits are negligible. However, air entrainment was significantly affected by water temperature.
DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933339566~frm=titlelink
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 96-104
Titre : Computational investigations of solid-liquid particle interaction in a two-phase flow around a ducted obstruction Type de document : texte imprimé Auteurs : Manabendra Pathak, Auteur Année de publication : 2011 Article en page(s) : pp. 96-104 Langues : Anglais (eng) Mots-clés : Algebraic slip mixture model Particle size Sediment transport Turbulence Two-phase 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 effect of bed obstruction on the dispersion of solid particles in a two-phase flow was numerically investigated. An algebraic slip mixture model was used to model this flow and the re-normalization group k-ε model to resolve flow turbulence. Computations were performed for three different sizes of solid particles to investigate their effect on turbulence modulation. Due to the obstruction, a distortion of the self-similar mean velocity profile was observed including the typical stratified dispersion of solid particles in the region comprising the stagnation and wake regions. Its length increases with particle size. The stagnation region is characterized by high preferential deposition of particles, whereas the wake region has a low concentration gradient. The effect of wake vortices on particle dispersion decreases as the particle size increases. Turbulence intensity increases with the particle size, whereas relative turbulence modulation was observed in complex flow regions for larger-sized particles.
DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933310251~frm=titlelink [article] Computational investigations of solid-liquid particle interaction in a two-phase flow around a ducted obstruction [texte imprimé] / Manabendra Pathak, Auteur . - 2011 . - pp. 96-104.
Langues : Anglais (eng)
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 96-104
Mots-clés : Algebraic slip mixture model Particle size Sediment transport Turbulence Two-phase 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 effect of bed obstruction on the dispersion of solid particles in a two-phase flow was numerically investigated. An algebraic slip mixture model was used to model this flow and the re-normalization group k-ε model to resolve flow turbulence. Computations were performed for three different sizes of solid particles to investigate their effect on turbulence modulation. Due to the obstruction, a distortion of the self-similar mean velocity profile was observed including the typical stratified dispersion of solid particles in the region comprising the stagnation and wake regions. Its length increases with particle size. The stagnation region is characterized by high preferential deposition of particles, whereas the wake region has a low concentration gradient. The effect of wake vortices on particle dispersion decreases as the particle size increases. Turbulence intensity increases with the particle size, whereas relative turbulence modulation was observed in complex flow regions for larger-sized particles.
DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933310251~frm=titlelink
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 105-112
Titre : Time-dependent local scour downstream of positive-step stilling basins Type de document : texte imprimé Auteurs : Giuseppe Oliveto, Auteur ; Victor Comuniello, Auteur ; Trupti Bulbule, Auteur Année de publication : 2011 Article en page(s) : pp. 105-112 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Densimetric Froude number Hydraulic jet Scour Stilling basins Time dependence 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 : Local scour downstream of spillways is an important problem in hydraulic engineering. The objective of this experimental study was to investigate the temporal evolution of local scour downstream of a spillway followed by a positive-step stilling basin. Experiments were conducted in a rectangular channel using four different sediments for the mobile bed. Additional tests concerned the incipient motion of sediment particles. The main parameters governing the scour process were found to be the tailwater densimetric Froude number and the relative tailwater depth. No experimental evidence was found on similar scour profiles. Scour starts at a much reduced tailwater densimetric Froude number when compared with Shields. The temporal variation of the scour hole geometry was estimated using simple power-law equations relating the scour geometry to the controlling scour parameters.
DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933312376~frm=titlelink [article] Time-dependent local scour downstream of positive-step stilling basins [texte imprimé] / Giuseppe Oliveto, Auteur ; Victor Comuniello, Auteur ; Trupti Bulbule, Auteur . - 2011 . - pp. 105-112.
Hydraulique
Langues : Anglais (eng)
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 105-112
Mots-clés : Densimetric Froude number Hydraulic jet Scour Stilling basins Time dependence 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 : Local scour downstream of spillways is an important problem in hydraulic engineering. The objective of this experimental study was to investigate the temporal evolution of local scour downstream of a spillway followed by a positive-step stilling basin. Experiments were conducted in a rectangular channel using four different sediments for the mobile bed. Additional tests concerned the incipient motion of sediment particles. The main parameters governing the scour process were found to be the tailwater densimetric Froude number and the relative tailwater depth. No experimental evidence was found on similar scour profiles. Scour starts at a much reduced tailwater densimetric Froude number when compared with Shields. The temporal variation of the scour hole geometry was estimated using simple power-law equations relating the scour geometry to the controlling scour parameters.
DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933312376~frm=titlelink
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 113-116
Titre : Comparison between empirical formulae of intake vortices Type de document : texte imprimé Auteurs : Yingkui Wang, Auteur ; Chunbo Jiang, Auteur ; Dongfang Liang, Auteur Année de publication : 2011 Article en page(s) : pp. 113-116 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Air-core vortex Axial symmetric flow Hydraulic intake Navier-Stokes equations Vortex 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 hydrodynamic properties of free surface vortices at hydraulic intakes were investigated. Based on the axisymmetric Navier-Stokes equations and empirical assumptions, two sets of formulations for the velocity distributions and the free surface profiles are proposed and validated against measurements available in the literature. Compared with previous formulae, the modifications based on Mih's formula are found to greatly improve the agreement with the experimental data. Physical model tests were also conducted to study the intake vortex of the Xiluodu hydroelectric project in China. The proposed velocity distribution formula was applied to the solid boundary as considered by the method of images. A good agreement was again observed between the prediction and the measurements.
DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933343847~frm=titlelink [article] Comparison between empirical formulae of intake vortices [texte imprimé] / Yingkui Wang, Auteur ; Chunbo Jiang, Auteur ; Dongfang Liang, Auteur . - 2011 . - pp. 113-116.
Hydraulique
Langues : Anglais (eng)
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 113-116
Mots-clés : Air-core vortex Axial symmetric flow Hydraulic intake Navier-Stokes equations Vortex 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 hydrodynamic properties of free surface vortices at hydraulic intakes were investigated. Based on the axisymmetric Navier-Stokes equations and empirical assumptions, two sets of formulations for the velocity distributions and the free surface profiles are proposed and validated against measurements available in the literature. Compared with previous formulae, the modifications based on Mih's formula are found to greatly improve the agreement with the experimental data. Physical model tests were also conducted to study the intake vortex of the Xiluodu hydroelectric project in China. The proposed velocity distribution formula was applied to the solid boundary as considered by the method of images. A good agreement was again observed between the prediction and the measurements.
DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933343847~frm=titlelink
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 117-121
Titre : Critical submergence for multiple pipe intakes by the potential flow solution Type de document : texte imprimé Auteurs : Yildirim, Nevzat, Auteur ; Akay Huseyın, Auteur ; Kerem Tastan, Auteur Année de publication : 2011 Article en page(s) : pp. 117-121 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Critical submergence Intake Potential solution Sump Vortex 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 critical submergence for a group of multiple pipe intakes is predicted using a potential flow solution. Experimental and theoretical results indicate that the critical submergence is considerably affected by the flows and relative positions of the intakes within the group. If there exists an imposed or induced circulation of sufficient strength, an air-core vortex may develop without intake discharge. The agreement between the potential solution and the experimental results related to the group of four intakes is satisfactory. The method presented herein can also be used for multiple intakes located in general flow and geometrical conditions, including still-water or circulation-imposed flows.
DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933343823~frm=titlelink [article] Critical submergence for multiple pipe intakes by the potential flow solution [texte imprimé] / Yildirim, Nevzat, Auteur ; Akay Huseyın, Auteur ; Kerem Tastan, Auteur . - 2011 . - pp. 117-121.
Hydraulique
Langues : Anglais (eng)
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 117-121
Mots-clés : Critical submergence Intake Potential solution Sump Vortex 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 critical submergence for a group of multiple pipe intakes is predicted using a potential flow solution. Experimental and theoretical results indicate that the critical submergence is considerably affected by the flows and relative positions of the intakes within the group. If there exists an imposed or induced circulation of sufficient strength, an air-core vortex may develop without intake discharge. The agreement between the potential solution and the experimental results related to the group of four intakes is satisfactory. The method presented herein can also be used for multiple intakes located in general flow and geometrical conditions, including still-water or circulation-imposed flows.
DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933343823~frm=titlelink
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 122-126
Titre : Comparison of macroturbulence measured using decomposition of PIV, ADV and LSPIV data Type de document : texte imprimé Auteurs : James F. Fox, Auteur ; Brian J. Belcher, Auteur Année de publication : 2011 Article en page(s) : pp. 122-126 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Gravel-bed Open channel Scales of turbulence Velocimetry 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 : Visualization and length-scale estimates are provided for turbulence in open channel flow over a gravel-bed. Results obtained using the digital particle image velocimetry (PIV) followed by post-processing with proper orthogonal decomposition showed higher and lower velocity regions aligned along a stagnation plane extending from the bed at approximately a 20° angle. Periodicity of second and fourth quadrant events equalled 0.20 s and agreed well with the outer variable defined bursting period. Normalized turbulence length scales were measured after performing the decomposition of the turbulent fields collected with various instrumentation techniques. Acoustic Doppler velocimetry and PIV had turbulence length scales equal to the flow depth, and the good agreement highlights the ability of the former to estimate length scales in streams. Large scale PIV provided length scales equal to 1.5 times the flow depth, but care should be used if directly inferring scales of macroturbulence from the free-surface.
DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933311934~frm=titlelink [article] Comparison of macroturbulence measured using decomposition of PIV, ADV and LSPIV data [texte imprimé] / James F. Fox, Auteur ; Brian J. Belcher, Auteur . - 2011 . - pp. 122-126.
Hydraulique
Langues : Anglais (eng)
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 122-126
Mots-clés : Gravel-bed Open channel Scales of turbulence Velocimetry 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 : Visualization and length-scale estimates are provided for turbulence in open channel flow over a gravel-bed. Results obtained using the digital particle image velocimetry (PIV) followed by post-processing with proper orthogonal decomposition showed higher and lower velocity regions aligned along a stagnation plane extending from the bed at approximately a 20° angle. Periodicity of second and fourth quadrant events equalled 0.20 s and agreed well with the outer variable defined bursting period. Normalized turbulence length scales were measured after performing the decomposition of the turbulent fields collected with various instrumentation techniques. Acoustic Doppler velocimetry and PIV had turbulence length scales equal to the flow depth, and the good agreement highlights the ability of the former to estimate length scales in streams. Large scale PIV provided length scales equal to 1.5 times the flow depth, but care should be used if directly inferring scales of macroturbulence from the free-surface.
DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.informaworld.com/smpp/content~db=all~content=a933311934~frm=titlelink
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