Documents disponibles écrits par cet auteur

Effect of particle size on the characteristics of sand jets in water / Amir Hossein Azimi in Journal of engineering mechanics, Vol. 137 N° 12 (Decembre 2011) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 137 N° 12 (Decembre 2011) . - pp.822-834 Titre : Effect of particle size on the characteristics of sand jets in water Type de document : texte imprimé Auteurs : Amir Hossein Azimi, Auteur ; David Z. Zhu, Auteur ; Nallamuthu Rajaratnam, Auteur Année de publication : 2012 Article en page(s) : pp.822-834 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Particle  size  Turbulence  Numerical  models  Computational  fluid  dynamics  technique Résumé : Sand jets in water have extensive engineering applications. A detailed numerical modeling of sand jets in water was conducted at high initial sand concentration using a commercial computational fluid dynamics package (ANSYS CFX 11.0). The results of the numerical simulation were first compared with some recent laboratory experiments. Simulations were then conducted to investigate the effect of sand particle sizes on velocity distribution, concentration profile, and turbulent properties. Turbulent flow characteristics, such as turbulent kinetic energy, turbulence intensity, rate of energy dissipation, and turbulent eddy frequency, were evaluated and the trend compared with the previous studies in the literature. The location of maximum kinetic energy was found to be independent of particle size. The turbulent kinetic energy and rate of dissipation of the water phase decrease with increasing particle size. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.org/emo/resource/1/jenmdt/v137/i12/p822_s1?isAuthorized=no [article] Effect of particle size on the characteristics of sand jets in water [texte imprimé] / Amir Hossein Azimi, Auteur ; David Z. Zhu, Auteur ; Nallamuthu Rajaratnam, Auteur . - 2012 . - pp.822-834. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 137 N° 12 (Decembre 2011) . - pp.822-834 Mots-clés : Particle  size  Turbulence  Numerical  models  Computational  fluid  dynamics  technique Résumé : Sand jets in water have extensive engineering applications. A detailed numerical modeling of sand jets in water was conducted at high initial sand concentration using a commercial computational fluid dynamics package (ANSYS CFX 11.0). The results of the numerical simulation were first compared with some recent laboratory experiments. Simulations were then conducted to investigate the effect of sand particle sizes on velocity distribution, concentration profile, and turbulent properties. Turbulent flow characteristics, such as turbulent kinetic energy, turbulence intensity, rate of energy dissipation, and turbulent eddy frequency, were evaluated and the trend compared with the previous studies in the literature. The location of maximum kinetic energy was found to be independent of particle size. The turbulent kinetic energy and rate of dissipation of the water phase decrease with increasing particle size. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.org/emo/resource/1/jenmdt/v137/i12/p822_s1?isAuthorized=no

Jet diffusion inside a confined chamber / G. Adriana Camino in Journal of hydraulic research, Vol. 50 N° 1 (Janvier/Février 2012) 

Public ISBD [article]  in Journal of hydraulic research > Vol. 50 N° 1 (Janvier/Février 2012) . - pp. 121-128 Titre : Jet diffusion inside a confined chamber Type de document : texte imprimé Auteurs : G. Adriana Camino, Auteur ; David Z. Zhu, Auteur ; Nallamuthu Rajaratnam, Auteur Année de publication : 2012 Article en page(s) : pp. 121-128 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Confined  jet  Energy  dissipation  Hydraulics  Jet  diffusion  Recirculating  flow Résumé : Assessing the amount of energy dissipation that can be achieved by simple jet diffusion in a confined environment has considerable practical importance. Previous works on jets in confined enclosures have indicated that the entrainment of a recirculating fluid greatly enhances the dissipation of the inflow kinetic energy and reduces the length of the potential core. In the present experimental work, a vertical jet issuing into a rectangular chamber is investigated under two types of confinement and three locations of entry. Detailed velocity measurements for an eccentric jet are obtained to assess the evolution of the axial jet centreline velocity and the turbulent characteristics. These results are compared with classical jet behaviour and jets under other confined conditions. A method to predict the energy dissipation attained by jet diffusion in a confined chamber is also proposed. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.650423 [article] Jet diffusion inside a confined chamber [texte imprimé] / G. Adriana Camino, Auteur ; David Z. Zhu, Auteur ; Nallamuthu Rajaratnam, Auteur . - 2012 . - pp. 121-128. Hydraulique Langues : Anglais (eng) in Journal of hydraulic research > Vol. 50 N° 1 (Janvier/Février 2012) . - pp. 121-128 Mots-clés : Confined  jet  Energy  dissipation  Hydraulics  Jet  diffusion  Recirculating  flow Résumé : Assessing the amount of energy dissipation that can be achieved by simple jet diffusion in a confined environment has considerable practical importance. Previous works on jets in confined enclosures have indicated that the entrainment of a recirculating fluid greatly enhances the dissipation of the inflow kinetic energy and reduces the length of the potential core. In the present experimental work, a vertical jet issuing into a rectangular chamber is investigated under two types of confinement and three locations of entry. Detailed velocity measurements for an eccentric jet are obtained to assess the evolution of the axial jet centreline velocity and the turbulent characteristics. These results are compared with classical jet behaviour and jets under other confined conditions. A method to predict the energy dissipation attained by jet diffusion in a confined chamber is also proposed. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.650423

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