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Scour upstream of a circular orifice under constant head / David N. Powell 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. 28-34 Titre : Scour upstream of a circular orifice under constant head Type de document : texte imprimé Auteurs : David N. Powell, Auteur ; Abdul A. Khan, Auteur Année de publication : 2012 Article en page(s) : pp. 28-34 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Circular  orifice  Local  scour  Scour  mechanism  Scour  shape  Vortex  action Résumé : The transport mechanism as well as the extent and the shape of the scour upstream of a circular orifice is investigated under steady flow conditions for different sediment sizes and heads on the orifice. The main mechanism of sediment transport is found to be vortex-related, appearing randomly within the scour hole. The scour length, maximum scour width, and maximum scour depth are evaluated for various sediment sizes and under different heads on the orifice. The non-dimensional scour depth profiles along the orifice centreline are found to be similar. The non-dimensional scour depth profiles across the width of the scour hole at various locations upstream of the orifice are found to be similar as well. The flow characteristics related to the scaled centreline longitudinal velocity and the scaled position of the maximum longitudinal velocity are found to approach those for the unbounded orifice at the equilibrium scour condition. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.637821 [article] Scour upstream of a circular orifice under constant head [texte imprimé] / David N. Powell, Auteur ; Abdul A. Khan, Auteur . - 2012 . - pp. 28-34. Hydraulique Langues : Anglais (eng) in Journal of hydraulic research > Vol. 50 N° 1 (Janvier/Février 2012) . - pp. 28-34 Mots-clés : Circular  orifice  Local  scour  Scour  mechanism  Scour  shape  Vortex  action Résumé : The transport mechanism as well as the extent and the shape of the scour upstream of a circular orifice is investigated under steady flow conditions for different sediment sizes and heads on the orifice. The main mechanism of sediment transport is found to be vortex-related, appearing randomly within the scour hole. The scour length, maximum scour width, and maximum scour depth are evaluated for various sediment sizes and under different heads on the orifice. The non-dimensional scour depth profiles along the orifice centreline are found to be similar. The non-dimensional scour depth profiles across the width of the scour hole at various locations upstream of the orifice are found to be similar as well. The flow characteristics related to the scaled centreline longitudinal velocity and the scaled position of the maximum longitudinal velocity are found to approach those for the unbounded orifice at the equilibrium scour condition. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.637821