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Experimental measurement of laminar axisymmetric flow through confined annular geometries with sudden inward expansion / Afshin Goharzadeh in Transactions of the ASME . Journal of fluids engineering, Vol. 131 N° 12 (Décembre 2009) 

Public ISBD [article]  in Transactions of the ASME . Journal of fluids engineering > Vol. 131 N° 12 (Décembre 2009) . - 04 p. Titre : Experimental measurement of laminar axisymmetric flow through confined annular geometries with sudden inward expansion Type de document : texte imprimé Auteurs : Afshin Goharzadeh, Auteur ; Peter Rodgers, Auteur Année de publication : 2010 Article en page(s) : 04 p. Note générale : fluids engineering Langues : Anglais (eng) Mots-clés : flow  (dynamics);  measurement;  eddies  (fluid  dynamics);  Reynolds  number;  laminar  flow;  particulate  matter Résumé : In this paper, separating and reattaching aqueous laminar flows produced by a sudden inward expansion within confined annular geometries are experimentally studied. The test geometries are based on a previous numerical study. The fluid flow structure at the expansion region is experimentally characterized using particle image velocimetry combined with refractive index matching. The detailed measurements of the velocity field, reattachment length, and relative eddy intensity are obtained for two different expansion ratios, 1.4 and 1.6. For both expansion ratios, the reattachment length is found to vary nonlinearly with the Reynolds number (50 En ligne : http://fluidsengineering.asmedigitalcollection.asme.org/issue.aspx?journalid=122 [...] [article] Experimental measurement of laminar axisymmetric flow through confined annular geometries with sudden inward expansion [texte imprimé] / Afshin Goharzadeh, Auteur ; Peter Rodgers, Auteur . - 2010 . - 04 p. fluids engineering Langues : Anglais (eng) in Transactions of the ASME . Journal of fluids engineering > Vol. 131 N° 12 (Décembre 2009) . - 04 p. Mots-clés : flow  (dynamics);  measurement;  eddies  (fluid  dynamics);  Reynolds  number;  laminar  flow;  particulate  matter Résumé : In this paper, separating and reattaching aqueous laminar flows produced by a sudden inward expansion within confined annular geometries are experimentally studied. The test geometries are based on a previous numerical study. The fluid flow structure at the expansion region is experimentally characterized using particle image velocimetry combined with refractive index matching. The detailed measurements of the velocity field, reattachment length, and relative eddy intensity are obtained for two different expansion ratios, 1.4 and 1.6. For both expansion ratios, the reattachment length is found to vary nonlinearly with the Reynolds number (50 En ligne : http://fluidsengineering.asmedigitalcollection.asme.org/issue.aspx?journalid=122 [...]

Influence of gas-liquid two-phase intermittent flow on hydraulic sand dune migration in horizontal pipelines / Afshin Goharzadeh in Transactions of the ASME . Journal of fluids engineering, Vol. 132 N° 7 (Juillet 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of fluids engineering > Vol. 132 N° 7 (Juillet 2010) . - 07 p. Titre : Influence of gas-liquid two-phase intermittent flow on hydraulic sand dune migration in horizontal pipelines Type de document : texte imprimé Auteurs : Afshin Goharzadeh, Auteur ; Peter Rodgers, Auteur ; Chokri Touati, Auteur Année de publication : 2010 Article en page(s) : 07 p. Note générale : fluids engineering Langues : Anglais (eng) Mots-clés : flow  (dynamics);  sands;  particulate  matter;  pipelines;  pipes;  mixtures;  slug;  water Résumé : This paper presents an experimental study of three-phase flows (air-water-sand) inside a horizontal pipe. The results obtained aim to enhance the fundamental understanding of sand transportation due to saltation in the presence of a gas-liquid two-phase intermittent flow. Sand dune pitch, length, height, and front velocity were measured using high-speed video photography. Four flow compositions with differing gas ratios, including hydraulic conveying, were assessed for sand transportation, having the same mixture velocity. For the test conditions under analysis, it was found that the gas ratio did not affect the average dune front velocity. However, for intermittent flows, the sand bed was transported further downstream relative to hydraulic conveying. It was also observed that the slug body significantly influences sand particle mobility. The physical mechanism of sand transportation was found to be discontinuous with intermittent flows. The sand dune local velocity (within the slug body) was measured to be three times higher than the averaged dune velocities, due to turbulent enhancement within the slug body. DEWEY : 620.1 ISSN : 0098-2202 En ligne : http://fluidsengineering.asmedigitalcollection.asme.org/Issue.aspx?issueID=27423 [...] [article] Influence of gas-liquid two-phase intermittent flow on hydraulic sand dune migration in horizontal pipelines [texte imprimé] / Afshin Goharzadeh, Auteur ; Peter Rodgers, Auteur ; Chokri Touati, Auteur . - 2010 . - 07 p. fluids engineering Langues : Anglais (eng) in Transactions of the ASME . Journal of fluids engineering > Vol. 132 N° 7 (Juillet 2010) . - 07 p. Mots-clés : flow  (dynamics);  sands;  particulate  matter;  pipelines;  pipes;  mixtures;  slug;  water Résumé : This paper presents an experimental study of three-phase flows (air-water-sand) inside a horizontal pipe. The results obtained aim to enhance the fundamental understanding of sand transportation due to saltation in the presence of a gas-liquid two-phase intermittent flow. Sand dune pitch, length, height, and front velocity were measured using high-speed video photography. Four flow compositions with differing gas ratios, including hydraulic conveying, were assessed for sand transportation, having the same mixture velocity. For the test conditions under analysis, it was found that the gas ratio did not affect the average dune front velocity. However, for intermittent flows, the sand bed was transported further downstream relative to hydraulic conveying. It was also observed that the slug body significantly influences sand particle mobility. The physical mechanism of sand transportation was found to be discontinuous with intermittent flows. The sand dune local velocity (within the slug body) was measured to be three times higher than the averaged dune velocities, due to turbulent enhancement within the slug body. DEWEY : 620.1 ISSN : 0098-2202 En ligne : http://fluidsengineering.asmedigitalcollection.asme.org/Issue.aspx?issueID=27423 [...]