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Effect of upstream shear on flow and heat (Mass) transfer over a flat plate. Part I, Velocity measurements / K. Ghosh in Journal of heat transfer, Vol. 132 N° 10 (Octobre 2010) 

Public ISBD [article]  in Journal of heat transfer > Vol. 132 N° 10 (Octobre 2010) . - pp. [101701-1/7] Titre : Effect of upstream shear on flow and heat (Mass) transfer over a flat plate. Part I, Velocity measurements Type de document : texte imprimé Auteurs : K. Ghosh, Auteur ; R. J. Goldstein, Auteur Année de publication : 2010 Article en page(s) : pp. [101701-1/7] Note générale : Physique Langues : Anglais (eng) Mots-clés : Turbulent  flow  Wall  shear  Clauser  technique  Boundary  layer  Scaling  laws Index. décimale : 536 Chaleur. Thermodynamique Résumé : A parametric study investigates the effects of wall shear on a two-dimensional turbulent boundary layer. A belt translating along the direction of the flow imparts the shear. Velocity measurements are performed at 12 streamwise locations with four surface-to-freestream velocity ratios (0, 0.38, 0.52, and 0.65) and a momentum-based Reynolds number between 770 and 1776. The velocity data indicate that the location of the “virtual origin” of the turbulent boundary layer “moves” downstream toward the trailing edge of the belt with increasing surface velocity. The highest belt velocity ratio (0.65) results in the removal of the “inner” region of the boundary layer. Measurements of the streamwise turbulent kinetic energy show an inner scaling at locations upstream and downstream of the belt, and the formation of a new self-similar structure on the moving surface itself. Good agreement is observed for the variation in the shape factor (H) and the skin friction coefficient (cf) with the previous studies. The distribution of the energy spectrum downstream of the belt indicates peak values concentrated around 1 kHz for the stationary belt case in the near wall region (30 DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...] [article] Effect of upstream shear on flow and heat (Mass) transfer over a flat plate. Part I, Velocity measurements [texte imprimé] / K. Ghosh, Auteur ; R. J. Goldstein, Auteur . - 2010 . - pp. [101701-1/7]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 132 N° 10 (Octobre 2010) . - pp. [101701-1/7] Mots-clés : Turbulent  flow  Wall  shear  Clauser  technique  Boundary  layer  Scaling  laws Index. décimale : 536 Chaleur. Thermodynamique Résumé : A parametric study investigates the effects of wall shear on a two-dimensional turbulent boundary layer. A belt translating along the direction of the flow imparts the shear. Velocity measurements are performed at 12 streamwise locations with four surface-to-freestream velocity ratios (0, 0.38, 0.52, and 0.65) and a momentum-based Reynolds number between 770 and 1776. The velocity data indicate that the location of the “virtual origin” of the turbulent boundary layer “moves” downstream toward the trailing edge of the belt with increasing surface velocity. The highest belt velocity ratio (0.65) results in the removal of the “inner” region of the boundary layer. Measurements of the streamwise turbulent kinetic energy show an inner scaling at locations upstream and downstream of the belt, and the formation of a new self-similar structure on the moving surface itself. Good agreement is observed for the variation in the shape factor (H) and the skin friction coefficient (cf) with the previous studies. The distribution of the energy spectrum downstream of the belt indicates peak values concentrated around 1 kHz for the stationary belt case in the near wall region (30 DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...]

Effect of upstream shear on flow and heat (Mass) transfer over a flat plate. Part II, Mass transfer measurements / K. Ghosh in Journal of heat transfer, Vol. 132 N° 10 (Octobre 2010) 

Public ISBD [article]  in Journal of heat transfer > Vol. 132 N° 10 (Octobre 2010) . - pp. [101702-1/6] Titre : Effect of upstream shear on flow and heat (Mass) transfer over a flat plate. Part II, Mass transfer measurements Type de document : texte imprimé Auteurs : K. Ghosh, Auteur ; R. J. Goldstein, Auteur Année de publication : 2010 Article en page(s) : pp. [101702-1/6] Note générale : Physique Langues : Anglais (eng) Mots-clés : Heat/mass  transfer  analogy  Naphthalene  sublimation  Turbulent  flow  Wall  motion  Boundary  layer  Constant  temperature  Constant  concentration Index. décimale : 536 Chaleur. Thermodynamique Résumé : Mass transfer measurements on a flat plate downstream of a belt moving in the same direction of the freestream study the effect of the upstream shear on the heat (mass) transfer for four belt-freestream velocity ratios. With an increase in this ratio, the “virtual origin” of the turbulent boundary layer “moves” downstream toward the trailing edge of the belt. This is verified from the variation of the Stanton number versus the Reynolds number plots. As the “inner” region of the boundary layer is removed for a belt speed of uw=10 m/s (freestream velocity uin[approximate]15.4 m/s), a corresponding local minimum in the variation of the Stanton number is observed. Downstream of this minimum, the characteristics of the turbulent boundary layer are restored and the data fall back on the empirical variation of Stanton with Reynolds number. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...] [article] Effect of upstream shear on flow and heat (Mass) transfer over a flat plate. Part II, Mass transfer measurements [texte imprimé] / K. Ghosh, Auteur ; R. J. Goldstein, Auteur . - 2010 . - pp. [101702-1/6]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 132 N° 10 (Octobre 2010) . - pp. [101702-1/6] Mots-clés : Heat/mass  transfer  analogy  Naphthalene  sublimation  Turbulent  flow  Wall  motion  Boundary  layer  Constant  temperature  Constant  concentration Index. décimale : 536 Chaleur. Thermodynamique Résumé : Mass transfer measurements on a flat plate downstream of a belt moving in the same direction of the freestream study the effect of the upstream shear on the heat (mass) transfer for four belt-freestream velocity ratios. With an increase in this ratio, the “virtual origin” of the turbulent boundary layer “moves” downstream toward the trailing edge of the belt. This is verified from the variation of the Stanton number versus the Reynolds number plots. As the “inner” region of the boundary layer is removed for a belt speed of uw=10 m/s (freestream velocity uin[approximate]15.4 m/s), a corresponding local minimum in the variation of the Stanton number is observed. Downstream of this minimum, the characteristics of the turbulent boundary layer are restored and the data fall back on the empirical variation of Stanton with Reynolds number. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...]