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Benthic and interfacial mixing in a strongly-stratified estuary / Arthur Simanjuntak in Journal of hydraulic research, Vol. 49 N° 6 (Novembre/Décembre 2011) 

Public ISBD [article]  in Journal of hydraulic research > Vol. 49 N° 6 (Novembre/Décembre 2011) . - pp. 791-798 Titre : Benthic and interfacial mixing in a strongly-stratified estuary Type de document : texte imprimé Auteurs : Arthur Simanjuntak, Auteur ; Imberger, Jörg, Auteur ; Keisuke Nakayama, Auteur Année de publication : 2012 Article en page(s) : pp. 791-798 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Down-gradient  flux  Estuary  Richardson  number  Shear  Turbulent  closure 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 : Tone River is a shallow, tidal estuary with a controllable upstream freshwater discharge via a barrage. The mixing characteristics in the benthic and interfacial regions of the Tone River estuary were investigated during a time window of maximum freshwater discharge and high shear, using temperature and velocity microstructure measurements. Although the production of turbulent kinetic energy from mean shear was high throughout the water column, the intermittency of both up- and down-gradient buoyancy fluxes resulted in negligible net down-gradient mixing. These opposing fluxes were incorporated into a turbulent closure scheme by using the concept of percentage down-gradient flux. A comparison of vertical diffusivity from two alternative closures suggests that the stratification imposed a length scale limitation on the vertical turbulent excursions that proved crucial for the transition region between the benthic and interfacial regions; it is argued that a Richardson-number based closure is both conceptually and practically adequate to represent the effect of length-scale limitation and percentage down-gradient flux. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.607304 [article] Benthic and interfacial mixing in a strongly-stratified estuary [texte imprimé] / Arthur Simanjuntak, Auteur ; Imberger, Jörg, Auteur ; Keisuke Nakayama, Auteur . - 2012 . - pp. 791-798. Hydraulique Langues : Anglais (eng) in Journal of hydraulic research > Vol. 49 N° 6 (Novembre/Décembre 2011) . - pp. 791-798 Mots-clés : Down-gradient  flux  Estuary  Richardson  number  Shear  Turbulent  closure 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 : Tone River is a shallow, tidal estuary with a controllable upstream freshwater discharge via a barrage. The mixing characteristics in the benthic and interfacial regions of the Tone River estuary were investigated during a time window of maximum freshwater discharge and high shear, using temperature and velocity microstructure measurements. Although the production of turbulent kinetic energy from mean shear was high throughout the water column, the intermittency of both up- and down-gradient buoyancy fluxes resulted in negligible net down-gradient mixing. These opposing fluxes were incorporated into a turbulent closure scheme by using the concept of percentage down-gradient flux. A comparison of vertical diffusivity from two alternative closures suggests that the stratification imposed a length scale limitation on the vertical turbulent excursions that proved crucial for the transition region between the benthic and interfacial regions; it is argued that a Richardson-number based closure is both conceptually and practically adequate to represent the effect of length-scale limitation and percentage down-gradient flux. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.607304