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Non-uniformity and layering in sediment transport modelling 1 / Michael Tritthart in Journal of hydraulic research, Vol. 49 N° 3 (Mai/Juin 2011) 

Public ISBD [article]  in Journal of hydraulic research > Vol. 49 N° 3 (Mai/Juin 2011) . - pp. 325-334 Titre : Non-uniformity and layering in sediment transport modelling 1 : flume simulations Type de document : texte imprimé Auteurs : Michael Tritthart, Auteur ; Bernhard Schober, Auteur ; Helmut Habersack, Auteur Année de publication : 2011 Article en page(s) : pp. 325-334 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Bed  load  Empirical  equation  Flume  experiment  Numerical  model  Sediment  transport 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 : The development and validation of an integrated numerical sediment transport model capable of solving both uniform and non-uniform transport equations while calculating grain size distributions is presented. The model is coupled with external hydrodynamic codes which provide flow field and bed shear stress patterns. Transport equations are solved for an unlimited number of sediment size fractions. Two validation experiments involving unsteady flow in a channel bend and steady flow in a flume with lateral contraction were considered. Good agreement with measured bed deformations was found for non-uniform calculations with an exchange layer, whereas both uniform and non-uniform computations without the exchange layer resulted in comparably larger differences. In the channel bend experiment, the presence of an exchange layer was essential for achieving accurate modelling results, while its role was less pronounced in the lateral contraction experiment. Moreover, the sorting coefficient of the bed material was found to be a suitable indicator for estimating the applicability of uniform transport equations. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.583528 [article] Non-uniformity and layering in sediment transport modelling 1 : flume simulations [texte imprimé] / Michael Tritthart, Auteur ; Bernhard Schober, Auteur ; Helmut Habersack, Auteur . - 2011 . - pp. 325-334. Hydraulique Langues : Anglais (eng) in Journal of hydraulic research > Vol. 49 N° 3 (Mai/Juin 2011) . - pp. 325-334 Mots-clés : Bed  load  Empirical  equation  Flume  experiment  Numerical  model  Sediment  transport 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 : The development and validation of an integrated numerical sediment transport model capable of solving both uniform and non-uniform transport equations while calculating grain size distributions is presented. The model is coupled with external hydrodynamic codes which provide flow field and bed shear stress patterns. Transport equations are solved for an unlimited number of sediment size fractions. Two validation experiments involving unsteady flow in a channel bend and steady flow in a flume with lateral contraction were considered. Good agreement with measured bed deformations was found for non-uniform calculations with an exchange layer, whereas both uniform and non-uniform computations without the exchange layer resulted in comparably larger differences. In the channel bend experiment, the presence of an exchange layer was essential for achieving accurate modelling results, while its role was less pronounced in the lateral contraction experiment. Moreover, the sorting coefficient of the bed material was found to be a suitable indicator for estimating the applicability of uniform transport equations. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.583528

Non-uniformity and layering in sediment transport modelling 2 / Michael Tritthart in Journal of hydraulic research, Vol. 49 N° 3 (Mai/Juin 2011) 

Public ISBD [article]  in Journal of hydraulic research > Vol. 49 N° 3 (Mai/Juin 2011) . - pp. 335-344 Titre : Non-uniformity and layering in sediment transport modelling 2 : river application Type de document : texte imprimé Auteurs : Michael Tritthart, Auteur ; Marcel Liedermann, Auteur ; Bernhard Schober, Auteur Année de publication : 2011 Article en page(s) : pp. 335-344 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Bed-load  Danube  River  Empirical  equation  Numerical  model  River  flow  Sediment  transport 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 : The objectives of this research are to verify a numerical sediment transport model based on field data from a reach of the Austrian Danube River, to identify the influence of non-uniform bed-load transport modelling and the selected bed schematization on the simulation results and to investigate the cause and the numerical reproducibility of spatio-temporal variations found in field data. Simulation results based on variants of the transport equation by Meyer-Peter and Müller were compared to basket sampler and radio tracer stone observations. The best agreement was obtained for a non-uniform formulation with an exchange layer, while the uniform formulation of the transport equation underestimated the transport rates for discharges lower than the mean flow since it predicts a later onset of bed-load transport. The consideration of an exchange layer in the numerical code led to the prediction of bed-load sheets due to sorting waves, allowing the model to account for the spatio-temporal variability of field data. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.583487 [article] Non-uniformity and layering in sediment transport modelling 2 : river application [texte imprimé] / Michael Tritthart, Auteur ; Marcel Liedermann, Auteur ; Bernhard Schober, Auteur . - 2011 . - pp. 335-344. Hydraulique Langues : Anglais (eng) in Journal of hydraulic research > Vol. 49 N° 3 (Mai/Juin 2011) . - pp. 335-344 Mots-clés : Bed-load  Danube  River  Empirical  equation  Numerical  model  River  flow  Sediment  transport 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 : The objectives of this research are to verify a numerical sediment transport model based on field data from a reach of the Austrian Danube River, to identify the influence of non-uniform bed-load transport modelling and the selected bed schematization on the simulation results and to investigate the cause and the numerical reproducibility of spatio-temporal variations found in field data. Simulation results based on variants of the transport equation by Meyer-Peter and Müller were compared to basket sampler and radio tracer stone observations. The best agreement was obtained for a non-uniform formulation with an exchange layer, while the uniform formulation of the transport equation underestimated the transport rates for discharges lower than the mean flow since it predicts a later onset of bed-load transport. The consideration of an exchange layer in the numerical code led to the prediction of bed-load sheets due to sorting waves, allowing the model to account for the spatio-temporal variability of field data. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.583487