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Coherent structures around isolated spur dikes at various approach flow angles / Mete Koken 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. 736-743 Titre : Coherent structures around isolated spur dikes at various approach flow angles Type de document : texte imprimé Auteurs : Mete Koken, Auteur Année de publication : 2012 Article en page(s) : pp. 736-743 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Coherent  structures  Computational  fluid  dynamics  Horseshoe  vortex  Scour  Spur  dike  Turbulent  flow 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 turbulent flow structures around an isolated spur dike located at three different approach flow angles are investigated. Detached eddy simulation is used at a channel Reynolds number of 45,000. Experimental velocity measurements were also conducted using acoustic Doppler velocimetry for validating the simulations. It is found that the size and orientation of the horseshoe vortex system change considerably with the approach flow angle. The main necklace vortex is largest in size and most coherent for 90°. Within this orientation it has larger amplitude bimodal oscillations compared to the 60° and 120° cases. A new scour mechanism is defined for the 60° case which is expected to generate more scour upstream of the spur dike. The possible scour area around the spur dike is found to be the maximum in the 90° case which is roughly by 15% larger than that of the 120° case. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.616316 [article] Coherent structures around isolated spur dikes at various approach flow angles [texte imprimé] / Mete Koken, Auteur . - 2012 . - pp. 736-743. Hydraulique Langues : Anglais (eng) in Journal of hydraulic research > Vol. 49 N° 6 (Novembre/Décembre 2011) . - pp. 736-743 Mots-clés : Coherent  structures  Computational  fluid  dynamics  Horseshoe  vortex  Scour  Spur  dike  Turbulent  flow 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 turbulent flow structures around an isolated spur dike located at three different approach flow angles are investigated. Detached eddy simulation is used at a channel Reynolds number of 45,000. Experimental velocity measurements were also conducted using acoustic Doppler velocimetry for validating the simulations. It is found that the size and orientation of the horseshoe vortex system change considerably with the approach flow angle. The main necklace vortex is largest in size and most coherent for 90°. Within this orientation it has larger amplitude bimodal oscillations compared to the 60° and 120° cases. A new scour mechanism is defined for the 60° case which is expected to generate more scour upstream of the spur dike. The possible scour area around the spur dike is found to be the maximum in the 90° case which is roughly by 15% larger than that of the 120° case. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.616316