An ordinary differential equation for velocity distribution and dip-phenomenon in open channel flows / Absi, Rafik in Journal of hydraulic research, Vol. 49 N° 1 (Janvier/Fevrier 2011)  

An ordinary differential equation for velocity distribution and dip-phenomenon in open channel flows [texte imprimé] / Absi, Rafik, Auteur . - 2011 . - pp. 82-89.
Hydraulique
Langues : Anglais (eng)
in Journal of hydraulic research > Vol. 49 N° 1 (Janvier/Fevrier 2011) . - pp. 82-89

Mots-clés :	Dip-phenomenon Eddy viscosity Log-wake law Open channel flows Ordinary differential equation Semi-analytical solution Velocity distribution
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 :	An ordinary differential equation (ODE) for velocity distribution in open channel flows is presented based on an analysis of the Reynolds-averaged Navier-Stokes equations and a log-wake modified eddy viscosity distribution. This proposed equation allows to predict the velocity-dip-phenomenon, i.e. the maximum velocity below the free surface. Two different degrees of approximations are presented, a semi-analytical solution of the proposed ODE, i.e. the full dip-modified-log-wake law (fDMLW-law) and a simple dip-modified-log-wake law (sDMLW-law). Velocity profiles of the two laws and the numerical solution of the ODE are compared with experimental data. This study shows that the dip correction is not efficient for a small Coles' parameter, accurate predictions require larger values. The sDMLW-law shows reasonable agreement and seems to be an interesting tool of intermediate accuracy. The fDMLW-law, with a parameter for dip-correction obtained from an estimation of dip positions, provides accurate velocity profiles.
DEWEY :	627
ISSN :	0022-1686
En ligne :	http://www.informaworld.com/smpp/content~db=all~content=a933344782~frm=titlelink