Entropic model application to identify cross-sectional flow effect on velocity distribution in a large amplitude meandering channel

Abstract

Literature shows the application of the entropy concept in open channels flow. No existing research has been addressed to the application of the entropy concept for evaluating the effect of secondary flow which especially develops in curved channels. The purpose of this paper is to explore the possibility to evaluate the effect of the secondary flow on the stream-wise velocity distribution starting only from the knowledge of the surface velocity and the entropic concept application. The analysis is conducted with the aid of data collected in a large-amplitude meandering laboratory flume for two different values of the width-to-depth ratio. Results show that the location of the maximum velocity varies not only along the bend but also along the water depth, depending on the relative entity of the cross-circulation and the convective flow acceleration. It has been also verified that the entropic parameter varies along the bend as a function of the width-to-depth ratio. The application of the entropic model to the examined cases has allowed the verification that not only the shape of the velocity profile but also the bed shear stress evolution along the bend could be estimated by the entropic model starting from the knowledge of the surface velocity only.