Paper Info
Title
Entropy Wake Law for Streamwise Velocity Profiles in Smooth Rectangular Open Channels.
Abstract
In narrow open channels, the three-dimensional nature of the flow and the transport momentum from the sidewalls to the central region cause the maximum longitudinal velocity to occur below the water surface. The entropy model is unable to accurately describe the velocities near the free surface when the dip phenomenon exists. The present paper proposes a new dip-modified entropy law for steady open channel flows, which consists of three additional terms: the first one similar to Coles' function; the second one linearly proportional to the logarithmic distance from the free surface; and the third one depending on the cubic correction near the maximum velocity. The validity of the new model was tested on a set of laboratory measurements carried out in a straight rectangular flume with smooth boundaries and for different values of water discharge, bottom slope, and aspect ratio. A detailed error analysis showed good agreement with the data measured through the present research and a more accurate prediction of the velocity-dip-position compared with the one evaluated through the original entropy model. In addition, the modified entropy wake law matched very well with other literature data collected in rectangular cross-sections with different flow conditions.
Year
DOI
Venue
2020
10.3390/e22060654
ENTROPY
Keywords
DocType
Volume
Shannon's information entropy,wake law,streamwise velocity profiles,velocity-dip-position,open channel flows,laboratory experiences,error analysis,rectangular cross-section
Journal
22
Issue
ISSN
Citations 
6
1099-4300
0
PageRank 
References 
Authors
0.34
0
2
Name
Order
Citations
PageRank
Domenica Mirauda101.35
Maria Grazia Russo252.98