Author(s): Farhad Bahmanpouri; Silvia Barbetta; Tommaso Moramarco

Linked Author(s): Farhad Bahmanpouri

Keywords: Entropy concept; Remote Sensing; UAV-method; Secondary currents; Reynolds shear stress

Abstract: The majority of freshwater on earth is transported by rivers and streams. Many cities are located near large rivers and streams, where water plays an important role. Hydraulic parameters in a stream or river can be considered and inferred in numerous ways, but velocity and discharge rates are particularly important. The Entropy concept has been increasingly applied by researchers for estimating the velocity and discharge in rivers, especially for high flow conditions. The current research aims to repost a review on the application of the Entropy concept in rivers with different geometric and hydraulic characteristics. Entropy-based investigations shed light on how the 2D structure of velocity distribution for large river flows can be identified just by monitoring nearsurface velocities. The estimated flow velocity pattern well reflects the one gathered by ADCP across large and narrow transects during both low and relatively high flow conditions. Some examples can be inferred, respectively, from measurements analysis at Sajo and the Freiberger Mulde Rivers in Germany and the Negro and Solimoes rivers in Amazon. Results highlighted that the Entropy approach can accurately predict the velocity distribution and discharge rates just relying on the surface velocity with a percentage error lower than 15%. Recently, the Entropy approach has been applied to calculate the Reynolds shear stress through Italian Rivers. The velocity dip induced by secondary currents for accelerating flow was associated with the distribution of Reynolds shear stress at selected verticals. Overall, the findings of the current research highlighted the benefits of Entropy application for evaluating the characteristics of flow in natural rivers.

DOI: https://doi.org/10.3850/978-90-833476-1-5_iahr40wc-p1189-cd

Year: 2023