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Preference assessment of energy and momentum equations over 2D-SKM method in compound channels

Danial Hosseini, Mohammadamin Torabi, Mohammadreza Alavi Moghadam


Gradually varied flow in channels could be assessed and investigated from both the energy and momentum equations standpoints. Depending on what method is implemented, the computational results could be different. Currently, there is an ambiguity on the preference of utilizing the energy and momentum equations standpoints. This study attempts to respond to this ambiguity and the question that among these pair viewpoints which one would provide a closer solution to reality. In this respect, the Froude number, which is representative of the flow characteristics, was assessed by 1-D energy and momentum equation and 2-D Shiono and Knight Method (SKM). The obtained Froude number by 2-D SKM method considered as a benchmark to compare the energy and momentum methods. For this purpose, Froude number of ten different compound channels with different dimensions and geometries have been calculated by 2-D SKM method and compared with 1-D energy and momentum equation standpoints. The results showed that the 1-D momentum equation has more accurate results, compared to energy approach and when the height of flow in the floodplains is lower than 0.2 Hr (relative depth), the 1-D equations do not respond accurately.


Momentum and energy methods; Froude number; two-dimensional analysis; compound channel

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