This paper presents a classification using a decision tree algorithm of hydraulic jump over rough beds based on the approach Froude number, F_r1. Specifically, 581 datasets, from literature, were analyzed. Of these, 280 datasets were for natural rough beds and 301 were for artificial rough beds. The said dataset was divided into four classes based on the energy losses. To compare the performance of the decision tree classifier (J48), a multi-layer neural network (NN) was used. The results suggest an improved performance in terms of classification accuracy by the J48 algorithm in comparison to the NN classifier. Furthermore, the classifier model had only four leaves and achieved an accuracy of 91.56%. Furthermore, classification results showed that the first class (A) of hydraulic jump over the rough beds is approximately similar to that for the smooth bed. Moreover, in the next three classes (B, C, and D), upper values of F_r1 decreased with respect to the smooth bed classes. Lastly, in class D, the upper value of F_r1 reduced to 7.45, which indicates that the shear stress (i.e., the energy loss) grows sharply with increasing F_r1. Put simply, bed roughness effectively increases the energy dissipation with an increase in the F_r1.

In this research, the effect of different sinuosity (s) and width of floodplain on the flow structures in curved compound channels was investigated numerically. Six different sinuosities of main channel (s = 1, 1.026, 1.096, 1.209, 1.381, and 1.641) and three different relative depths (Dr = 0.26, 0.35, and 0.45) have been used. The findings revealed that with the increase in sinuosity from 1 to 1.641 (64% increase), the maximum flow velocity in the apex section (CS1) and the middle crossover section (CS4) decreases by 23% and 62%, respectively. In the relative depth (Dr) of 0.26, 0.35, and 0.45 with the increase in sinuosity from 1 to 1.641 (with the corresponding decrease in width of floodplain), the ratio of main channel discharge to total discharge (Qmc/Q) is reduced by 40%, 45%, and 45%, respectively. Also, with the increase in relative depth (Dr), the main channel discharge is reduced, and the majority of the flows discharge through floodplain, so that with the increase in the relative depth from 0.26 to 0.45, the amount of Qmc/Q in the channel with maximum sinuosity (s = 1.641) and straight channel (s = 1) decreases by 30% and 14%, respectively. With the increase in sinuosity, the changes of v/u and the angle of flow deviation are more noticeable in the middle sections and above the bankfull level, so that in the most critical state, with an increase in the sinuosity from 1 to 1.641, the relative intensity of secondary flow (v/u) increases from 0 to 3.6, and along a meander, the size of the secondary flow cell in each section becomes larger with increasing sinuosity.