Evaluation of FLOW-3D Numerical Model in Predicting the Morphological Changes at River Junction

Due to hydraulic complexity in confluences, the study of different features of these locations such as sedimentation, erosion, and environmental considerations are of high interests to many researchers. Although many laboratory researches have been carried out regarding erosion and sedimentation in confluences, little researches have been done numerically. In this research the features and performance of FLOW-3D numerical model to simulate the flow, erosion, and sediment transport patterns in a junction of 2 canals with different flow rates and constant sediment flow, are investigated by comparing the results obtained from the numerical model with those obtained from a laboratory model. The widths of the canals of the physical model were 15 and 50 centimeters. The comparison between numerical and physical models shows an average of 6.3% error between maximum sediment depth in the junction of lateral and main canal between two models. Moreover, according to the measured results of erosion depth at the right bank of the main canal at the junction, the numerical model can estimate the erosion at the bank with the average of 26% error. Furthermore, the numerical model was able to predict the water surface profile of the flow in the junction with an average error of 1% when sediment was not injected.