Comparison and Simulation of Flow Pattern in a 90 Degree Mild Bend Using CCHE2D and SRH-2D Models

Flow in river bends is three-dimensional, the combination of secondary flow and longitudinal flow in rivers leads to the formation of helical flow which is the main cause of erosion in the outer bend and sedimentation in the inner bend. So far, many numerical models regarding flow patterns in rivers have been introduced and available to river engineering scholars. Moges et al. (2010) simulated the hydraulic and sediment flow in Meander Rivers using SRH-2D two-dimensional model and eventually determined the best equation for predicting the water surface profile and bed level changes in sediment situations. Naji Abhari et al. (2010) studied the flow pattern in a 90 degree bend. The results of their study results showed that from the beginning of the bend till the 30 degrees angle the maximum velocity is close to the inner wall and from the 30 degree angle till the end of the bend the maximum velocity is diverted to the outer bend. Maghrebi (2012) studied the turbulent flow pattern in a longitudinal range of Karoon river, containing two 180 degree steep bends using MIKE21FM and CCHE2D models, the results showed that that both models simulate the flow pattern accurately. The aim of the present study is simulation of the flow pattern in a 90 degree mild bend using CCHE2D and SRH2D models.