Numerical Simulation of 3D Flow Pattern at Lateral Intake in 180-degree bend

In this research, a three-dimensional numerical model has been developed to simulate the flow pattern at lateral intake in 180-degree bend. Due to the curvature of flow boundaries and computational grid, the three-dimensional Navier-Stokes equations are solved in nonorthogonal and nonstaggered curvilinear coordinates, and given the complexity of the flow conditions, the k-ω model for low Reynolds numbers is used to solve turbulence terms. The equations are discretised by the finite volume method and the central difference and power law algorithm are used to discretise the diffusion and convection terms, and the stable semi-implicit (SIMPLEC) is used to couple the flow and pressure field. Also, to increase the efficiency of the model, one block with variable domain has been used to simulate both channels (main and intake). The developed model was first validated in two tests of flow in 180-degree bend and the lateral intake in a straight flume. Then flow pattern at the lateral intake in 180-degree bend for 45-degree diversion angle in the establishment angle of 40-degree was simulated and compared with the available laboratory data. The average modeling error in the main channel and intake was about 7.3% and 19.7%, respectively, which is acceptable compared to the results of other commercial models.