Three-dimensional numerical simulation of flow pattern at intakes from straight channel with a trapezoidal section

In this study, a numerical 3D model for simulation of lateral intake from the main channel with trapezoidal section has been developed. This model has solved the 3D Reynolds equations using finite volume method and k-ω turbulent model for solution of turbulent equations. The equations discretized at non-orthogonal and non-staggered curvilinear mesh. Given the lack of mesh orthogonally, it is necessary to enter a new item for modification of pressure equations. Also, power-law scheme and the SIMPLE algorithm have been used for parameter’s discretization and pressure-velocity coupling respectively. Developed model verified by simulating of complex flow pattern at lateral intake from a straight channel and a proper fitness between laboratory data and the model results was obtained. After that, the effect of side slope of the main channel wall on the flow pattern and division zone width was examined and showed by increasing slope from the vertical mode, the ratio of intake flow from the surface is more than the bed and this can be effective in reducing sediment entry to the intake. In this situation and in contrast to the intake from channel with vertical wall, the variation of division’s width, from the floor to the surface of the water is initially decreased and then increased.