Investigation of the Geometric and Hydraulic Parameters' Effects on the Separation Zone Dimensions in Lateral Intakes Using Fluent Software

Abstract

In this study in order to understand the flow pattern in river lateral intakes, numerical simulation of the flow in a rectangular open channel using FLUENT software has been carried out. The velocity field at different sections near the surface of water was obtained using different turbulent models such as Standard k-e, k-w and RSM which then were compared with experimental datum. It was found that abandoning the isotropic eddy-viscosity hypothesis, the RSM accounts for the effects of streamline curvature and swirl in a more rigorous manner than other models. In a parametric study for an intake with different width ratios in a 900 junction and also for an intake with different angles of deflection, the effects of important variables such as Froude number and discharge ratio on the dimensions of separation zone using RSM model were investigated. This paper introduces different relations between dimensions of separated zone in the intake and mentioned variables. It was found that the size and location of the separation zone is very much dependent on the discharge ratio. In all cases, the results showed that an increase in the discharge ratio causes shortening and narrowing of the separation zone. For a constant discharge ratio, by increasing the channel width ratio or angle of deflection, separation zone occurs closer to the entrance.