Numerical simulation of shallow recirculating flows in sudden enlargements

Investigations on different shapes of harbors at various flow conditions are expected to deliver numerous benefits in designing them, including keeping them clean, reducing the amount of pollutants carried by water flow and decreasing the disposing time of the contaminants. In this study, river harbor-like structures (sudden enlargements) were analyzed by 3-D numerical simulations. Analyses were carried out in an 8 m long, 1 m wide open channel with a sudden enlargement width of 0.5 m. The analyses were performed in three different geometries named as structures A, B and C. In structure A, the sudden enlargement was followed by a sudden contraction with a distance of 1 m in the flow direction. In structure B, the distance between the sudden enlargement and contraction was set to be 2 m, while in structure C there was no contraction after the sudden expansion. The depth of flow ranged from 10 mm to 100 mm. The flow of water and its recirculation in the sudden enlargements were studied by using the shear stress transport (SST) k-ω turbulence closure model. ANSYS FLUENT was employed in the computational fluid dynamic (CFD) simulations. The results of the simulations were compared with the experimental investigations in the literature.