LAUSR

In this study, the air-water two-phase flow in a strongly curved 30° open-channel bend is numerically simulated and analyzed. The research is motivated by the fact that most of the sharp or mild bend flow studies are focused on the 90, 120, and 180° bends. Although these curvatures form from the bends with lower degrees, i.e. 30° curvatures, there is no published work in this field. Due to the paucity of data in the literature, the CFD procedure here is validated using the experimental data of a sharp 90° bend of a previous study. The Reynolds-averaged Navier–Stokes equation system is used as the governing equations and the finite volume method is employed for the discretizations. The Volume of Fluid free-surface tracking method, in conjunction with the Standard k-ε turbulence model, is utilized for the air-water interactions and turbulence closure. It is found that the secondary flow intensity in the 30° bend is minor than the 90° bends. However, the tendency to flow separation is more intense in these bends, which is due to the momentum of the fluid particles passing the curvature. The results of this study may be used to control the river morphology.