3D Numerical Analysis of Bed Topography in 180 Degree Channel Bend

The complex three-dimensional flow characteristics in river bends necessitates the use of a three-dimensional numerical model. The numerical model used in this paper is called SSIIM (Sediment Simulation In Intakes with Multiblock option).The 3D model already has showed satisfactory results in related applications. In this study, SSIIM is applied to study the variation of channel bed under steady flows in a 180 mild curved open-channel with sandy bed. Bed roughness was calibrated to ks  4.5 d90  6.25d50. Comparison of results showed good agreement between the computed and measured bed topography. The model simulated both the point bars near the inner bank and the scour holes near the outer bank. In addition, the positions of these phenomena are in fair agreement with the measured data. Numerical results show some dependencies on the grid size. In addition, deviations of model from the experimental data as well as uncertainties in numerical modeling are discussed.