Two-Dimensional Numerical Modeling of Flow Pattern and Bed Topography in Channel Bend

An improved two-dimensional (2D) depth-averaged model for hydrodynamic, sediment transport, and morphological adjustment is proposed in an orthogonal curvilinear grid system. A hydrodynamic sub-model considers the phase lag effect of the secondary flow by solving the transport equation of the streamwise vorticity and subsequently converts it into acceleration terms in the flow momentum equation. A sediment sub-model considers the influence of selective sorting and incorporates a simple simulation method to describe changes in the grain size distribution of the bed surface. The 2D numerical model was subsequently applied to different channel bend experiments. Comparison of the model simulation results and the measurements presented acceptable agreement, validating the capability of the 2D model for predicting the flow patterns and bed evolution in river bends.

Automated summary

An improved 2D depth-averaged model is proposed for predicting hydrodynamic, sediment transport, and morphological adjustment. By considering the phase lag effect of the secondary flow and the influence of selective sorting, the model can accurately predict the flow patterns and bed evolution in river bends.