2D numerical modeling of grain-sorting processes and grain size distributions

• We develop a two-dimensional hydrodynamic-morphological and sediment transport model.
• We considers grain sorting effects in the non-uniform sediment transport model.
• A simple method is adopted herein to update the grain size distribution.
• A well-known downstream fining experiment was used to test the 2D numerical model.
• The model simulation results and the measurements are in acceptable agreement.

A depth-averaged finite difference two-dimensional hydrodynamic-morphological and sediment transport model is presented in the orthogonal curvilinear grid system. The sediment submodel considers the influence of selective sorting by modifying the sediment transport capacity and incorporates a simple simulation method to describe changes in the grain size distribution of the bed surface by solving the governing equation for sediment mass conservation. The 2D numerical model was applied to the experiment on downstream fining. The model simulation results and the measurements are in acceptable agreement. The result illustrates the capability of the two-dimensional model to predict the sediment wedge evolution and grain sorting process.