Numerical simulations of 3-D flows in the reach of the Xiaolangdi project

A 3-D silt-laden mathematical model based on stochastic turbulence theory was developed to analyze the flows in the river reach of the Xiaolangdi project. The scheme calculates the Reynolds stresses for anisotropic turbulent flows and solves a pressure Poisson equation for the free surface flow with a refined wall function for the solid boundaries. The sediment carrying capacity near the bed surface was estimated with the traditional equations for sorting of the bed material extended to 3-D geometries. In body-fitted coordinates, simulations of silt concentrations and velocity distributions at various cross-sections in the reach, agree well with data from physical models, which indicate this model, and this computational method and program are reliable.