Abstract

A 3-D flow and sediment model in curvilinear collocated grid has been developed from 2-D model. In the horizontal x-y-plane, a boundary-fitted curvilinear co-ordinate system is adopted, while in the vertical direction, a σ co-ordinate transformation is used to represent free surface and bed topography. The total pressure is subdivided into the hydrostatic and residual hydrodynamic components. K-ε turbulent flows model, non-staggered curvilinear grids, momentum interpolation, SIMPLEC and SIMPLER algorithms were used to solve the basic equations. Non-equilibrium sediment transport is applied in the model. The treatments of bed shear stress and the equilibrium concentration were presented.

In order to verified and tested the numerical model, “S” type open channel flow was simulated with the model, the suspended load model was tested for open channel flow situation with net entrainment from loose bed and with net deposition. The results for the numerical model were tested against available data. Good agreement and accuracy were obtained. The mathematical model was applied to serve the engineering projects. The different levels discharge flow in Nanjing river reach were calculated, bed scour and sedimentation in engineering river reach during one hydrologic year was verified . All results were agreement with measurements.

Keywords: 3-D flow and sediment mathematical model, non-orthogonal curvilinear collocated grids, momentum interpolation, non-equilibrium sediment transport