Author(s): Z. Liu; Y. Chen; Z. Wang
Keywords: No Keywords
Abstract: The simulation of mixing zone discharged from natural riverside has the difficulties such as three-dimensional distribution, meshes refinement, inefficiency, etc. A three dimensional numerical model for the pollutant mixing zone from the natural riverside outfall is developed using sigma-coordinate for the vertical dimension. The finite element approach in the horizontal plane combining with a layer-integrated scheme alone the vertical dimension is applied for easy adaptation to complex boundary configuration. The hierarchy grids and the local time-step scheme are employed to overcome the difficulty of predicting the small-sized side discharge into a huge scope of received water body. A case study for the side discharge into a straight open-channel flow shows that numerical results are verified well by experimental data. Furthermore, the present model is also verified by the field surveying data of both the velocity and the concentration near a side discharge outfall in Fuling Reach of Three Gorges Reservoir before the reservoir formed. It is shown that the good predicting solution can be obtained due to dealing well with the variation of water free surface along the river, the complex riverside, side discharge outlet and underwater topography in the present model.