Numerical Analysis of the Mixing Zone for a Vertical Discharge into a Tidal River

This paper analyzes the mixing zone of a vertical discharge of sewage into a natural tidal river with strong tidal currents. The paper presents a numerical model, which combines 1 D and 2 D models to compute the mixing zone for the Sibao Segment of the Qiantang River. The simple 1 D model was used to model the flow for the entire river using field data as the boundary conditions. The complete depth averaged turbulence model was used for the 2 D computation. The calculated results agree well with the field observations. The analysis provides a practical method for the computation of mixing zones in tidal rivers.