Numerical Simulation Of Hydrodynamic Flows In The Qingcaosha Reservoir

The project of the Qingcaosha reservoir is one of the significant infrastructure construction projects that have been included in"The Guideline of Shanghai the 11th Five-Year Plan of Economy and Society Development". It greatly contributes to"one-hundred-year strategy"of the development of Shanghai water source system, in which the quantity, the quality and the safety of Shanghai raw water supply are of concern. After completion of the reservoir project,the flows are induced by wind and water discharge under the effect of lateral boundaries and the associated solute transport appears. It is an important issue to study on the flow pattern and water quality in the reservoir.The numerical model of hydrodynamic flows in the reservoir and in the Yangtze estuary is established with the commercial code Delft-3D. An analytic solution of the wind driven current was sued to validate the numerical model for computation of the wind driven current. The measured data, in terms of the tidal elevation and velocity, was used to validate the three dimensional numerical model of tidal flows in the Yangtze estuary.Considering a simple case of flows in a rectangular basin, the numerical model was implemented for three different formulations of the lateral walls, i.e., the free-slip wall condition, the no-slip wall condition and the partial-slip wall condition. Comparing with the flow patterns obtained by a model test, it turns out that the no-slip wall condition works well for numerical simulation of the small-scale flow in a laboratory model. However, the numerical simulation of the flow with the free-slip wall condition could show the same flow pattern as the experiment.The numerical model is used to study the hydrodynamic flows in the Qingcaosha reservoir of the full scale. The computed results show that there is little effect of the different lateral wall conditions on the overall hydrodynamic flow patterns, except some kind difference of local flows near the lateral walls.Through numerical simulation of hydrodynamic flows, the wind driven current was studied for the cases of two typical wind conditions. The patterns for fluid flows induced by wind and water discharge of the reservoir were obtained, which show several characteristics of the flows. The material transport in the water was investigated numerically and the water exchange rate in the revervoir was proposed and discussed.