3D SIMULATION OF FLOW AND POLLUTANT TRANSPORT IN THE SOUTH BRANCH OF THE CHANGJIANG ESTUARY

摘要

The Changjiang Estuary nearby Shanghai is one of the largest and the most complicated estuaries in China. The flow exhibits obvious 3D structure in the Changjiang Estuary due to the complex topography, tide and runoff, and the pollutant transportation is also complicated in the region. The south branch of the Changjiang Estuary is the main outfall channel to the East China Sea, and the runoff of south branch is about 95 percent of total runoff of the Changjiang Estuary. Based on POM Model, the three-dimensional flow and mass transportation mathematical model with an orthogonal curvilinear coordinate in the horizontal direction and sigma coordinate in the vertical direction for the south branch of the Changjiang Estuary is established in this paper. The basic equations are discretized by the finite difference method and the process splitting skill (the numerical computational process is divided to external mode and internal mode) is applied in this model. The computed range in south branch of the Changjiang Estuary is 91.70 kilometer in length and 1328.81 km~2 in area. The three dimensional flow field and polluted scope by Shidongkou waste discharge outlet of Shanghai city are simulated, and the computational results mimic the observed data well. This work is benefited for guidance of waste pollution control in the Changjiang Estuary.