徐六泾控制节点污染物运移轨迹模拟

对三维多功能动力-生态耦合模式(COHERENS)进行二次开发,运用"网格冻结法"实现了漫滩和露滩过程中的干湿交替,突破其为固定边界和限制水深的局限,使COHERENS模式成功应用于长江口浅滩过程的模拟。对潮位和水流流速的模拟结果进行了较好地验证。在斜压流场的基础上对示踪颗粒拉格朗日运移进行追踪,对污染物欧拉输运进行数值模拟。以徐六泾控制节点横断面设置颗粒示踪子和污染物排放点,对排放的悬浮颗粒物质和溶解性污染物的运动轨迹和特征进行了模拟和比较分析,给出了模拟期间的流场特征和污染物输移规律。

Numerical simulation on pollutant tracking released from the Xuliujing node transect

A coupled hydrodynamic-ecological(COH ERENS) model,with anorthogonal horizontal coordinates and a σ-vertical coordinate,was combined with a 3-D Lagrangian drifter tracking module and a water quality module to construct the hydrodynamic part of the modeling system.The COHERENS model was used to study water exchange and pollutant transport in the Changjiang Estuary.The particle tracking method,as applied in the sing lerelease experiments,provides a picture of the residual flow in the certain parts of the Changjiang Estuary.The COHERENS model had been modified by means of the changing grid technology and the dry-wet method to deal with the moving boundary.The model was calibrated and validated using tidal data available for represent ativestations.Both the magnitude and phase of the water elevation and velocity were reasonably reproduced.The numerical simulation was performed of the tidal current and pollutant diffusion from the Xuliu River node transect in the Changjiang Estuary to reveal suspended particle matter and dissolved pollutant transport in this area.By calculation of the track of Lagrange particle(or particles mass centre) and Eulerian dissolved contaminant mass centre realsed from the Xuliu River node transect,the effects of current fields on the pollutant transport and diffusion were analyzed. The current field characteristics and the pollutant transport rule were discovered.