连云港近岸海域污染物输移规律

Transport laws for pollutants in coastal area of Lianyungang City

为研究连云港近岸海域污染物随潮流运动的输移和浓度增量的变化规律,以连云港徐圩新区新设污水处理厂远期入海排污口尾水排放为研究案例,采用非稳态浅水方程和垂向平均的二维对流扩散方程建立连云港近岸海域水动力及水质耦合模型,应用有限体积法在无结构三角形网格上对方程离散求解,模型开边界所需大、小潮潮位过程由TPXO海潮模型生成.计算结果表明:二维数值模型可较好地模拟不同水文条件下计算区域内的水动力流场和污染物的输移轨迹;其浓度增量与排放量成正比,与水体流速、水量成反比,小潮落憩时刻污染物浓度增量相对最大.

To study the variation laws of transport and concentration increment of pollutants in the coastal area of Lianyungang City under tidal motion,the sewage discharge of two newly-built sewage treatment plants in Xuwei Development Area of Lianyungang City was taken as a study case.A coupled hydrodynamic and water quality numerical model was established based on the unsteady shallow water equations and the vertically averaged 2-D convection-diffusion equations.The finite volume method was employed to discretize and solve the model on unstructured triangular mesh.The tidal levels of neap tides and spring tides on the open boundaries were generated by means of the TPXO tide model.The results indicate that the proposed model can be employed to satisfactorily simulate the hydrodynamic flow fields and the transport loci of pollutants in the coastal area of Lianyungang City under different hydrologic conditions.The concentration increment is proportional to the sewage discharge and inversely proportional to both the flow velocity and the water quantity,and the concentration increment of pollutants at slack of neap tides is relatively the largest.