部分水深平均二维计算模型的研究

通过研究天然河流中瞬时源排放近区垂向混合规律，建立了部分水深平均二维计算模型，推导得出瞬时点源垂向均匀混合的纵向距离及垂向部分混合水深的理论表达式，并建立线源排放垂向均匀混合的给 距离及垂向部分混合水深的函数关系，把上述成果引入了部分水深平均二维计算模型，将其应用于长江口段罗丹明示踪剂瞬时源排放浓度场的计算中，计算结果与现场趾监测资料及全场水深平均二维模型的计算值进行比较，可看出部分水深平均模型计算值与实测值证较好，而全水深平均模型的计算值在近排口范围内与实测值相关较大。

A 2D Numerical Model for Part Depth Homogeneous Mixing

The part depth homogeneous mixing 2D numerical model has been studied on the basis of vertical mixing law of the instantaneous source in natural flow. By theoretical analysis,two equations for the distance of vertical homogeneous mixing and the part depth of homogeneous mixing for the instantaneous point source are presented. Then the relationship between the two varieties for instantaneous linear source is obtained. On the basis of the law,a part depth homogeneous mixing 2D numerical model is developed,which has been used in concentration field calculation. By use of the measured data of Rhodamine-B tracer in the Yangtze river estuary,the comparison of calculated value with measured data is made. The value calculated by the new model approximates to the measured data,and the value calculated by the whole depth mixing 2D model is much smaller than the measured data in the near field. The new model is superior to the conventional 2D model.