正交曲线坐标系准三维全沙数学模型

为了定量地预测规划河道特别是规划河堰附近的河床冲淤情况,做好拦河堰与河道的规划工作,建立了一个能考虑各泥沙粒径组的级配、流线曲率与流路曲率的差异以及能同时对推移质与悬移质泥沙进行计算的正交曲线坐标系准三维全沙数学模型.用正规划重建倒伏式拦河堰的某河的现有河道实测资料对该模型进行了验证.验证结果表明,冲淤计算结果与实测结果基本一致.以该河规划重建的倒伏式拦河堰为讨论对象,取其上下游一定的规划河道区间为计算河段,对设计洪水时的冲淤情况进行了模拟预测.预测结果表明:该模型的水位计算结果与一维非均匀流模型的计算结果基本一致并更符合河道的地形特征,河道冲淤趋势符合河道及水流的特征;规划堰上下游附近的河床冲刷量最大为3.0 m,整个计算河段的冲淤量也在-3.0~3.0 m范围内.可见,规划河道具有较好的稳定性,规划堰的选址是比较合适的.

Quasi-three-dimensional mathematical model of total sediment transport in orthogonal curvilinear coordinates

In order to predict the erosion and deposition conditions of a riverbed, especially the conditions near a planned weir,a quasi-three-dimensional simulation model of total sediment transport in orthogonal curvilinear coordinates was developed.The model considered not only the sediment sorting effect but also the difference between streamline curvature and channel curvature.The model was verified by the measurement data of a river where the weir is being re-planned. The results show that the calculations basically agree with the measurements.The verified model was then used to predict the erosion and deposition under the conditions of design flood.The prediction results indicate that the calculated water levels of the proposed model are in good agreement with those of the one-dimensional non-uniform flow model and the topographical characteristics of the river channel.It is also indicated that the prediction of riverbed deformation agrees with the characteristics of the river channel and flows,the maximum erosion depth near the weir is about-3.0 m,and the erosion and deposition depths along the whole river reach are in the range of-3.0 m to 3.0 m.Therefore, the planned channel has good stability,and the selected location of the planned weir is suitable.