黄河下游非恒定输沙数学模型——Ⅰ模型方程与数值方法

A mathematical model for unsteady sediment transport in the lower Yellow River,Ⅰ,model equations and numerical method

构建起具有通用性的黄河下游一维非恒定输沙数学模型。该模型建立了新的泥沙连续性方程与河床变形方程 ,克服了以往数学模型计算中取饱和恢复系数小于 1等缺陷 ,引入了符合黄河下游河道水沙特点的水流挟沙力和河床糙率计算等公式 ,给出了悬移质含沙量以及悬移质泥沙平均粒径沿横向分布的计算方法 ,以及阐明了河槽在冲淤过程中河宽变化规律的模拟技术。运用Preissmann四点差分格式离散水流方程 ,并与泥沙连续性方程进行非耦合求解。

A one dimensional mathematical model for unsteady sediment transport in the lower Yellow River is developed In the model, the formulas of sediment carrying capacity and Manning roughness coefficient, which can reflect the features of two phase flows in the Yellow River, are adopted A saturation recovery coefficient is defined to represent the ratio between the bottom and the average concentration under the balance conditions, which is not a constant in this model and is evaluated by using an empirical expression obtained by integrating the sediment concentration along water depth The concentration distributions and the mean diameter distributions of suspended sediment in the transversal direction are also estimated in this model The Preissmann four point infinite difference scheme and algorithm for Tridiagonal Matrix Eqs. are employed in the numerical method