珠江三角洲河网悬沙数学模型分析

Numerical Model Analysis on Suspended Sediment of River Networks in Pearl River Delta

物理模型对于复杂多变的河网河道的水力因素变化不易描述,数学模型已成为研究其河道水力、泥沙问题的重要手段。在线性化的Pressmann四点隐式差分法基础上,应用汊点分组思想求解河网流场,采用节点悬沙控制方法对珠江三角洲河网悬沙进行了数值模拟,利用实测资料对模型进行率定与验证,并分析了珠江三角洲流域河网悬沙输移特征。结果表明,数值模拟结果真实、可靠,与实测资料基本吻合,从而再次证明珠江三角洲河网是以径流输沙为主的平原河网。建立悬沙节点控制方法进行河网悬沙的数值模拟,实现了泥沙方程组的分级解法,提高了计算效率与精度。

A numerical model for simulating the unsteady flow and suspended-sediment transport of river networks is presented here.Based on the Pressmann Quatre Implicit Difference Scheme,the junction group method is applied to solve the flow matrix equations,and the numerical modeling of the whole Pearl River Delta is carried out by using the node control method for sediment concentration. The parameters of the model are calibrated according to the recorded data,the result is satisfactory.Also,the characters of transportation of the suspended sediment are analysed through the rates of flow and sendiment in the junction river.At last,it is showed that the Pearl River Delta is a plain river basin transporting sendiment based on flow.