饱和非饱和土壤中溶质运移的数值模拟

本文结合拉格朗日观点的运动坐标与欧拉观点的固定坐标,分别求解对流—弥敌方程的对流效应和弥散效应,并在从固定坐标向运动坐标投影时利用了三次样条插值方法,使模型更为精确而简单。通过与特定情况下的理论解比较,说明模型是准确可靠的。通过与实验室室内试验结果的比较,模型的可靠性得到了进一步的验证。利用模型对淡水洗盐结合浅群井抽排咸水治理盐碱地过程的模拟分析,认为结合浅群井抽排可较大地提高淡水洗盐的效果。

THE NUMERICAL SIMULATION OF SOLUTE TRANSFER IN SATURATED AND UNSATURATED SOIL

In the present paper, numerical simulation of solute transfer in saturated and unsaturated soil is given. The convection and dispersion terms in the equations governing water and salt motion are solved respectively by using Langrangean moving coordinate and Eulerian fixed coordinate systems. Furthermore, cubic spline interpolation method is employed for the projection from the fixed coordinate to the moving coordinate, which makes the model more exact and simpler. The comparisons with theoretical solution in a specific case and experimental results of a soil column in laboratory verify the correctness and reliability of the model. Finally, this model is used for analysis of fresh water leaching. The numerical computation indicates that using shallow mass wells for pumping and draining, the effect of fresh water leaching for saline land reclamation can be greatly enhanced.