基于随机水流网络的土壤水非均匀运动数值模拟

Numerical simulation of water transport in soil based on the water flow networks

用显色示踪方法通过试验研究了黏土的非均匀流动模式,建立了离散网络模型,根据土体的统计特征描述相互作用的大孔隙和流动通道,构建水流运动的网络系统与小孔隙连续介质的耦合模型。用控制体积有限元法求解两区土壤水分运动的基本方程,采用整体法将土壤基质水流运动方程和不规则水流网络区水流运动方程耦合,解决了网络通道交叉引起的水流相互影响的问题,提高了计算效率。模拟与实验结果对比表明,离散网格模型及方法较好地描述出了优先流运动的特点,比等效连续体模型更为有效的刻画了土壤水流非均性规律。

Based on the iodine-starch staining experiments,a series of discrete networks model are developed and the transport of preferential flow is simulated.According to statistical characteristics of flow channels,the equations of water flow in soil matrix and in irregular network are coupled by adopting integral method,which solves the problems of the flow mutual influence caused by the cross-channel network,and improves the computational efficiency.The comparison of simulated and experimental results indicates that the usage of the model provides a better way to characterize the preferential flow,and discrete network model has a better description of soil-water heterogeneous discipline than that of equivalent continuous model.