多孔介质中非均匀流动模式示踪试验与弥散限制聚合分形模拟的应用

通过田间试验研究探讨了土壤水非均匀流动特性及其描述方法。采用染色示踪剂观察了土壤水非均匀流动模式，并采用功率谱分析方法探讨了流动的尺度特性。应用弥 散聚合限制模型(DLA)模拟非均匀流动模式。研究结果表明常耕地和废弃地条件下的非均匀流动的流动模式、染色比例、含水率变化量以及溶液浓度随深度的变化规律明显不同。功率谱分析表明，非均匀流动具有尺度相似性。弥散聚合限制模型中，粒子通过随机移动生成分形结构体，通过改变移动概率和进行结构分层使模型产生的流动形状与实际流动模式一致，说明DLA模型能较好的模拟非均匀流动，同时表明土壤非均匀流动具有分形特征。

Experimental study on heterogeneous flow in porous media by tracing technology and application of diffusion limited aggregation fractal modeling

The field tests are carried out to study the characteristics of heterogeneous soil water flow in tilled land and fallow field respectively.The Tracing technology is applied to observe the movement of flow and power spectrum analysis method is used to investigate the spatial variability and scale-dependency of the flow.The study result shows that the distribution of dye coverage,electric conductivity and soil water content are obviously different in two experimental plots.The power spectrum analysis shows that the heterogeneous flow exhibits a scale similarity characteristic.The moving path of dye solution is simulated using diffusion-limited aggregation(DLA) model.By modifying the random moving probability and introducing various probabilities to different layers the model successfully simulates the flow in soil and the calculation result well agrees with experimental data.Furthermore,the field observation data also shows the heterogeneous flow exhibits the behavior of fractal.