多孔介质中非均匀流动模式信息特性聚类分析

Characterizing heterogeneous flow patterns in porous media using cluster analysis

研究了多孔介质中非均匀流动描述方法和流动模式信息特性。依据流道宽度分布信息,对4组染色示踪试验的垂直剖面流动区域进行水平分层,将流道统计信息作为变量,对水平层进行系统聚类分析。结果表明,染色比例和染色区域内流动通道宽度分布是流动聚类分区的主要影响因素。聚类数目为3和8情况下,能够最为有效地表征非均匀流动模式。以垂直方向流动为主,且流动通道连续的情况下,流动分区主要包括全局性均匀流、局部均匀流、均匀流向非均匀流过渡区,以及优先流区。水平方向流动特性较为显著的情况下,则存在多个均匀流向非均匀流动的过渡区。

The objectives of this study are to develop a quantitative method to describe heterogeneous flow patterns and identify the heterogeneous information characteristics based on flow patterns. Dye tracer experiments were performed on plots with different conditions. The flow patterns were separated into similarly stained horizontal layers based on the width distributions of the stained areas. Then the layers identified in the flow patterns were partitioned into groups with similar patterns by hierarchical clustering. The results show that the dye coverage and width of stained structures are the most indicative factors for the dif- ferent clusters. The number of clusters affects the degree of layer discrimination. Three and eight clusters seem to be sufficient to capture the main characteristics of the heterogeneous flow patterns. For the experimental plots where the vertical flow is dominated, the clusters contain the layers with the homogeneous flow, preferential flow, and those with flow changes from homogeneous infiltration to preferential flow. For the experimental plots where the horizontal heterogeneous is significant, the soil horizons has a strong influence on the water flow patterns.