Experimental Measurement of Macropore Flow in Porous Media

这项研究将测量和量化土壤大孔隙中流动的水力学以及大孔隙与周围多孔介质之间的相互作用。将使用非破坏性伽马射线层析成像装置获得实验室柱子中的水含量分布，分辨率在流动事件期间为5毫米，在重新分配后为2毫米。将测试各种不同的孔隙类型，它们的大小和形成方法将不同。这些对时间和空间变化的土壤水分的直接测量将允许计算水流水力学。这些结果将反过来与现有的大孔隙流确定性理论进行比较。将评估的具体假设包括：1)大孔隙内的泊松流动，2)孔隙与周围多孔介质之间的水力平衡，3)将孔隙中的水的径向吸附模拟为正常的水平吸附的适用性，以及4)表面密封对水进入孔隙的影响。

This research will measure and quantify the hydraulics of flow in soil macropores and the interactions between macropores and the surrounding porous media. A non-destructive gamma ray tomography unit will be used to obtain water content distributions in laboratory columns to a resolution of 5 mm during flow events and 2 mm after redistribution. A variety of pore types will be tested which will differ in size and method of formation. These direct measurements of the temporal and spatially varying soil water content will allow the calculation of flow hydraulics. Those results will in turn, be compared to existing deterministic theories of macropore flow. Specific assumptions which will be evaluated are; 1) poiseuille flow within the macropore, 2) hydraulic equilibrium between the pore and the surrounding porous media, 3) the suitability of modeling the radial sorption of water from the pore as normal horizontal sorption, and 4) the effects of surface seals on the entrance of water into the pore.