Hydraulic contacts controlling water flow across porous grains.
Hydraulic contacts controlling water flow across porous grains.
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液压触点控制流经多孔颗粒的水流。
DOI：
10.1103/physreve.76.026311
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
M. Stampanoni
中科院分区：
文献类型：
--
作者：
Andrea Carminati;A. Kaestner;Hannes Flühler;P. Lehmann;Dani Or;Eberhard Lehmann;M. Stampanoni
多孔颗粒之间的水流变化很大，这取决于颗粒之间接触处的水分布。触点的水力行为从水填充触点时的高导电性变化到随着水压下降和触点粗糙体快速排出而流动的瓶颈。这种变化极大地影响了多孔颗粒包（如团聚土）的导水率。水流过触点的主要驱动力是毛细作用，通常使用毛细数和邦德数相对于重力和粘性力进行量化。对于快速的水渗透，粘性力占主导地位。为了简单起见，我们模拟了球形多孔颗粒之间的水分布，这些颗粒的表面被半径小得多的球形凸起覆盖。我们提供的实验证据，通过中子射线照相术和基于同步辐射的X射线断层扫描显微镜记录跨接触的流动行为的转变。
Water flow between porous grains varies widely depending on the water distribution in contacts between grains. The hydraulic behavior of contacts varies from highly conductive when water fills the contacts to a bottleneck to flow as water pressure drops and contact asperities rapidly drain. Such changes greatly impact the hydraulic conductivity of porous grain packs such as aggregated soil. The dominant driving force of water flow across contacts is capillarity, often quantified relative to gravity and viscous forces using the capillary and Bond numbers. For fast water infiltration, viscous forces dominate. For simplicity we modeled the water distribution between spherical porous grains whose surfaces are covered by spherical bumps of much smaller radii. We provide experimental evidence obtained by neutron radiography and synchrotron-based x-ray tomographic microscopy documenting transitions in the flow behavior across contacts.