Scaling of water flow through porous media and soils
Scaling of water flow through porous media and soils
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DOI：
10.1111/j.1365-2389.2007.00986.x
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发表时间：
2007-12
影响因子：
4.2
通讯作者：
Kurt Roth
中科院分区：
文献类型：
--
作者：
Kurt Roth
概括了流体流动的标度，并与多孔介质中水流动的标度进行了对比。然后，它被应用到推导达西定律，从而表明，在代表性的基本体积（REV）的规模的流场的平稳性是一个关键的先决条件。重点是平稳性的要求，或局部平衡的影响，特别是对有效性的理查兹方程的描述水运动通过土壤。未能满足这一基本要求可能会发生在规模的REV或，特别是在数值模拟中，在规模的模型离散化。后者可以通过分配更多计算资源和采用更细粒度的表示来缓解。与此相反，前者是根本性的，并导致一个不可挽回的失败的理查兹方程所观察到的渗透不稳定性，导致指状流。
Scaling of fluid flow in general is outlined and contrasted to the scaling of water flow in porous media. It is then applied to deduce Darcy’s law, thereby demonstrating that stationarity of the flow field at the scale of the representative elementary volume (REV) is a critical prerequisite. The focus is on the implications of the requirement of stationarity, or local equilibrium, in particular on the validity of the Richards equation for the description of water movement through soils. Failure to satisfy this essential requirement may occur at the scale of the REV or, particularly in numerical simulations, at the scale of the model discretization. The latter can be alleviated by allocation of more computational resources and by working on a finer‐grained representation. In contrast, the former is fundamental and leads to an irrevocable failure of the Richards equation as is observed with infiltration instabilities that lead to fingered flow.