The foam drainage equation for unsaturated flow in porous media
The foam drainage equation for unsaturated flow in porous media
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多孔介质中非饱和流动的泡沫排水方程
DOI：
10.1002/wrcr.20525
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发表时间：
2013
影响因子：
5.4
通讯作者：
S. Assouline
中科院分区：
文献类型：
--
作者：
S. Assouline
非饱和多孔介质中的一类毛细流动具有准稳定粘滞流动的特征，这种流动被限制在弯曲的气-水界面后，并在毛细力沿裂缝和颗粒接触保持的液体体内。孔空间内连接的毛细管液体网络的几何形状类似于泡沫中相邻气泡（高原边界）之间形成的通道，固体颗粒代表泡沫中的气泡。对于简化的通道几何，我们将粘性流动表达式与连续性考虑结合起来，以描述重力排水过程中通道横截面积的演变。该公式使非饱和流的建模不需要调用理查兹方程和相关的水力函数。我们将最初为泡沫“自由排水”（重力下排水）或“强制排水”（渗透锋面运动）开发的一种形式应用于多孔介质中的一类非饱和流动，这些流动只需要几个输入参数（平均通道角、空气进入值和孔隙度）来满足某些初始和边界条件。我们证明，毛细管通道横截面的减小产生了自调节内部通量的一致描述，从而达到土壤中所谓的“现场容量”，并为在规定压力边界条件下解释流出实验提供了另一种方法。此外，几何上显式的公式提供了更直观的毛细流动穿过纹理边界（通道横截面和通道数量的变化）的图像。泡沫排水方法扩大了非饱和流动过程分析工具的范围，并提供了非饱和多孔介质中液体形态和流动动力学之间更现实的联系。
A class of capillary flows in unsaturated porous media is characterized by quasi steady viscous flow confined behind curved air‐water interfaces and within liquid bodies held by capillary forces along crevices and grain contacts. The geometry of the connected capillary liquid network within the pore space resembles channels that form between adjacent bubbles in foam (Plateau borders) with solid grains representing gas bubbles in foam. For simplified channel geometry, we combine expressions for viscous flow with continuity considerations to describe the evolution of the channels cross‐sectional area during gravity drainage. This formulation enables modeling of unsaturated flow without invoking the Richards equation and associated hydraulic functions. We adapt a formalism originally developed for foam “free drainage” (drainage under gravity) or “forced drainage” (infiltration front motion) to a class of unsaturated flows in porous media that require a few input parameters only (mean channel corner angle, air entry value, and porosity) for certain initial and boundary conditions. We demonstrate that the reduction in capillary channel cross section yields a consistent description of self‐regulating internal fluxes toward attainment of the so‐called “field capacity” in soil and provides an alternative method for interpretation of outflow experiments for prescribed pressure boundary conditions. Additionally, the geometrically explicit formulation provides a more intuitive picture of capillary flows across textural boundaries (changes in channel cross section and number of channels). The foam drainage methodology expands the range of tools available for analyses of unsaturated flow processes and offers more realistic links between liquid configuration and flow dynamics in unsaturated porous media.
饱和土和非饱和土的各向异性因子
DOI：
--
发表时间：
2006
期刊：
影响因子：
--
作者：
S. Assouline;Dani Or
通讯作者：
Dani Or
DOI：
--
发表时间：
1990
期刊：
影响因子：
--
作者：
T. Yeh;D. Harvey
通讯作者：
D. Harvey
模拟非平衡压力条件下高度非均质介质中不饱和流动的非局部理查兹方程
影响因子：
2.8
作者：
I. Neuweiler;D. Erdal;M. Dentz
通讯作者：
M. Dentz