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arXiv 1807.00249cond-mat.soft
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弹性壳填料的流体流动

Fluid flow through packings of elastic shells

Pawel Gniewek, Oskar Hallatschek

摘要:

多孔材料中的流体输运通常在地质样品(土壤、沉积物等)中进行研究。或理想化的系统,但是流体流过由基本上应变的颗粒组成的压实颗粒材料仍然相对未被探索。作为填补这一空白的一步,我们研究了一个模型的液体输送包装的可变形的弹性壳,使用有限元和格子玻尔兹曼方法。我们发现,流体流动突然消失的材料的孔隙率下降到一个临界值以下,和流动障碍表现出逾渗过渡的功能。我们进一步表明,流体流动可以被捕获的一个简化的渗透率模型,其中复杂的多孔材料被替换为一组无序的毛细管,分布和形状的渗滤过渡。为此,我们用数值方法探讨了水力弯曲度$\rmτ_H$的发散和水力半径$\rm R_h$的减小,因为接近渗流阈值。我们解释我们的结果的尺度预测来自应用于随机填充的领域的渗流理论。

英文摘要:

Fluid transport in porous materials is commonly studied in geological samples (soil, sediments etc.) or idealized systems, but the fluid flow through compacted granular materials, consisting of substantially strained granules, remains relatively unexplored. As a step towards filling this gap, we study a model of liquid transport in packings of deformable elastic shells using Finite Element and Lattice-Boltzmann methods. We find that the fluid flow abruptly vanishes as the porosity of the material falls below a critical value, and the flow obstruction exhibits features of a percolation transition. We further show that the fluid flow can be captured by a simplified permeability model in which the complex porous material is replaced by a collection of disordered capillaries, which are distributed and shaped by the percolation transition. To that end, we numerically explore the divergence of hydraulic tortuosity $\rmτ_H$ and the decrease of a hydraulic radius $\rm R_h$ as the percolation threshold is approached. We interpret our results in terms of scaling predictions derived from the percolation theory applied to random packings of spheres.

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