Rheology of dense granular flows for elongated particles.
Rheology of dense granular flows for elongated particles.
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DOI：
10.1103/physreve.96.062903
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发表时间：
2017-10
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通讯作者：
Dániel Nagy;P. Claudin;T. Börzsönyi;E. Somfai
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作者：
Dániel Nagy;P. Claudin;T. Börzsönyi;E. Somfai
我们通过 3D 数值模拟研究无摩擦球柱的致密颗粒流的流变学。与球形颗粒的情况一样，有效摩擦 μ 是惯性数 I 的增函数，我们系统地研究了 μ 对颗粒长宽比 Q 以及法向应力差、体积分数和配位数的依赖性。我们特别表明，准静态摩擦系数与 Q 是非单调的：从球形情况 Q=1 开始，它首先急剧增加，在 Q≃1.05 附近达到最大值，然后缓慢下降，直到 Q=3，在 Q≃2 处通过其初始值。我们通过分析颗粒周围耗散接触的分布，为这种意想不到的行为提供了微观解释：与球体相比，稍微拉长的颗粒增强了其中心圆柱带中的接触，而在较大的纵横比下，颗粒倾向于通过其半球形帽处的优先接触来排列和耗散。
We study the rheology of dense granular flows for frictionless spherocylinders by means of 3D numerical simulations. As in the case of spherical particles, the effective friction μ is an increasing function of the inertial number I, and we systematically investigate the dependence of μ on the particle aspect ratio Q, as well as that of the normal stress differences, the volume fraction, and the coordination number. We show in particular that the quasistatic friction coefficient is nonmonotonic with Q: from the spherical case Q=1, it first sharply increases, reaches a maximum around Q≃1.05, and then gently decreases until Q=3, passing its initial value at Q≃2. We provide a microscopic interpretation for this unexpected behavior through the analysis of the distribution of dissipative contacts around the particles: as compared to spheres, slightly elongated grains enhance contacts in their central cylindrical band, whereas at larger aspect ratios particles tend to align and dissipate by preferential contacts at their hemispherical caps.