Shear-driven flow of athermal, frictionless, spherocylinder suspensions in two dimensions: Stress, jamming, and contacts
Shear-driven flow of athermal, frictionless, spherocylinder suspensions in two dimensions: Stress, jamming, and contacts
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二维无热、无摩擦、球圆柱悬架的剪切驱动流动：应力、干扰和接触
DOI：
10.1103/physreve.100.032906
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发表时间：
2019
影响因子：
2.4
通讯作者：
Teitel, S.
中科院分区：
文献类型：
--
作者：
Marschall, Theodore A.;Teitel, S.
我们使用数值模拟来研究由以固定有限速率施加的均匀稳态剪切应变驱动的无热、无摩擦、软核二维球圆柱的双分散混合物的流动。能量耗散是通过相对于均匀剪切的主流体的粘性阻力发生的，从而给出了非布朗悬浮液中流动的简单模型，并产生了牛顿流变学。我们研究了相互作用的球柱产生的压力和偏剪切应力，作为填充分数、应变率和测量颗粒非球面性的参数的函数；考虑从近圆盘到细长棒的范围。我们考虑应力张量的各向异性方向、宏观摩擦以及输运系数的发散增加到干扰转变。通过对干扰上方的 Herschel-Bulkley 流变学进行现象学分析，我们将其估计为非球面度的函数，并表明，with 的变化是流变学差异的主要原因；当绘制为时，不同质量的流变曲线一致。然而，对我们最细长粒子的散度的详细尺度分析表明，球柱的干扰转变可能与圆盘的干扰转变处于不同的普遍性类别。我们还计算了系统中每个粒子的接触数量，并表明干扰时的值是一个非单调函数，它总是小于均衡值。我们测量了相对于球柱脊柱的极角处每单位表面长度的接触概率分布，发现该分布似乎在 处发散，从而为球柱的几乎消失的小平坦侧面上的接触给出了有限的极限概率。最后，我们考虑平均接触力的变化作为颗粒表面位置的函数。
We use numerical simulations to study the flow of a bidisperse mixture of athermal, frictionless, soft-core two-dimensional spherocylinders driven by a uniform steady-state shear strain applied at a fixed finite rate. Energy dissipation occurs via a viscous drag with respect to a uniformly sheared host fluid, giving a simple model for flow in a non-Brownian suspension and resulting in a Newtonian rheology. We study the resulting pressureand deviatoric shear stressof the interacting spherocylinders as a function of packing fraction, strain rate, and a parameterthat measures the asphericity of the particles;is varied to consider the range from nearly circular disks to elongated rods. We consider the direction of anisotropy of the stress tensor, the macroscopic friction, and the divergence of the transport coefficientasis increased to the jamming transition. From a phenomenological analysis of Herschel-Bulkley rheology above jamming, we estimateas a function of asphericityand show that the variation ofwithis the main cause for differences in rheology asis varied; when plotted as, rheological curves for differentqualitatively agree. However, a detailed scaling analysis of the divergence offor our most elongated particles suggests that the jamming transition of spherocylinders may be in a different universality class than that of circular disks. We also compute the number of contacts per particlein the system and show that the value at jammingis a nonmonotonic function ofthat is always smaller than the isostatic value. We measure the probability distribution of contacts per unit surface lengthat polar anglewith respect to the spherocylinder spine and find that asthis distribution seems to diverge at, giving a finite limiting probability for contacts on the vanishingly small flat sides of the spherocylinder. Finally, we consider the variation of the average contact force as a function of location on the particle surface.