Model of heap formation in vibrated gravitational suspensions
Model of heap formation in vibrated gravitational suspensions
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DOI：
10.1103/physreve.92.053016
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发表时间：
2015-11-23
影响因子：
2.4
通讯作者：
Sano, Masaki
中科院分区：
文献类型：
--
作者：
Ebata, Hiroyuki;Sano, Masaki
在垂直振动的稠密悬浮液中，已经发现了几种局部结构，如堆、稳定孔、膨胀孔和复制孔。由于重力压力的作用，倾斜的自由液面很难保持，这些结构的机理还不能直观地理解。在本文中，作为一个候选的驱动机制，我们专注于固体壁面上的边界条件：与垂直振动同步的slipnonslip切换边界条件。应用润滑近似，从Oldrophil-B流体模型出发，导出了流体厚度随时间的演化方程。在我们的模型中，我们表明，最初平坦的流体层变得不稳定的亚临界方式，堆和对流出现。所得结果与实验观测结果一致。我们还发现，当底部稍微倾斜时，堆会爬上斜坡。我们发现，粘弹性增强堆的形成和爬坡的堆上的斜坡。
In vertically vibrated dense suspensions, several localized structures have been discovered, such as heaps, stable holes, expanding holes, and replicating holes. Because an inclined free fluid surface is difficult to maintain because of gravitational pressure, the mechanism of those structures is not understood intuitively. In this paper, as a candidate for the driving mechanism, we focus on the boundary condition on a solid wall: the slipnonslip switching boundary condition in synchronization with vertical vibration. By applying the lubrication approximation, we derived the time evolution equation of the fluid thickness from the Oldroyd-B fluid model. In our model we show that the initially flat fluid layer becomes unstable in a subcritical manner, and heaps and convectional flow appear. The obtained results are consistent with those observed experimentally. We also find that heaps climb a slope when the bottom is slightly inclined. We show that viscoelasticity enhances heap formation and climbing of a heap on the slope.