论文标题
双向悬架流中堵塞
Clogging in bidirectional suspension flow
论文作者
论文摘要
通常通过收缩在颗粒流中的堵塞过渡观察到由于限制而突然停止运动。我们提出了一个简单的实验的结果，以阐明两种物种的双向流中相似的过渡，其中两种具有不同密度的宏观颗粒被限制在管中，并悬浮在中间密度的流体中。反流的谷物用作移动障碍物和堵塞，而由于限制而没有拱形形成。我们测量堵塞或干扰概率$ j $作为固定通道宽度$ d $ d = $ 3 $ - $ 7 $ d $的每个物种$ n $的粒子的函数，其中$ d $是粒子直径。 $ j（n）$表现出sigmoidal依赖性，并在单个曲线$ j（n/d^3）$上崩溃，表明过渡发生在临界密度。数据是由概率模型很好地拟合的，该模型是由先前的收缩流动，假设晶粒进入堵塞区域，其固定概率可以产生堵塞状态。一个准二维实验提供了对界面形状的洞察力，并且我们在大通道宽度下确定了雷利 - 泰勒的不稳定性。
The sudden arrest of motion due to confinement is commonly observed via the clogging transition in the flow of particles through a constriction. We present results of a simple experiment to elucidate a similar transition in the bidirectional flow of two species in which two species of macroscopic particles with different densities are confined in a tube and suspended in a fluid of intermediate density. Counterflowing grains serve as mobile obstacles and clogging occurs without arch formation due to confinement. We measure the clogging or jamming probability $J$ as a function of number of particles of each species $N$ in a fixed channel length for channel widths $D = $ 3$-$7$d$, where $d$ is the particle diameter. $J(N)$ exhibits a sigmoidal dependence and collapses on a single curve $J(N/D^3)$ indicating the transition occurs at a critical density. Data is well-fit by a probabilistic model motivated by prior constriction flows which assumes grains enter the clogging region with a fixed probability to produce a clogging state. A quasi-two-dimensional experiment provides insight into the interface shape and and we identify a Rayleigh-Taylor instability at large channel widths.
