Reichhardt C, Reichhardt C J O
Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Soft Matter. 2021 Feb 19;17(6):1548-1557. doi: 10.1039/d0sm01714k.
We model collective disk flow though a square array of obstacles as the flow direction is changed relative to the symmetry directions of the array. At lower disk densities there is no clogging for any driving direction, but as the disk density increases, the average disk velocity decreases and develops a drive angle dependence. For certain driving angles, the flow is reduced or drops to zero when the system forms a heterogeneous clogged state consisting of high density clogged regions coexisting with empty regions. The clogged states are fragile and can be unclogged by changing the driving angle. For large obstacle sizes, we find a uniform clogged state that is distinct from the collective clogging regime. Within the clogged phases, depinning transitions can occur as a function of increasing driving force, with intermittent motion appearing just above the depinning threshold. The clogging is robust against the random removal or dilution of the obstacle sites, and the disks are able to form system-spanning clogged clusters even under increasing dilution. If the dilution becomes too large, however, the clogging behavior is lost.
我们将通过方形障碍物阵列的集体盘流建模，因为流的方向相对于阵列的对称方向发生了变化。在较低的盘密度下，对于任何驱动方向都不会出现堵塞，但随着盘密度的增加，平均盘速度会降低并呈现出驱动角依赖性。对于某些驱动角，当系统形成由高密度堵塞区域与空区域共存的异质堵塞状态时，流会减小或降至零。堵塞状态很脆弱，可以通过改变驱动角来解除堵塞。对于较大的障碍物尺寸，我们发现了一种与集体堵塞状态不同的均匀堵塞状态。在堵塞阶段内，随着驱动力的增加，可能会发生脱钉转变，在脱钉阈值之上会出现间歇性运动。堵塞对障碍物位置的随机移除或稀释具有鲁棒性，并且即使在稀释增加的情况下，盘也能够形成跨越整个系统的堵塞簇。然而，如果稀释变得太大，堵塞行为就会消失。
