Caitano R, Guerrero B V, González R E R, Zuriguel I, Garcimartín A
Depto. de Física y Mat. Apl., Facultad de Ciencias, Universidad de Navarra, E-31080 Pamplona, Spain.
Laboratório de Sistemas Complexos e Universais, Departamento de Física, Universidade Federal Rural de Pernambuco, Recife-PE, CEP 52171-900, Brasil.
Phys Rev Lett. 2021 Oct 1;127(14):148002. doi: 10.1103/PhysRevLett.127.148002.
The existence of a transition from a clogged to an unclogged state has been recently proposed for the flow of macroscopic particles through bottlenecks in systems as diverse as colloidal suspensions, granular matter, or live beings. Here, we experimentally demonstrate that, for vibrated granular media, such a transition genuinely exists, and we characterize it as a function of the outlet size and vibration intensity. We confirm the suitability of the "flowing parameter" as the order parameter, and we find out that the rescaled maximum acceleration of the system should be replaced as the control parameter by a dimensionless velocity that can be seen as the square root of the ratio between kinetic and potential energy. In all the investigated scenarios, we observe that, for a critical value of this control parameter S_{c}, there seems to be a continuous transition to an unclogged state. The data can be rescaled with this critical value, which, as expected, decreases with the orifice size D. This leads to a phase diagram in the S-D plane in which clogging appears as a concave surface.
最近有人提出，在诸如胶体悬浮液、颗粒物质或生物等各种系统中，宏观颗粒通过瓶颈时存在从堵塞状态到畅通状态的转变。在这里，我们通过实验证明，对于振动颗粒介质，这种转变确实存在，并且我们将其表征为出口尺寸和振动强度的函数。我们证实了“流动参数”作为序参量的适用性，并且我们发现，系统的重新标度化的最大加速度应由一个无量纲速度代替作为控制参数，该无量纲速度可视为动能与势能之比的平方根。在所有研究的情况下，我们观察到，对于这个控制参数(S_{c})的临界值，似乎存在向畅通状态的连续转变。数据可以用这个临界值进行重新标度化，正如预期的那样，该临界值随孔口尺寸(D)减小。这导致了(S - D)平面中的相图，其中堵塞表现为一个凹面。
