Transition from Jamming to Clogging in Heterogeneous Environments

Jamming describes a transition from a flowing or liquid state to a solid or rigid state in a loose assembly of particles such as grains [1]. In contrast, clogging describes the ceasing of particulate matter flow through a bottleneck [2]. It is not clear how to distinguish jamming from clogging, nor is it known whether they are distinct phenomena or fundamentally the same. We examine an assembly of disks moving through a random obstacle array and identify a transition from clogging to jamming behavior as the disk density increases. The clogging transition has characteristics of an absorbing phase transition, with the disks evolving into a heterogeneous phase separated clogged state after a critical diverging transient time. In contrast, jamming is a rapid process in which the disks form a homogeneous motionless packing, with a rigidity length scale that diverges as the jamming density is approached. We show how the relaxation times and transient time exponents change at the clogging-jamming boundary and demonstrate that clogged systems reach a stationary state that is independent of the system density while jammed states are strongly dependent on the system density.
[1] Liu, A.J. & Nagel, S.R. Ann Rev Cond Mat Phys 1, 347 (2010).
[2] Zuriguel, I. et al. Sci Rep 4, 7324 (2014).