Orifice jamming of fluid-driven granular flow

摘要

The three-dimensional jamming of neutrally buoyant monodisperse, bidisperse, and tridisperse mixtures ofnparticles flowing through a restriction under fluid flow has been studied. During the transient initial accumulationnof particles at the restriction, a low probability of a jamming event is observed, followed by a transition tona steady-state flowing backlog of particles, where the jamming probability per particle reaches a constant.nAnalogous to the steady-state flow in gravity-driven jams, this results in a geometric distribution describing thennumber of particles that discharge prior to a jamming event.We develop newmodels to describe the transition fromnan accumulation to a steady-state flow, and the jamming probability after the transition has occurred. Predictionsnof the behavior of the geometric distribution see the log-probability of a jam occurring proportionally to (R2n2n− 1),nwhere R2 is the ratio of opening diameter to the second moment number average particle diameter. This behaviornis demonstrated to apply to more general restriction shapes, and collapses for all mixture compositions for thenrestriction sizes tested.