Title: Distribution of unjamming times of a vibrated granular hopper

Author (Talk): Sumit Kumar Birwa, TIFR Centre for Interdisciplinary Sciences

Abstract:

We present a computational study of a 2D gravity-driven flow of bidisperse soft spheres in a vertical hopper. For a small range of opening sizes, the flow eventually clogs; both experiments and simulations agree that the time to clog is exponentially distributed with a characteristic mean time. When the hopper is unjammed through periodic vertical vibrations, the times to unjam obey a power law in which the exponents depend on the amplitude of vibration and size of the opening at the base. We wish to understand what gives rise to this broad distribution of unjamming times and whether this can be characterized by the strength of the contact network in the clogged state. We find that the arches play an important role in determining the stability of the jammed configurations.We are currently working on a model description of the dynamics of this unjamming process.