Signature of transition in granular flow through apertures

Abstract

We employ computations to examine transition in granular flow, right above an aperture, in a silo draining under gravity. We show that the energy dissipation rate exhibits a well-defined peak near the aperture. Tracing locations of maximum dissipation rate describes an arch, signifying flow transition. We present a correlation between the transition boundary and outlet using the arguments of self-similarity and geometric similarity, suggesting the spatial non-monotonicity of the dissipation rate to be a signature of flow transition. Utilizing the aforementioned similarity criteria, we also explore the kinetic pressure as a marker of transition in granular flow.