Compaction of vibrated monodisperse granular materials in a cylindrical container

Abstract

Vibration tends to increase the packing fraction of granular materials. This phenomenon, called compaction, is relevant in many industrial processes and is well-studied but is not yet a fully understood complex phenomenon. Previous works established that compaction is sensitive to dimensionless acceleration Γ of the vibration. The Γ has two components, amplitude and frequency. In this work, we performed a discrete element method (DEM) simulation of the compaction of monodisperse granular materials inside a vibrating cylindrical container. We studied the dependence of parameters of the inverse logarithmic equation (i.e., ⟨ρ_f⟩, ⟨B⟩, and ⟨τ ⟩) proposed in Knight et al. on Γ and the sensitivity of these dependences on whether Γ is tuned by varying the frequency or amplitude. The results suggest ⟨ρ_f⟩ depends on Γ, and this relationship is only observed when Γ is tuned by varying the amplitude. The results for relating ⟨B⟩ and Γ are mixed, with one characterization region suggesting that ⟨B⟩ depends on Γ when Γ is tuned by varying the amplitude, while the rest show that ⟨B⟩ does not depend on Γ regardless of the tuning of Γ. Similarly, the results for relating ⟨τ ⟩ and Γ are mixed, with one characterization region suggesting that ⟨τ ⟩ depends on Γ when Γ is tuned by varying the amplitude, while the rest show that ⟨τ ⟩ does not depend on Γ regardless of the tuning of Γ. These findings not only has practical implications in handling materials but in theory-building as well, i.e., using dimensionless quantities to formulate equations.