Flow Dynamics of Vibrated Dense Granular Materials in the Presence of Ambient Gas

Results are presented from a numerical study examining the flow dynamics of condensed granular materials in the presence of an interstitial gas in a narrow gap between two concentric cylindrical buckets subjected to sinusoidal oscillation in the vertical direction of the form z = Asin(ωt), where the parameter Γ = Aω²/g exceeds a critical value, Γ_c, above which the system becomes fluidized. Using a recently developed expression for the stress tensor of particle phase, a set of conservation equations were derived for the particle and fluid phases interacting via an interfacial drag force. Numerical integration of the continuum equations for the granular material in buckets revealed that above Γ_c, granular materials may exhibit liquid-like behavior and convection can occur creating a heap similar to that previously observed experimentally.