# Ripples and Shear Bands in Plowed Granular Media - Physics > Fluid Dynamics

Abstract: Monodisperse packings of dry, air-fluidized granular media typically existbetween volume fractions from $\Phi$= 0.585 to 0.64. We demonstrate that thedynamics of granular drag are sensitive to volume fraction $\Phi$ and theirexists a transition in the drag force and material deformation from smooth tooscillatory at a critical volume fraction $\Phi {c}=0.605$. By dragging asubmerged steel plate 3.81 cm width, 6.98 cm depth through $300 \mu m$ glassbeads prepared at volume fractions between 0.585 to 0.635 we find that below$\Phi {c}$ the media deformation is smooth and non-localized while above$\Phi {c}$ media fails along distinct shear bands. At high $\Phi$ thegeneration of these shear bands is periodic resulting in the ripples on thesurface. Work funded by The Burroughs Wellcome Fund and the Army Research LabMAST CTA

Author: Nick Gravish, Paul Umbanhowar, Daniel I. Goldman

Source: https://arxiv.org/