Force and Flow Transition in Plowed Granular Media

Nick Gravish, Paul B. Umbanhowar, Daniel I. Goldman
2010 Physical Review Letters  
We use plate drag to study the response of granular media to localized forcing as a function of volume fraction, ϕ. A bifurcation in the force and flow occurs at the onset of dilatancy, ϕ_c. Below ϕ_c rapid fluctuations in the drag force, F_D, are observed. Above ϕ_c fluctuations in F_D are periodic and increase with ϕ. Velocity field measurements indicate that the bifurcation in F_D results from the formation of stable shear bands above ϕ_c which are created and destroyed periodically during
more » ... ag. A friction-based model captures the dynamics for ϕ>ϕ_c.
doi:10.1103/physrevlett.105.128301 pmid:20867678 fatcat:s2qkkgw7tjad3bmpmbe7gq3r3e