## Abstract

We conduct molecular dynamics simulations of athermal systems undergoing boundary-driven planar shear flow in two and three spatial dimensions. We find that these systems possess nonlinear mean velocity profiles when the velocity u of the shearing wall exceeds a critical value u_{c}. Above u _{c}, we also show that the packing fraction and mean-square velocity profiles become spatially dependent with dilation and enhanced velocity fluctuations near the moving boundary. In systems with overdamped dynamics, u_{c} is only weakly dependent on packing fraction φ. However, in systems with underdamped dynamics, u_{c} is set by the speed of shear waves in the material and tends to zero as φ approaches φ_{c}, which is near random close packing at small damping. For underdamped systems with φ < φ_{c}, u_{c} is zero; thus they possess nonlinear velocity profiles at any nonzero u.

Original language | English (US) |
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Article number | 016001 |

Journal | Physical Review Letters |

Volume | 94 |

Issue number | 1 |

DOIs | |

State | Published - Jan 14 2005 |

## All Science Journal Classification (ASJC) codes

- Physics and Astronomy(all)