Hydrodynamics of fluid-solid coexistence in dense shear granular flow

Area of Science:

• Physics
• Materials Science
• Fluid Dynamics

Background:

• Granular materials exhibit complex flow behaviors under shear.
• Navier-Stokes granular hydrodynamics describes these flows.
• Shear viscosity in granular systems shows unique density-dependent divergence.

Purpose of the Study:

• To investigate dense rapid shear flow in granular systems.
• To develop and validate new constitutive relations for granular flow.
• To analyze the stability of uniform shear flow and map its phase diagram.

Main Methods:

• Application of Navier-Stokes granular hydrodynamics.
• Development of interpolation formulas for constitutive relations.
• Linear stability analysis of uniform shear flow.
• Validation using event-driven molecular dynamics (MD) simulations.

Main Results:

• Shear viscosity divergence occurs at lower densities than other constitutive relations.
• New interpolation formulas accurately represent dilute to dense granular flow.
• High particle inelasticity induces a transition from uniform shear flow to a two-phase flow.
• The two-phase flow consists of a dense, solidlike cluster within fluid layers.

Conclusions:

• The study provides a comprehensive phase diagram for granular shear flow.
• The findings are experimentally verifiable through MD simulations.
• Understanding these transitions is crucial for predicting granular material behavior in dense, rapid flows.