Inelastic collapse in simple shear flow of a granular medium

Area of Science:

• Physics
• Computational Physics
• Granular Mechanics

Background:

• Inelastic collapse is a known phenomenon in unforced granular flow simulations.
• The behavior of inelastic collapse in driven systems, specifically simple shear flow, requires further investigation.

Purpose of the Study:

• To investigate the occurrence and characteristics of inelastic collapse in two-dimensional, hard-sphere simulations of simple shear flow.
• To determine the influence of key parameters like restitution coefficient, solids fraction, and particle number on inelastic collapse in driven systems.

Main Methods:

• Conducted two-dimensional, hard-sphere simulations of simple shear flow.
• Varied the coefficient of restitution (r), solids fractions (nu), and number of particles (N).
• Analyzed particle behavior, focusing on collision patterns and string formation preceding collapse.

Main Results:

• Inelastic collapse is an integral feature of simple shear flow, characterized by particle strings colliding repeatedly before collapse.
• Collapse is more probable with lower r, higher nu, and higher N.
• Driven systems exhibit greater resistance to inelastic collapse compared to unforced systems.
• A dimensionless number, V*, related to initial velocities versus steady-state velocity, differentiates transient behavior.

Conclusions:

• Inelastic collapse occurs in driven simple shear flow, with specific conditions favoring its occurrence.
• The sheared system demonstrates increased resilience to collapse compared to unforced systems.
• The dimensionless number V* is a critical parameter in understanding the transition from nondriven-like to driven-system behavior.