Self-diffusion of spherocylindrical particles flowing under non-uniform shear rate

Area of Science:

• Physics
• Materials Science
• Computational Science

Background:

• Studying particle dynamics in granular flows is crucial for understanding complex material behaviors.
• Non-spherical particles and non-uniform shear rates present significant challenges in modeling granular systems.

Purpose of the Study:

• To numerically investigate the self-diffusion of spherocylindrical particles on an inclined plane.
• To establish a relationship between particle diffusion and local shear rates in granular flows.
• To identify conditions where diffusion deviates from shear rate dependence.

Main Methods:

• Utilized the discrete element method (DEM) for numerical simulations.
• Performed simulations across various particle aspect ratios and inclination angles.
• Employed coarse-graining to analyze spatial shear rate profiles and computed diffusion coefficients.

Main Results:

• Identified spatial regions where particle diffusivity strongly correlates with the local shear rate.
• Developed a scaling law between diffusion coefficients (D) and shear rates (γ̇) using an effective particle size (d⊥).
• Observed deviations from shear rate correlation in areas with non-linear shear rate variation and asymmetric velocity distributions.

Conclusions:

• The study provides a framework for understanding self-diffusion in sheared granular flows of non-spherical particles.
• The proposed scaling law offers a predictive tool for granular material behavior under specific flow conditions.
• Non-linear shear variations significantly impact particle diffusion dynamics, leading to complex flow behaviors.