Hydrodynamic granular segregation induced by boundary heating and shear

Area of Science:

• Physics
• Statistical Mechanics
• Soft Matter

Background:

• Granular gases exhibit complex behaviors under external forces.
• Thermal gradients can induce particle segregation in granular systems.
• Understanding segregation mechanisms is crucial for controlling granular flows.

Purpose of the Study:

• To investigate impurity segregation in a driven granular gas subjected to a thermal gradient.
• To develop a theoretical criterion for segregation based on granular hydrodynamics.
• To validate theoretical predictions using computational simulations.

Main Methods:

• Analytical solution of the inelastic Boltzmann equation to determine transport coefficients.
• Development of a segregation criterion using Navier-Stokes granular hydrodynamics.
• Validation through Monte Carlo and molecular dynamics simulations.

Main Results:

• A segregation criterion was derived in terms of tracer diffusion transport coefficients.
• The dependence of transport coefficients on system parameters (masses, sizes, restitution) was explicitly determined.
• Theoretical predictions were accurately validated by simulations.

Conclusions:

• Navier-Stokes granular hydrodynamics provides accurate segregation criteria for driven granular gases.
• The model remains valid even under conditions of strong shearing and inelasticity.
• This work offers a theoretical framework for predicting and controlling impurity segregation in granular systems.