Grains and gas flow: molecular dynamics with hydrodynamic interactions

Area of Science:

• Physics
• Fluid Dynamics
• Computational Science

Background:

• Granular flows are complex, involving interactions between solid particles and fluid phases.
• Accurate simulation of these flows often requires computationally intensive methods.

Purpose of the Study:

• To develop a computationally efficient model for granular flows with hydrodynamic interactions.
• To validate the model's ability to reproduce key phenomena in sedimenting and fluidized particle beds.

Main Methods:

• A coarse-grained hydrodynamic model using a local Darcy law for pressure.
• Explicit grain dynamics simulated with event-driven molecular dynamics.
• Simulation of sedimenting and fluidized particle beds.

Main Results:

• The model correctly captures the sharp upper front in sedimenting particle beds.
• Simulations reproduce theoretical predictions for particle movement during sedimentation.
• The model generates bubbles in fluidized beds with shapes matching experimental observations.
• Observed bubble merging in fluidized beds is also reproduced.

Conclusions:

• The proposed simplified model offers an efficient approach to simulating granular flows.
• The model successfully captures essential qualitative features of sedimenting and fluidized granular systems.
• This method provides a valuable tool for studying complex granular dynamics without high computational cost.