Flow and clogging of particles in shaking random obstacles

Area of Science:

• Physics, specifically statistical mechanics and soft matter physics.
• Complex systems and non-equilibrium phenomena.
• Particle dynamics in disordered media.

Background:

• Understanding particle transport in disordered environments is crucial for various applications.
• The influence of particle properties (passive, active, polar) and obstacle dynamics on transport is not fully understood.
• Differential mobility and clogging are key phenomena in confined particle flows.

Purpose of the Study:

• To investigate the transport dynamics of passive, active, and polar particles in a random obstacle array.
• To analyze the effects of static and moving obstacles on particle mobility and clogging.
• To identify conditions that optimize particle transport and minimize clogging.

Main Methods:

• Numerical simulations were employed to model particle trajectories.
• The study considered a range of direct current (dc) drift forces and particle densities.
• Obstacle configurations included static arrays and arrays with synchronous shaking (longitudinal and transverse).

Main Results:

• Negative differential mobility was observed for low particle densities with static obstacles, while positive differential mobility occurred at high densities.
• Passive particles exhibited higher mobility than active or polar particles, which were prone to trapping.
• Optimal shaking frequency and amplitude for moving obstacles maximized average particle velocity.
• Transverse shaking was more effective than longitudinal shaking in reducing clogging.

Conclusions:

• Particle type and obstacle dynamics critically influence transport in random arrays.
• Polar alignment significantly impedes particle mobility.
• Moving obstacles, particularly with transverse shaking, offer a viable strategy to enhance transport and mitigate clogging.