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An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
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Transitions between multiple dynamical states in a confined dense active-particle system.
Pallab Sinha Mahapatra1, Ajinkya Kulkarni2, Sam Mathew2
1Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036, India.
Physical Review. E
|July 16, 2017
Summary
This study investigates active swimmers in fluid, revealing distinct nonequilibrium states. Transitions between these states depend on swimmer thrust, showing unique behaviors at low and high forces.
Area of Science:
- Physics of complex fluids
- Soft matter physics
- Statistical mechanics
Background:
- Active matter systems exhibit emergent collective behaviors.
- Understanding nonequilibrium steady states is crucial for soft matter physics.
- Dense suspensions of microswimmers are model systems for active matter.
Purpose of the Study:
- To investigate the collective motion of dense active swimmer suspensions.
- To identify and characterize different nonequilibrium steady states.
- To analyze the transitions between these states as a function of swimmer thrust.
Main Methods:
- Modeling swimmers as soft spheres in a viscous fluid.
- Applying constant propelling thrust aligned with particle velocity.
- Analyzing total dissipation to characterize state transitions.
Main Results:
- Observed multiple distinct nonequilibrium steady states.
- Characterized transitions via changes in exponent at low thrust.
- Identified hysteretic transitions between ordered and disordered states at high thrust.
Conclusions:
- The collective motion of active swimmers is highly sensitive to thrust magnitude.
- Transitions between steady states exhibit distinct behaviors at different thrust regimes.
- Hysteresis in transitions suggests complex dynamics in dense active suspensions.
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