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A first-principle mechanism for particulate aggregation and self-assembly in stratified fluids
Roberto Camassa1, Daniel M Harris2, Robert Hunt3
1Department of Mathematics, University of North Carolina, Chapel Hill, Chapel Hill, NC, 27599, USA. camassa@amath.unc.edu.
Nature Communications
|December 22, 2019
Summary
Particles in fluid systems can self-assemble into large aggregates without adhesion, driven by gravity and fluid dynamics. This unexpected mechanism involves toroidal flows and attractive forces, leading to organized disc-like structures.
Area of Science:
- Fluid dynamics
- Particle physics
- Self-assembly phenomena
Background:
- Gravitational settling and aggregation are fundamental in nature.
- Understanding particle behavior in stratified fluid systems is crucial.
Purpose of the Study:
- To observe and mathematically model a novel self-assembly mechanism for suspended particles.
- To elucidate the role of fluid dynamics and particle geometry in aggregate formation.
Main Methods:
- Mathematical modeling of particle behavior in stratified fluids.
- Observation of particle self-assembly and aggregate formation.
- Control experiments and quantitative simulations.
Main Results:
- Identified a new mechanism for particle self-assembly without adhesion.
- Discovered toroidal flows generated by solute diffusion, boundaries, and geometry.
- Observed collective particle motion forming disc-like aggregates with increasing attractive forces.
Conclusions:
- Particle self-assembly in stratified fluids can occur via adhesionless mechanisms.
- Toroidal flows are key to generating attractive forces and collective organization.
- Simulations accurately predict observed self-assembly dynamics.
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