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Coupled Leidenfrost states as a monodisperse granular clock
Rui Liu1, Mingcheng Yang1, Ke Chen1
1Beijing National Laboratory for Condensed Matter Physics and CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190.
Physical Review. E
|September 15, 2016
Summary
Granular beads in coupled columns can create a novel granular clock. This oscillation emerges from a density-inverted state, amplified by column asymmetry, and is explained by a two-parameter Andronov-Hopf bifurcation.
Area of Science:
- Physics
- Complex Systems
- Nonlinear Dynamics
Background:
- Granular materials exhibit complex behaviors not fully captured by traditional fluid or solid mechanics.
- The Leidenfrost effect, typically observed with liquids on hot surfaces, has analogs in granular systems.
Purpose of the Study:
- To investigate the oscillatory behavior of granular beads in coupled columns.
- To identify the conditions and mechanisms that trigger and sustain these oscillations.
- To develop a theoretical model explaining the observed granular clock phenomenon.
Main Methods:
- Event-driven molecular dynamics simulations of monodisperse granular beads.
- Analysis of density-inverted states and phase relaxation dynamics.
- Linear stability analysis and numerical solutions of a minimal two-phase model.
Main Results:
- A novel granular clock oscillation was observed in coupled granular columns.
- Oscillations are triggered by a density-inverted state (high-density cluster supported by a low-density phase).
- Small asymmetries between columns are amplified, leading to giant oscillations within an intermediate coupling strength range.
Conclusions:
- The granular clock phenomenon is driven by the interplay between density inversion, phase dynamics, and inter-column coupling.
- The oscillation mechanism can be understood as a switchable two-parameter Andronov-Hopf bifurcation.
- A minimal two-phase model successfully reproduces the simulated oscillatory dynamics.
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