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Inwardly Rotating Spirals in a Nonoscillatory Medium.
Harunori N Yoshikawa1, Christian Mathis1, Shu Satoh2
1Université Côte d'Azur, CNRS, UMR 7351, Laboratoire J.-A. Dieudonné, 06108 Nice Cedex 02, France.
Physical Review Letters
|April 24, 2019
Summary
Researchers observed spontaneous spiral patterns forming on a liquid film's free surface. These patterns, resembling rotating arms, result from phase locking and periodic liquid discharge, explained by a cellular automaton model.
Area of Science:
- Fluid dynamics
- Pattern formation
- Instability phenomena
Background:
- Free surface flow instabilities can lead to complex dynamic behaviors.
- Rayleigh-Taylor instability affects downward-facing liquid films.
- Liquid curtains are a known discharge phenomenon from unstable films.
Purpose of the Study:
- To investigate the spontaneous formation of spiral patterns on a downward-facing liquid film.
- To understand the underlying mechanisms of pattern generation and liquid discharge.
- To model the observed phenomena using a computational approach.
Main Methods:
- Observation of spontaneous spiral pattern formation at the free surface of a horizontal liquid film.
- Analysis of the Rayleigh-Taylor instability's role in liquid discharge.
- Development and application of a phenomenologically constructed cellular automaton for simulation.
Main Results:
- Spontaneous formation of inwardly rotating spiral patterns was observed.
- These patterns originate from the film's circular periphery.
- The cellular automaton model successfully reproduced the spiral patterns, attributing them to phase locking and periodic discharge.
Conclusions:
- Spiral patterns in liquid films arise from phase locking phenomena.
- Periodic liquid discharge at a constant flow rate drives the pattern formation.
- Cellular automaton modeling provides a valid framework for understanding these complex fluid dynamics.
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