Spatiotemporal patterns in reaction-diffusion system and in a vibrated granular bed
- Univ. of Texas, Austin, TX (United States)
Experiments on a quasi-two-dimensional reaction-diffusion system reveal transitions from a uniform state to stationary hexagonal, striped, and rhombic spatial patterns. For other reactor conditions lamellae and self-replicating spot patterns are observed. These patterns form in continuously fed thin gel reactors that can be maintained indefinitely in well-defined nonequilibrium states. Reaction-diffusion models with two chemical species yield patterns similar to those observed in the experiments. Pattern formation is also being examined in vertically oscillated thin granular layers (typically 3-30 particle diameters deep). For small acceleration amplitudes, a granular layer is flat, but above a well-defined critical acceleration amplitude, spatial patterns spontaneously form. Disordered time-dependent granular patterns are observed as well as regular patterns of squares, stripes, and hexagons. A one-dimensional model consisting of a completely inelastic ball colliding with a sinusoidally oscillating platform provides a semi-quantitative description of most of the observed bifurcations between the different spatiotemporal regimes.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- OSTI ID:
- 175499
- Report Number(s):
- CONF-9505200-; ON: DE96000983; TRN: 96:003533
- Resource Relation:
- Conference: 13. symposium on energy engineering sciences, Argonne, IL (United States), 15-17 May 1995; Other Information: PBD: [1995]; Related Information: Is Part Of Thirteenth symposium on energy engineering sciences: Proceedings. Fluid/thermal processes, systems analysis and control; PB: 275 p.
- Country of Publication:
- United States
- Language:
- English
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