Oscillations and defect turbulence in a shallow fluidized bed

D. K. Clark; L. S. Tsimring; I. S. Aranson

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Oscillations and defect turbulence in a shallow fluidized bed

D. K. Clark·L. S. Tsimring·I. S. Aranson

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Abstract

We report an experimental study of the dynamics of an air-fluidized thin granular layer. Near-onset behavior of this shallow fluidized bed was described in the earlier paper (Tsimring et al, 1999). Above the threshold of fluidization the system exhibits a Hopf bifurcation as the layer starts to oscillate at a certain frequency due to a feedback between the layer dilation and the airflow drag force. After application of temporal band-pass filtering of this frequency we discovered the spatio-temporal dynamics in the form of defect turbulence. This type of dynamics is natural for spatio-temporal systems close to the threshold of a Hopf bifurcation. At high flow rates, low-frequency short-wavelength structures appear in addition to the long-wavelength excitations. A simple model describing the instability and occurrence of oscillations in a shallow fluidized bed, is proposed.

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D. K. Clark, L. S. Tsimring, I. S. Aranson. 2000-05-06. Oscillations and defect turbulence in a shallow fluidized bed. https://arxiv.org/abs/nlin/0005010

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