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Soret driven convection in a colloidal solution heated from above at very large solutal Rayleigh number

R. Cerbino·A. Vailati·M. Giglio
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Abstract

Convection in a colloidal suspension with a large negative separation ratio is studied experimentally by heating from above. Shadowgraph observation at very large solutal Rayleigh numbers are reported as a function of time. Fast relaxation oscillations are reported for the root mean square value of the shadowgraph intensity. While pure fluids exhibit a transition to turbulent convection for Rayleigh number of about 10^6, stable spoke-pattern planform with up and down columnar flows are observed up to solutal Rayleigh numbers of the order of 10^9. It is suggested that the surprising stability of the planform against turbulence is due to nonlinear focusing arising from the concentration dependence of the diffusion coefficient.

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R. Cerbino, A. Vailati, M. Giglio. 2002-10-02. Soret driven convection in a colloidal solution heated from above at very large solutal Rayleigh number. https://doi.org/10.1103/physreve.66.055301

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