Slowing-down of non-equilibrium concentration fluctuations in confinement

Cédric Giraudet, Henri Bataller, Yifei Sun, Aleksandar Donev, José María Ortiz De Zárate, Fabrizio Croccolo

Research output: Contribution to journalArticle

Abstract

Fluctuations in a fluid are strongly affected by the presence of a macroscopic gradient making them long-ranged and enhancing their amplitude. While small-scale fluctuations exhibit diffusive lifetimes, moderate-scale fluctuations live shorter because of gravity. In this letter we explore fluctuations of even larger size, comparable to the extent of the system in the direction of the gradient, and find experimental evidence of a dramatic slowing-down of their dynamics. We recover diffusive behavior for these strongly confined fluctuations, but with a diffusion coefficient that depends on the solutal Rayleigh number. Results from dynamic shadowgraph experiments are complemented by theoretical calculations and numerical simulations based on fluctuating hydrodynamics, and excellent agreement is found. Hence, the study of the dynamics of non-equilibrium fluctuations allows to probe and measure the competition of physical processes such as diffusion, buoyancy and confinement, i.e. the ingredients included in the Rayleigh number, which is the control parameter of our system.

Original languageEnglish (US)
Article number60013
JournalEPL
Volume111
Issue number6
DOIs
StatePublished - Oct 9 2015

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Rayleigh number
shadowgraph photography
gradients
buoyancy
ingredients
diffusion coefficient
hydrodynamics
gravitation
life (durability)
probes
fluids
simulation

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Giraudet, C., Bataller, H., Sun, Y., Donev, A., Ortiz De Zárate, J. M., & Croccolo, F. (2015). Slowing-down of non-equilibrium concentration fluctuations in confinement. EPL, 111(6), [60013]. https://doi.org/10.1209/0295-5075/111/60013

Slowing-down of non-equilibrium concentration fluctuations in confinement. / Giraudet, Cédric; Bataller, Henri; Sun, Yifei; Donev, Aleksandar; Ortiz De Zárate, José María; Croccolo, Fabrizio.

In: EPL, Vol. 111, No. 6, 60013, 09.10.2015.

Research output: Contribution to journalArticle

Giraudet, C, Bataller, H, Sun, Y, Donev, A, Ortiz De Zárate, JM & Croccolo, F 2015, 'Slowing-down of non-equilibrium concentration fluctuations in confinement', EPL, vol. 111, no. 6, 60013. https://doi.org/10.1209/0295-5075/111/60013
Giraudet C, Bataller H, Sun Y, Donev A, Ortiz De Zárate JM, Croccolo F. Slowing-down of non-equilibrium concentration fluctuations in confinement. EPL. 2015 Oct 9;111(6). 60013. https://doi.org/10.1209/0295-5075/111/60013
Giraudet, Cédric ; Bataller, Henri ; Sun, Yifei ; Donev, Aleksandar ; Ortiz De Zárate, José María ; Croccolo, Fabrizio. / Slowing-down of non-equilibrium concentration fluctuations in confinement. In: EPL. 2015 ; Vol. 111, No. 6.
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