RT Journal Article
T1 Slowing-down of non-equilibrium concentration fluctuations in confinement
A1 Giraudet, Cédric
A1 Bataller, Henri
A1 Sun, Yifei
A1 Donev, Aleksander
A1 Ortiz De Zárate Leira, José María
A1 Croccolo, Fabrizio
AB 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.
PB European Physical Society
SN 0295-5075
YR 2015
FD 2015-09
LK https://hdl.handle.net/20.500.14352/24282
UL https://hdl.handle.net/20.500.14352/24282
LA eng
NO © European Physical Society.We acknowledge fruitful discussions with ALBERTO VAILATI, DORIANO BROGIOLI, ROBERTO CERBINO and JAN SENGERS. JMOZ acknowledges support from the UCM-Santander Research Grant PR6/13-18867 during a sabbatical leave in Anglet. AD was supported in part by the U.S. National Science Foundation under grant DMS-1115341 and the Office of Science of the U.S. Department of Energy through Early Career award No. DE-SC0008271.
NO United States Goverment
NO National Science Foundation (NSF), EE.UU.
NO Early Career Award, Department of Energy, EE.UU.
NO Universidad Complutense de Madrid (UCM)
NO Banco Santander Central Hispano (BSCH)
DS Docta Complutense
RD 17 abr 2025