RT Journal Article
T1 Fluctuations in fluids in thermal nonequilibrium states below the convective Rayleigh-Benard instability
A1 Ortiz De Zárate Leira, José María
A1 Sengers, Jan V.
AB Starting from the linearized fluctuating Boussinesq equations we derive an expression for the structure factor of fluids in stationary convection-free thermal nonequilibrium. states, taking into account both gravity and finite-size effects. It is demonstrated how the combined effects of gravity and finite size cause the structure factor to go through a maximum value as a function of the wave number q. The appearance of this maximum is associated with a crossover from a q^-4 dependence for larger q to a q^2 dependence for very small q. The relevance of this theoretical result for the interpretation of light scattering and shadowgraph experiments is elucidated. The relationship with studies on various aspects of the problem by other investigators is discussed. The paper thus provides a unified treatment for dealing with fluctuations in fluid layers subjected to a stationary temperature gradient regardless of the sign of the Rayleigh number R, provided that R is smaller than the critical value R_c associated with the appearance of Rayleigh-Benard convection.
PB Elsevier
SN 0378-4371
YR 2001
FD 2001-11-01
LK https://hdl.handle.net/20.500.14352/59853
UL https://hdl.handle.net/20.500.14352/59853
LA eng
NO © 2001 Elsevier Science B.VThe authors acknowledge some valuable discussions with G. Ahlers, D.S. Cannell, T.R. Kirkpatrick, R. Pérez Cordón and M.G. Velarde. The research at the University of Marylandis supportedby the Chemical Sciences, Geosciences andBiosciences Division of the OIce of Basic Energy Sciences of the US Department of Energy under Grant No. DE-FG-02-95ER14509. J.V.S. acknowledges the hospitality of the Departamento deFísica Aplicada I, Universidad Complutense de Madrid, where the manuscript was completed.
NO OIce of Basic Energy Sciences of the US Department of Energy
DS Docta Complutense
RD 29 jun 2025