Chapter 7 - Thermal nonequilibrium fluctuations in one-component-fluid layers

Abstract

This chapter reviews thermal nonequilibrium fluctuations in one-component-fluid layers. The nonequilibrium structure factor is considered for a fluid layer between two free boundaries for which explicit analytic expressions can be obtained. For a fluid layer between two free boundaries, the nonequilibrium dynamic structure factor is obtained by substituting into the general expression. It is found that for the dimensionless nonequilibrium enhancement of the fluctuations in the case of rigid boundaries, a more compact result is obtained in the approximation of small-scattering angles. The exact analytical expressions for the limiting behavior of the nonequilibrium enhancement of the structure factor for rigid boundaries, are obtained. It is observed that the Galerkin method is equivalent to a finite-mode approach with approximate decay rates and corresponding modes. The advantage of this scheme is that, at the lowest order, it produces analytical expressions for the decay rates and the nonequilibrium structure factor. It is found that the Galerkin approximation reproduces for both limits the correct asymptotic behavior qualitatively. The contribution of nonequilibrium fluctuations to heat transfer is also elaborated.