Anomalous Pressure in Fluctuating Shear Flow

Abstract

We investigate how the pressure in fluctuating shear flow depends on the shear rate $S$ and on the system size $L$ by studying fluctuating hydrodynamics under shear conditions. We derive anomalous forms of the pressure for two limiting values of the dimensionless parameter $λ=SL^2/ν$, where $ν$ is the kinematic viscosity. In the case $λ\ll 1$, the pressure is not an intensive quantity because of the influence of the long-range spatial correlations of momentum fluctuations. In the other limit $λ\gg 1$, the long-range correlations are suppressed at large distances, and the pressure is intensive. In this case, however, there is the interesting effect that the non-equilibrium correction to the pressure is proportional to $S^{3/2}$, which was previously obtained with the projection operator method [K. Kawasaki and J. D. Gunton, Phys. Rev. {\bf A 8}, 2048, (1973)].