Switching of non-equilibrium depletion force caused by blockade effect

Abstract

The concentration-dependent switching of the non-equilibrium depletion forces between obstacles in an interacting Brownian gas flow is presented. It is shown that this switching is caused by the blockade effect for the gas particles. With increasing equilibrium gas concentration, the gas particles blockade causes the obstacle wake inversion (trace profile turn-over) that, in turn, leads to the change of sign of dissipative interaction. Some non-linear effects such as formation of a cavity-like sparse wake behind the obstacle and the dissipative pairing effect are discussed briefly. The results are obtained within the lattice gas model in the mean-field approximation.