Rectified motion in an asymmetric channel: the role of hydrodynamic interactions with walls

TL;DR

This paper investigates how hydrodynamic interactions with walls influence the rectified motion of a Brownian particle in an asymmetric channel under oscillating forces, revealing that such interactions reduce the efficiency of the ratchet mechanism.

Contribution

It introduces a numerical analysis that incorporates long-range hydrodynamic effects in the study of particle dynamics in asymmetric channels, extending previous models that only considered short-range collisions.

Findings

Hydrodynamic interactions decrease ratchet efficiency.

Channel geometry significantly affects rectified current.

Long-range wall effects are crucial for accurate modeling.

Abstract

Dynamics of a Brownian particle in an asymmetric micro-channel that is subjected to an external oscillating force is numerically analyzed. In addition to the elastic collisions with the walls that are kind of short range interactions, the long range hydrodynamic influences of the walls have been considered. We demonstrate how the geometrical parameters of the channel change the rectified current of the particle. As a result of numerical calculations, we show that long range hydrodynamic interactions with walls, decrease the efficiency of the Brownian ratchet.