Hydrodynamic interaction in confined geometries

TL;DR

This paper reviews recent theoretical and experimental insights into how confinement affects hydrodynamic interactions between particles in liquids, highlighting that these interactions generally remain long-ranged except in specific channel confinements.

Contribution

It provides a unifying theoretical framework explaining the effects of confinement on hydrodynamic interactions in various geometries.

Findings

Hydrodynamic interactions are long-ranged under confinement.

Confinement effects depend on geometry, especially in rigid linear channels.

A unifying description accounts for diverse experimental and theoretical results.

Abstract

This article gives an overview of recent theoretical and experimental findings concerning the hydrodynamic interaction between liquid-embedded particles in various confined geometries. A simple unifying description emerges, which accounts for the various findings based on the effect of confinement on conserved fields of the embedding liquid. It shows, in particular, that the hydrodynamic interaction under confinement remains long-ranged, decaying algebraically with inter-particle distance, except for the case of confinement in a rigid linear channel.