Anomalous hydrodynamic interaction in a quasi-two-dimensional suspension

Abstract

We have studied the correlated Brownian motion of micron-sized particles suspended in water and confined between two plates. The hydrodynamic interaction between the particles exhibits three anomalies. (i) The transverse coupling is negative, i.e., particles exert "anti-drag" on one another when moving perpendicular to their connecting line. (ii) The interaction decays with inter-particle distance r as 1/r^2, faster than in unconfined suspensions but slower than near a single wall. (iii) At large distances the pair interaction is independent of concentration within the experimental accuracy. The confined suspension thus provides an unusual example of long-range, yet essentially pairwise correlations even at high concentration. These effects are shown to arise from the two-dimensional dipolar form of the flow induced by single-particle motion.

4 pages, 4 figures

References in corpus (1)

• Screened hydrodynamic interaction in a narrow channel

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• Screening by symmetry of long-range hydrodynamic interactions of polymers confined in sheets
• Hydrodynamic interaction in quasi-two-dimensional suspensions
• Correlated particle dynamics in concentrated quasi-two-dimensional suspensions
• Flow fields in soap films: relating surface viscosity and film thickness
• An analysis of the far-field response to external forcing of a suspension in Stokes flow in a parallel-wall channel
• Lubrication approximation for micro-particles moving along parallel walls