2018 Impact factor 1.686
Soft Matter and Biological Physics


Eur. Phys. J. E 4, 29-32

A note on the screening of hydrodynamic interactions, in electrophoresis, and in porous media

D. Long and A. Ajdari.

Laboratoire de Physico-Chimie Théorique, E.s.a. CNRS 7083, ESPCI, 10 rue Vauquelin F-75231 Paris Cedex 05, France

long@lps.u-psud.fr

(Received 23 March 2000)

Abstract
We consider two situations where hydrodynamic interactions are said to be "screened": hydrodynamics in a gel or in a porous medium, and electrophoresis in an electrolyte. We focus on the corresponding Green functions, and show that the flow fields are similar in the two cases. Contrarily to statements often made, the fluid velocity decays algebraically with distance ( $\simeq 1/r^3$), i.e. not exponentially. We point out that the pressure fields are different in the two cases.

PACS
82.45.+z - Electrochemistry and electrophoresis.
47.15.Gf - Low-Reynolds-number (creeping) flows.
47.15.Rq - Laminar flows in cavities.


© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2001