Particle pressure in a sheared suspension: a bridge from osmosis to granular dilatancy.
The normal stress exerted by particles in a sheared suspension is measured by analogy with a method used to measure osmotic pressure in solutions. Particles in a liquid are confined by a fine screen to a gap between two vertical concentric cylinders, the inner of which rotates. Pressure in the liquid is sensed either by a manometer or by a pressure transducer across the screen. The particles are large enough so that Brownian motion and equilibrium osmotic pressure are vanishingly small. The measured pressure yields the shear-induced particle pressure Pi, the nonequilibrium continuation of equilibrium osmotic pressure. For volume fractions 0.3< or =varphi< or =0.5, Pi is strongly dependent on varphi, and linear in shear rate. Comparisons of the measured particle pressure with modeling and simulation show good agreement.
Deboeuf
Angélique
A
Univ Pierre et Marie Curie-Paris6, Univ Paris-Sud, CNRS, Laboratoire FAST, Campus universitaire d'Orsay, 91405 Orsay Cedex, France.
Gauthier
Georges
G
Martin
Jérôme
J
Yurkovetsky
Yevgeny
Y
Morris
Jeffrey F
JF