Author:
WILSON HELEN J.,DAVIS ROBERT H.
Abstract
We consider the flow of a dilute suspension of equisized solid spheres in a viscous
fluid. The viscosity of such a suspension is dependent on the volume fraction, c, of
solid particles. If the particles are perfectly smooth, then solid spheres will not come
into contact, because lubrication forces resist their approach. In this paper, however,
we consider particles with microscopic surface asperities such that they are able to
make contact. For straining motions we calculate the O(c2) coefficient of the resultant
viscosity, due to pairwise interactions. For shearing motions (for which the viscosity
is undetermined because of closed orbits on which the probability distribution is
unknown) we calculate the c2 contribution to the normal stresses
N1 and N2. The
viscosity in strain is shown to be slightly lower than that for perfectly smooth spheres,
though the increase in the O(c) term caused by the increased effective radius due to
surface asperities will counteract this decrease. The viscosity decreases with increasing
contact friction coefficient. The normal stresses N1 and N2 are zero if the surface
roughness height is less than a critical value of 2.11 × 10−4 times the particle radius,
and then become negative as the roughness height is increased above this value. N1
is larger in magnitude than N2.
Publisher
Cambridge University Press (CUP)
Subject
Mechanical Engineering,Mechanics of Materials,Condensed Matter Physics
Cited by
60 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献