ANISOTROPIC PARTICLE DISTRIBUTION IN DILUTE SUSPENSIONS OF SOLID SPHERES IN CYLINDRICAL COUETTE-FLOW

The pair distribution function of the particles in a noncolloidal suspension was for the first time measured experimentally. Evidence of anisotropy in dilute suspensions of solid spheres is presented. Suspensions of polystyrene spheres in silicone oils with volume fractions 0. 01 less than equivalent to c less than equivalent to 0. 05 were subjected to cylindrical Couette flow in a Weissenberg Rheogoniometer. Using automatic data gathering and processing techniques specially developed for this purpose, an analysis of the relative positions of the spheres showed that (under shear) the spheres were not uniformly distributed in the suspension, but rather were arranged anisotropically.