Euclidean geometry and the flow of generalized liquids

Abstract

This paper is a review of recent research on liquid viscosity, derived from structural studies based on aggregates of spheres in space, and from non-linear continuum mechanics. The use of Voronoi polyhedra and the Delaunay graph to characterize irregular aggregates is briefly described, and the theory due to Bernal of a liquid as an aggregate of spheres is reviewed. The Bernal polyhedra, and an elementary rate theory where the activation volume is essentially a second rank tensor, give expressions for viscosity and for stress in lineal flow that are compatible with the non-linear theory of stress of Coleman and Noll.