Bounds on the drag for creeping flow of an ellis fluid past an assemblage of spheres

Upper and lower bounds for the creeping flow of an Ellis fluid past an assemblage of solid spheres are obtained using a combination of Happel's free surface model and variational principles. The arithmetic mean of the bounds agrees closely with the experimental data on flow through porous media. For Ellis numbers approaching infinity, the analysis also predicts the bounds for a power law fluid. © 1976.