Abstract
The terminal velocities of spheres falling in six flocculated china-clay suspensions have been measured, and corrections applied for the retarding effect of the walls of the containing vessel. The drag experienced by a sphere in the Reynolds number range of 250 to 40 000 is explained in terms of an unsheared envelope of the suspension which surrounds the sphere and which decreases in diameter as the velocity increases, disappearing completely at a velocity which depends primarily upon the concentration of the suspension.