Particle migrations in suspension flows

Abstract

An apparatus is described whereby the distribution of particles in a neutrally buoyant suspension of spheres flowing through a tube may be measured. The discovery of a narrow region of high concentration near to the tube wall, and the behaviour of this ‘wall peak’ at various concentrations and positions along the length of the tube are described. An explanation for this behaviour is put forward in terms of the formation of the peak by interaction of spheres with the tube entrance, and of the formation within this peak of necklace-like strings of particles.