Trains of particles in finite-Reynolds-number pipe flow

Abstract

In finite-Reynolds-number pipe flow, we have observed long-lived trains of particles aligned with the flow. These trains are located on the Segré-Silberberg equilibrium position which is an annulus close to the wall at the large Reynolds numbers investigated. The effect seems to be controlled by inertia and more precisely by the particle Reynolds number. © 2004 American Institute of Physics.