Bubble propagation in a pipe filled with sand

Abstract

Granular flow with strong hydrodynamic interactions has been studied experimentally. Experiments have been carried out to study the movement of a single bubble in an inclined tube filled with glass beads and air. A maximum bubble velocity was found at an inclined angle [formula presented] The density variations in the sand were measured by capacitance measurements, and a decompactification zone was observed just above the bubble when the inclination angle [formula presented] was larger than [formula presented] The length of the decompactification front increased with increasing inclination angle and disappeared for angles smaller than [formula presented] Both pressure and visualization experiments were carried out and compared with the density measurements. © 2001 The American Physical Society.