Bubble propagation in a pipe filled with sand - art. no. 021509

Granular flow with strong hydrodynamic interactions has been studied experi mentally. Experiments have been carried out to study the movement of a sing le bubble in an inclined tube filled with glass beads and air. A maximum bu bble velocity was found at an inclined angle theta (m). The density variati ons in the sand were measured by capacitance measurements, and a decompacti fication zone was observed just above the bubble when the inclination angle theta was larger than theta (m). The length of the decompactification fron t increased with increasing inclination angle and disappeared for angles sm aller than theta (m). Both pressure and visualization experiments were carr ied out and compared with the density measurements.