Gas-driven subharmonic waves in a vibrated two-phase granular material

Jean-Philippe Matas (1) , Jun Uehara (2) , R. P. Behringer (2)

1 LEGI - Laboratoire des Écoulements Géophysiques et Industriels [Grenoble]
2 Department of Physics

Vibrated powders exhibit striking phenomena: subharmonic waves, oscillons, convection, heaping, and even bubbling. We demonstrate novel rectangular profile subharmonic waves for vibrated granular material, that occur uniquely in the two-phase case of grains, and a fluid, such as air. These waves differ substantially from those for the gas-free case, exhibit different dispersion relations, and occur for specific shaking parameters and air pressure, understandable with gas-particle flow models. These waves occur when the gas diffusively penetrates the granular layer in a time comparable to the shaker period. As the pressure is lowered towards P=0, the granular-gas system exhibits a Knudsen regime. This instability provides an opportunity to quantitatively test models of two-phase flow.

Mots clés: Granular systems; instabilities

Domaines: Mécanique des fluides [physics.class-ph]; Mécanique des fluides [physics.class-ph]

Jean-Philippe Matas, Jun Uehara, R. P. Behringer. Gas-driven subharmonic waves in a vibrated two-phase granular material. European Physical Journal E: Soft matter and biological physics, 2008, 25, pp.431. ⟨10.1140/epje/i2007-10310-5⟩. ⟨hal-00352667⟩