Publications [#245477] of Robert P. Behringer

Papers Published
  1. Matas, J-P; Uehara, J; Behringer, RP, Gas-driven subharmonic waves in a vibrated two-phase granular material., The European Physical Journal E - Soft Matter and Biological Physics, vol. 25 no. 4 (April, 2008), pp. 431-438 [18421417], [doi] .

    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.