Related Experiment Video
Updated: Jul 5, 2026

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
Gas-driven subharmonic waves in a vibrated two-phase granular material
J-P Matas1, J Uehara, R P Behringer
1Department of Physics & Center for Nonlinear and Complex Systems, Duke University, Durham, NC 27708-0305, USA. matas@hmg.inpg.fr
Abstract:
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.
More Related Videos
06:51Microparticle Manipulation by Standing Surface Acoustic Waves with Dual-frequency Excitations
Published on: August 21, 2018
09:00Visualization of Failure and the Associated Grain-Scale Mechanical Behavior of Granular Soils under Shear using Synchrotron X-Ray Micro-Tomography
Published on: September 29, 2019
Related Concept Videos
Standing Waves
Sound Waves: Resonance
Forced Oscillations
Sound as Pressure Waves
The pressure fluctuation depends on the difference in displacements between the successive points in the...
Standing Waves in a Cavity
Vibrating Concrete