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Updated: Jul 13, 2026
11:03
An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
Velocity correlations in dense granular flows observed with internal imaging.
Ashish V Orpe1, Arshad Kudrolli
1Department of Physics, Clark University, Worcester, Massachusetts 01610, USA.
Physical Review Letters
|August 7, 2007
Summary
Dense granular flows in silos exhibit velocity correlations akin to elastic hard-sphere liquids. These findings reveal insights into granular material dynamics and fluid-like behavior.
Area of Science:
- Physics
- Rheology
- Granular Materials Science
Background:
- Granular flows exhibit complex behaviors that are not fully understood.
- Previous studies have focused on different flow regimes or materials.
Purpose of the Study:
- To investigate the velocity correlations in uniform dense granular flows within a silo.
- To compare granular flow dynamics to established liquid models.
Main Methods:
- Utilized a fluorescent refractive-index-matched interstitial fluid for measurements.
- Analyzed velocity autocorrelation functions and mean square displacements.
- Examined flow in a regime dominated by enduring grain contact.
Main Results:
- Velocity correlations in granular flows resemble the hydrodynamic response of elastic hard-sphere liquids.
- Observed negative short-time correlation and slow oscillatory decay in bulk grain velocity.
- Identified weak spatial correlations and caging dynamics, with boundary effects noted.
Conclusions:
- Dense granular flows in silos display liquid-like hydrodynamic properties.
- The findings suggest a potential universal behavior in dense granular flows.
- Boundary effects significantly alter the observed correlation dynamics.
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