Characterization of the Clogging Transition in Vibrated Granular Media

Area of Science:

• Physics
• Complex Systems
• Materials Science

Background:

• A transition between clogged and unclogged states has been theorized for macroscopic particle flow through bottlenecks.
• This phenomenon is observed across diverse systems, including colloidal suspensions, granular matter, and biological systems.

Purpose of the Study:

• To experimentally demonstrate and characterize the clogging-unclogging transition in vibrated granular media.
• To identify and validate suitable order and control parameters for this transition.
• To construct a phase diagram illustrating the transition as a function of system parameters.

Main Methods:

• Experimental setup involving vibrated granular media with variable outlet sizes and vibration intensities.
• Measurement of system dynamics, including particle flow and acceleration.
• Analysis using a proposed 'flowing parameter' as the order parameter and a dimensionless velocity as the control parameter.

Main Results:

• The existence of a genuine transition from a clogged to an unclogged state in vibrated granular media was confirmed.
• A dimensionless velocity, representing the ratio of kinetic to potential energy, was identified as the appropriate control parameter.
• A critical value (Sc) for this control parameter was found, below which a continuous transition to an unclogged state occurs.
• The critical value decreases with increasing orifice size (D).

Conclusions:

• The study experimentally validates the flow transition in granular media, providing a robust understanding of clogging dynamics.
• A new phase diagram in the S-D plane was established, characterizing clogging as a concave surface.
• The findings offer insights into the fundamental physics of granular flow and jamming phenomena.