Related Experiment Video
Updated: Jul 14, 2026
11:03
An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
Caging dynamics in a granular fluid.
P M Reis1, R A Ingale, M D Shattuck
1Benjamin Levich Institute, The City College of the City University of New York, 140th Street and Convent Avenue, New York, New York 10031, USA. preis@pmmh.espci.fr
Physical Review Letters
|May 16, 2007
Summary
In granular fluids, increasing particle density causes temporary particle trapping, mimicking dense liquids. This study reveals precursors to glass transitions, even without a true glass transition, due to crystallization.
Area of Science:
- Physics
- Materials Science
- Soft Matter Physics
Background:
- Granular fluids exhibit complex dynamics influenced by particle interactions and density.
- Understanding particle motion in dense systems is crucial for fluid dynamics and materials science.
- Glassy dynamics, characterized by slow relaxation and particle trapping, are typically observed in dense molecular liquids and colloids.
Purpose of the Study:
- To experimentally investigate the caging motion in uniformly heated granular fluids.
- To analyze particle trajectories and identify features associated with dense liquids and glassy dynamics.
- To explore the role of filling fraction on particle dynamics and structural arrest.
Main Methods:
- Experimental setup involving a uniformly heated granular fluid.
- Systematic variation of filling fractions (varphi).
- Statistical analysis of particle trajectories to quantify caging and diffusive behavior.
Main Results:
- At low filling fractions, classic diffusive fluid behavior was observed.
- At higher filling fractions, temporary cages formed, trapping particles.
- Observed features in particle trajectories resemble those in dense molecular liquids and colloids.
- Precursors to glassy dynamics were identified despite the absence of a glass transition.
Conclusions:
- Granular fluids exhibit cage formation and particle trapping at high densities.
- The system displays characteristics of dense liquids and precursors to glassy dynamics.
- Crystallization plays a role in structural arrest, influencing particle dynamics.
Related Concept Videos
01:11Design Example: Forces in Sluice Gate
In hydraulic engineering, sluice gates are essential for managing water flow through channels, reservoirs, and irrigation systems. Sluice gates, acting as vertical barriers, regulate water by adjusting the gate's opening height, which changes the velocity and pressure of water flowing beneath the gate. Understanding the forces involved is crucial to designing sluice gates that can withstand dynamic pressure differences, especially when the gate is closed or partially open.
Key variables in...
Key variables in...
01:10First Law: Particles in One-dimensional Equilibrium
Newton's first law of motion states that a body at rest remains at rest, or if in motion, remains in motion at constant velocity, unless acted on by a net external force. It also states that there must be a cause for any change in velocity (a change in either magnitude or direction) to occur. This cause is a net external force. For example, consider what happens to an object sliding along a rough horizontal surface. The object quickly grinds to a halt, due to the net force of friction. If we...
01:18Fluid Movement Between Compartments
The force applied by fluids against a surface, known as hydrostatic pressure, initiates the transfer of fluid among different compartments. Within our blood vessels, the blood's hydrostatic pressure is a result of the heart's pumping action. At the arteriolar end of capillaries, hydrostatic pressure (capillary blood pressure) exceeds the opposing colloid osmotic pressure created primarily by plasma proteins like albumin. This discrepancy in pressure propels plasma and nutrients from the...
01:24Protein Diffusion in the Membrane
Proteins show rotational as well as lateral diffusion across the membrane. The lateral diffusion of proteins was confirmed through the cell fusion experiment where mouse and human cells were fused, resulting in hybrid cells. When the human and mouse cells fused, the specific membrane proteins on human and mouse cells were marked with the red and green-fluorescent markers, respectively. Initially, the red and green fluorescence was located on the respective hemisphere of the cell. As time...
01:18First Law: Particles in Two-dimensional Equilibrium
Recall that a particle in equilibrium is one for which the external forces are balanced. Static equilibrium involves objects at rest, and dynamic equilibrium involves objects in motion without acceleration; but it is important to remember that these conditions are relative. For instance, an object may be at rest when viewed from one frame of reference, but that same object would appear to be in motion when viewed by someone moving at a constant velocity.
Newton's first law tells us about the...
Newton's first law tells us about the...
01:19Capillarity in Fluid
Capillarity describes the movement of liquid in small spaces without external forces acting on it. The capillarity is driven by surface tension and adhesive interactions between the liquid and surrounding solid surfaces. This effect is often seen in narrow tubes, porous materials, and fine particles.
Surface tension is crucial to capillarity. It results from cohesive forces between liquid molecules at the liquid-air boundary, forming a skin that resists external forces. When the capillary tube...
Surface tension is crucial to capillarity. It results from cohesive forces between liquid molecules at the liquid-air boundary, forming a skin that resists external forces. When the capillary tube...