Viscous forces and bulk viscoelasticity near jamming.
Karsten Baumgarten1, Brian P Tighe
1Delft University of Technology, Process & Energy Laboratory, Leeghwaterstraat 39, 2628 CB Delft, The Netherlands. k.baumgarten@tudelft.nl.
Soft Matter
|October 18, 2017
Summary
The study reveals that the viscous force law significantly impacts the mechanical response of jammed soft spheres, affecting dynamic scaling and frequency dependence. This sensitivity is linked to how damping interacts with non-affine motion near jamming.
Area of Science:
- Soft matter physics
- Rheology
- Statistical mechanics
Background:
- Weakly jammed packings of soft spheres exhibit complex elastic and viscous behaviors.
- Existing models for particle interactions, particularly viscous ones, vary.
- Understanding these behaviors is crucial for material science and fluid dynamics.
Purpose of the Study:
- To numerically investigate the complex shear modulus (G*) of jammed packings.
- To analyze the influence of different viscous force laws on G*.
- To elucidate the relationship between viscous damping and system dynamics near jamming.
Main Methods:
- Numerical measurement of the complex shear modulus (G*).
- Simulation of jammed packings with various viscous force laws.
- Analysis of damping effects on particle-pair and particle-fluid velocities.
Main Results:
- A surprising sensitivity of G* to the specific viscous force law was observed.
- The presence of dynamic critical scaling and its exponents are dependent on the force law.
- Viscous damping's coupling to non-affine motion dictates this sensitivity.
Conclusions:
- The choice of viscous force law critically influences the rheological properties of jammed soft matter.
- Non-affine motion plays a key role in the frequency-dependent response.
- Further research into specific force laws is needed for accurate modeling.
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