Length scales and self-organization in dense suspension flows

Area of Science:

• Rheology
• Soft Matter Physics
• Computational Fluid Dynamics

Background:

• Dense non-Brownian suspensions show diverging viscosity and correlation lengths near jamming.
• Microscopic mechanisms of dissipation and their link to correlation length remain unclear.

Purpose of the Study:

• Investigate the microscopic origins of dissipation in suspension flows.
• Connect suspension flow properties to the rigidity transition in floppy networks.
• Explain the decoupling between viscosity and velocity correlation length.

Main Methods:

• Developed an analogy between suspension flows and network rigidity transitions.
• Derived critical properties near the rigidity transition.
• Performed numerical simulations to validate theoretical predictions.

Main Results:

• Suspension flows were found to be close to the rigidity transition.
• A decoupling between viscosity and velocity correlation length (ξ) was observed.
• Numerical confirmation of predicted scaling laws for characteristic lengths (l(c), l(r)) and strain scale (δγ) based on particle pressure (p).

Conclusions:

• The proximity to the rigidity transition governs suspension flow behavior.
• Particle pressure dictates key length scales and strain decorrelation.
• Understanding these relationships is crucial for predicting suspension dynamics.