Anomalous distribution functions in sheared suspensions

TL;DR

This paper studies the velocity distribution functions in sheared suspensions, revealing deviations from classical distributions and demonstrating scaling behavior with shear rate, concentration, and viscosity through simulations and theory.

Contribution

It introduces a combined simulation and theoretical analysis showing how velocity PDFs in sheared suspensions deviate from Maxwell-Boltzmann and scale with key parameters.

Findings

PDFs exhibit Gaussian cores and exponential tails

Distributions scale with shear rate, concentration, and viscosity

Excellent agreement between theory and simulation

Abstract

We investigate velocity probability distribution functions (PDF) of sheared hard-sphere suspensions. As observed in our Stokes flow simulations and explained by our single-particle theory, these PDFs can show pronounced deviations from a Maxwell-Boltzmann distribution. The PDFs are symmetric around zero velocity and show a Gaussian core and exponential tails over more than six orders of magnitude of probability. Following the excellent agreement of our theory and simulation data, we demonstrate that the distribution functions scale with the shear rate, the particle volume concentration, as well as the fluid viscosity.