Anomalous distribution functions in sheared suspensions

¹  Institute for Computational Physics - Pfaffenwaldring 27, D-70569 Stuttgart, Germany, EU
²  Computational Physics, IfB - Schafmattstr. 6, ETH Zürich, CH-8093 Zürich, Switzerland
³  Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory Los Alamos, NM 87545, USA

Received: 16 May 2008
Accepted: 16 June 2008

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.