Concentrated active suspensions: Kinetic theory, linear stability and numerical simulations

ORAL

Abstract

We study concentrated suspensions of self-propelled rod-like particles using a kinetic model which accounts for local hydrodynamic and steric interactions. We report a base state transition from an isotropic to a nematic orientation distribution beyond a critical effective volume fraction consistent with the Doi-Edwards theory for passive rod-like particles (Doi and Edwards 1986). We analyze the kinetic model linearized near the isotropic and nematic basestates and show that steric interactions have a destabilizing effect causing both pusher and puller suspensions to be subject to instabilities. These predictions from the linear theory are confirmed using fully nonlinear three-dimensional numerical simulations of the kinetic equations, which also demonstrate large-scale fluctuations of number density and nematic order parameter.

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Authors

  • Barath Ezhilan

    Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA

  • Michael Shelley

    Courant Institute of Mathematical Sciences, New York University, New York, New York 10012, USA, New York University, Courant Institute, New York University, Courant Institute

  • David Saintillan

    Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA, University of Illinois at Urbana-Champaign, Department of Mechanical Science and Engineering, University of Illinois, Urbana-Champaign