Session MV: Swimming V: Micro-organisms II
8:00 AM–10:10 AM, Tuesday, November 24, 2009
Room: 205A-D
Chair: Timothy J. Pedley, University of Cambridge
Abstract ID: BAPS.2009.DFD.MV.3
Abstract: MV.00003 : Three-Dimensional Pattern Formation in Flowing Suspensions of Swimming Particles
8:26 AM–8:39 AM
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Abstract 
Authors:
Amir Alizadeh Pahlavan
(Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign)
David Saintillan
(Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign)
Suspensions of self-propelled particles, such as swimming micro-organisms, are known to undergo complex dynamics as a result of hydrodynamic interactions. Using the kinetic theory recently developed by Saintillan and Shelley (``Instabilities, pattern formation, and mixing in active suspensions'', \textit{Physics of Fluids} \textbf{20}, 123304, 2008), we investigate the three-dimensional pattern formation occurring in suspensions of active particles. Our numerical simulations confirm the results of the linear stability analysis of Saintillan et al., and the long-time nonlinear behavior is shown to be characterized by the formation of strong density fluctuations, which merge and break up in time in a quasiperiodic fashion. These complex motions result in very efficient fluid mixing, which we quantify by means of a multiscale mixing norm. The effects of an external shear flow on the pattern formation are also investigated using both simulations and a stability analysis.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2009.DFD.MV.3