Polar patterns in active fluids

Luca Giomi, M. Cristina Marchetti

Research output: Contribution to journalArticlepeer-review

40 Scopus citations


We study the spatio-temporal dynamics of a model of polar active fluid in two dimensions. The system exhibits a transition from an isotropic to a polarized state as a function of density. The uniform polarized state is, however, unstable above a critical value of activity. Upon increasing activity, the active fluids displays increasingly complex patterns, including traveling bands, traveling vortices and chaotic behavior. The advection arising from the particles self-propulsion and unique to polar fluids yields qualitatively new behavior as compared to that obtained in active nematic, with traveling-wave structures. We show that the nonlinear hydrodynamic equations can be mapped onto a simplified diffusion-reaction-convection model, highlighting the connection between the complex dynamics of active system and that of excitable systems.

Original languageEnglish (US)
Pages (from-to)129-139
Number of pages11
JournalSoft Matter
Issue number1
StatePublished - Jan 7 2012

ASJC Scopus subject areas

  • General Chemistry
  • Condensed Matter Physics


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