Hydrodynamic fluctuations and instabilities in ordered suspensions of self-propelled particles
Abstract
We construct the hydrodynamic equations for {\em suspensions} of self-propelled particles (SPPs) with spontaneous orientational order, and make a number of striking, testable predictions:(i) SPP suspensions with the symmetry of a true {\em nematic} are {\em always} absolutely unstable at long wavelengths.(ii) SPP suspensions with {\em polar}, i.e., head-tail {\em asymmetric}, order support novel propagating modes at long wavelengths, coupling orientation, flow, and concentration. (iii) In a wavenumber regime accessible only in low Reynolds number systems such as bacteria, polar-ordered suspensions are invariably convectively unstable.(iv) The variance in the number N of particles, divided by the mean <N>, diverges as in polar-ordered SPP suspensions.
Cite
@article{arxiv.cond-mat/0108301,
title = {Hydrodynamic fluctuations and instabilities in ordered suspensions of self-propelled particles},
author = {R. Aditi Simha and Sriram Ramaswamy},
journal= {arXiv preprint arXiv:cond-mat/0108301},
year = {2009}
}
Comments
submitted to Phys Rev Lett