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arXiv · 1207.5349

Spontaneous Circulation of Confined Active Suspensions

Francis G. Woodhouse·Raymond E. Goldstein
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Abstract

Many active fluid systems encountered in biology are set in total geometric confinement. Cytoplasmic streaming in plant cells is a prominent and ubiquitous example, in which cargo-carrying molecular motors move along polymer filaments and generate coherent cell-scale flow. When filaments are not fixed to the cell periphery, a situation found both in vivo and in vitro, we observe that the basic dynamics of streaming are closely related to those of a non-motile stresslet suspension. Under this model, it is demonstrated that confinement makes possible a stable circulating state; a linear stability analysis reveals an activity threshold for spontaneous auto-circulation. Numerical analysis of the long-time behavior reveals a phenomenon akin to defect separation in nematic liquid crystals, and a high-activity bifurcation to an oscillatory regime.

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Francis G. Woodhouse, Raymond E. Goldstein. 2013-01-09. Spontaneous Circulation of Confined Active Suspensions. https://doi.org/10.1103/physrevlett.109.168105

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