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arXiv · 1808.07805

Concentration banding instability of a sheared bacterial suspension

Laxminarsimharao V·Piyush Garg·Ganesh Subramanian
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Abstract

We demonstrate a novel shear-induced mechanism for growth of concentration fluctuations in a bacterial suspension. Using a linear stability analysis, a homogeneously sheared suspension is shown to support exponentially growing layering perturbations in the shear-rate and bacterial concentration. Non-linear simulations show that the instability eventually leads to gradient-banded velocity profiles, with a local depletion of bacteria at the interface between the bands. Our results show that long-ranged hydrodynamic interactions are sufficient to explain recent observations of shear-bands in bacterial suspensions.

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Laxminarsimharao V, Piyush Garg, Ganesh Subramanian. 2018-08-23. Concentration banding instability of a sheared bacterial suspension. https://arxiv.org/abs/1808.07805

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