Swimming bacteria in Poiseuille flow: The quest for active Bretherton-Jeffery trajectories

Abstract

Using a 3D Lagrangian tracking technique, we determine experimentally the trajectories of non-tumbling E. coli mutants swimming in a Poiseuille flow. We identify a typology of trajectories in agreement with a kinematic "active Bretherton-Jeffery" model, featuring an axisymmetric self-propelled ellipsoid. In particular, we recover the "swinging" and "shear tumbling" kinematics predicted theoretically by Zöttl et al. [1]. Moreover using this model, we derive analytically new features such as quasi-planar piece-wise trajectories, associated with the high aspect ratio of the bacteria, as well as the existence of a drift angle around which bacteria perform closed cyclic trajectories. However, the agreement between the model predictions and the experimental results remains local in time, due to the presence of Brownian rotational noise. p-1 arXiv:1903.02995v2 [physics.flu-dyn]

Chirality-induced bacterial rheotaxis in bulk shear flows

“…For motile microorganisms, orientation dynamics, mainly governed by Jeffery dynamics ( 9 ), directly translate into swimming directions and drift velocities become of the order of swimming velocities. In shear flow, microswimmers crossing streamlines lead to new families of “active Jeffery orbits.” In Poiseuille flow, “swinging” and “shear-tumbling” trajectories ( 19 , 20 ) were identified theoretically and numerically, and their existence was recently confirmed experimentally for motile Escherichia coli bacteria ( 21 ). Moreover, in Poiseuille flow, kinetic theory ( 22 ) predicts that the interplay between stochastic reorientation, active swimming, and the varying local shear rate leads to preferred upstream and downstream swimming.…”

“…The effective aspect ratio  is determined from the deviation from the linear regime toward the saturation of the rheotactic velocity at high shear rates, with the results not being very sensitive to the value of the parameter . Here, we use  = 5, in agreement with typical experimental values (21). These values for  and  are used for all further comparison between experiments and simulations.…”

Upstream swimming and Taylor dispersion of active Brownian particles

“…Various theoretical models have been proposed to explain the swimming dynamics of microorganisms in flow, many of which include the effect of fluid shear, body shape asymmetry, flagellar chirality, steric and/or hydrodynamic interaction with the wall, and so forth [24,[32][33][34][35][36][37][38]. These models are able to produce, at least qualitatively, upstream motion similar to those observed in experiments.…”

Alignment of Nonspherical Active Particles in Chaotic Flows

“…For Λ > 0, Eqs. (1-2) represent a minimal model for a smooth swimming (not tumbling) bacterium [15,16]. Rotational diffusivity in Eq.…”