2019/09/05 by Matteo Borgnino, M. Borgnino, K. Gustavsson +5 · 42 citations
Engineering · Physics and Astronomy · #Advection #Chaotic #Chaotic mixing #Classical mechanics #Flow (mathematics) #Geology #Geometry #Mechanics #Micro and Nano Robotics #Microfluidic and Bio-sensing Technologies #Particle (ecology) #Particle Dynamics in Fluid Flows #Perturbation (astronomy) #Perturbation theory (quantum mechanics) #Physics #Quantum mechanics #Rod #Rotational symmetry #Statistical physics #Symmetry (geometry) #Symmetry breaking #Turbulence #cond-mat.soft #physics.flu-dyn
paper · pdf · doi:10.1103/physrevlett.123.138003
published in Physical Review Letters 123(13), 138003 (American Physical Society) · 5 pages, 3 figures, Supplements in Ancillary directory, accepted in Physical Review Letters
arxiv created 2019/09/05 · openalex publication_date 2019/09/27 · arxiv updated 2019/10/02 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
We study the orientation statistics of spheroidal, axisymmetric microswimmers, with shapes ranging from disks to rods, swimming in chaotic, moderately turbulent flows. Numerical simulations show that rodlike active particles preferentially align with the flow velocity. To explain the underlying mechanism, we solve a statistical model via the perturbation theory. We show that such an alignment is caused by correlations of fluid velocity and its gradients along particle paths combined with fore-aft symmetry breaking due to both swimming and particle nonsphericity. Remarkably, the discovered alignment is found to be a robust kinematical effect, independent of the underlying flow evolution. We discuss its possible relevance for aquatic ecology.