Reorientation dynamics of microswimmers at fluid-fluid interfaces
arXiv:2202.10421 · doi:10.1103/PhysRevFluids.7.L042001
Abstract
We study the orientational and translational dynamics of spherical microswimmers trapped at fluid interfaces, in terms of the force dipole and source dipole components of their flow field. Using numerical simulations and analytical calculations, we show that the force dipole exerts a torque, orienting pushers parallel to the interface, and pullers in normal direction. The source dipole results in particle rotation only for a finite viscosity contrast between the two fluids, in agreement with previous studies. The superposition of these two contributions leads to an rotational dynamics with a steady-state orientation that depends on the relative magnitudes of the force and source dipoles. In the general case, swimmers with weak force dipoles and strong pullers are observed to align perpendicular to the interface and become stationary, while strong pushers have a finite inclination angle towards the lower viscosity fluid and swim along the interface.
References in corpus (13)
- The hydrodynamics of swimming microorganisms
- Swimming in circles: Motion of bacteria near solid boundaries
- Inertial effects in three dimensional spinodal decomposition of a symmetric binary fluid mixture: A lattice Boltzmann study
- Dynamics of swimming bacteria at complex interfaces
- Soft swimming: Exploiting deformable interfaces for low-Reynolds number locomotion
- Viscotaxis: microswimmer navigation in viscosity gradients
- Active particles in viscosity gradients
- Hydrodynamic interaction of a self-propelling particle with a wall: Comparison between an active Janus particle and a squirmer model
- Thermally driven Marangoni surfers
- A two-dimensional model of low-Reynolds number swimming beneath a free surface
- Axisymmetric Squirmers in Stokes Fluid with Nonuniform Viscosity
- Dynamics of a helical swimmer crossing viscosity gradients
- Driven and active colloids at fluid interfaces