The hydrodynamics of slender swimmers near deformable interfaces
arXiv:2112.04409 · doi:10.1103/PhysRevFluids.7.054001
Abstract
We study the coupled hydrodynamics between a motile slender microswimmer and a deformable interface that separates two Newtonian fluid regions. From the disturbance field generated by the swimming motion, we quantitatively characterize the interface deformation and the manner in which the coupling modifies the microswimmer translation itself. We treat the role of the swimmer type (pushers and pullers), size and model an interface that can deform due to both surface tension and bending elasticity. Our analysis reveals a strong dependence of the hydrodynamics on the swimmer orientation and position. Given the viscosities of the two fluid media, the interface properties and the swimmer type, a swimmer can either migrate towards or away from the interface depending on its configurations. When the swimmer is oriented parallel to the interface, a pusher-type swimmer is repelled from the interface at short times if it is swimming in the more viscous fluid. At long times however, pushers are always attracted to the interface, and pullers are always repelled from it. On the other hand, swimmers oriented orthogonal to the interface exhibit a migration pattern opposite to the parallel swimmers. In consequence, a host of complex migration trajectories emerge for swimmers arbitrarily oriented to the interface. We find that confining a swimmer between a rigid boundary and a deformable interface results in regimes of attraction towards both surfaces depending on the swimmer location in the channel, irrespective viscosity ratio. The differing migration patterns are most prominent in a region of order the swimmer size from the interface, where the slender swimmer model yields a better approximation to the coupled hydrodynamics.
References in corpus (29)
- Active Particles in Complex and Crowded Environments
- The hydrodynamics of swimming microorganisms
- Physics of Microswimmers - Single Particle Motion and Collective Behavior
- Hydrodynamic attraction of swimming microorganisms by surfaces
- Hydrodynamics of self-propulsion near a boundary: predictions and accuracy of far-field approximations
- Bacterial hydrodynamics
- Fluid Flows Created by Swimming Bacteria Drive Self-Organization in Confined Suspensions
- Elastocapillarity: Surface Tension and the Mechanics of Soft Solids
- Directed collective motion of bacteria under channel confinement
- Spontaneous Circulation of Confined Active Suspensions
- Transport of a dilute active suspension in pressure-driven channel flow
- Soft swimming: Exploiting deformable interfaces for low-Reynolds number locomotion
- The force on a body in active matter
- Upstream swimming in microbiological flows
- The role of correlations in the collective behaviour of microswimmer suspensions
- Particle diffusion in active fluids is non-monotonic in size
- On the distribution and swim pressure of run-and-tumble particles in confinement
- Motility-sorting of self-propelled particles in micro-channels
- Enhanced motility of a microswimmer in rigid and elastic confinement
- Long-lived anomalous thermal diffusion induced by elastic cell membranes on nearby particles
- Hindered mobility of a particle near a soft interface
- Crawling beneath the free surface: Water snail locomotion
- A two-sphere model for bacteria swimming near solid surfaces
- A reciprocal theorem for the prediction of the normal force induced on a particle translating parallel to an elastic membrane
- Swimming near Deformable Membranes at Low Reynolds Number
- Frequency-dependent higher-order Stokes singularities near a planar elastic boundary: implications for the hydrodynamics of an active microswimmer near an elastic interface
- Fluctuation Spectra and Force Generation in Non-equilibrium Systems
- Enhanced velocity fluctuations in interacting swimmer suspensions
- A note on forces exerted by a Stokeslet on confining boundaries