Hydrodynamic interactions dominate the structure of active swimmers' pair distribution functions
arXiv:1812.06687 · doi:10.1063/1.5085755
Abstract
Microswimmers often exhibit surprising patterns due to the nonequilibrium nature of their dynamics. Collectively, suspensions of microswimmers appear as a liquid whose properties set it apart from its passive counterpart. To understand the impact of hydrodynamic interactions on the basic statistical features of a microswimmer's liquid, we investigate its structure by means of the pair distribution function. We perform particle-based simulations of microswimmers that include steric effects, shape anisotropy, and hydrodynamic interactions. We find that hydrodynamic interactions considerably alter the orientation-dependent pair distribution function compared to purely excluded-volume models like active Brownian particles, and generally decrease the structure of the liquid. Depletion regions are dominant at lower filling fractions, while at larger filling fraction the microswimmer liquid develops a stronger first shell of neighbors in specific directions, while losing structure at larger distances. Our work is a first step towards a statistico-mechanical treatment of the structure of microswimmer suspensions.
6 pages, 7 figures
References in corpus (14)
- Meso-scale turbulence in living fluids
- Hydrodynamic attraction of swimming microorganisms by surfaces
- Fluid dynamics and noise in bacterial cell-cell and cell-surface scattering
- Direct measurement of the flow field around swimming microorganisms
- Effective Interactions in Active Brownian Suspensions
- Multi-Particle Collision Dynamics -- a Particle-Based Mesoscale Simulation Approach to the Hydrodynamics of Complex Fluids
- Particle-Based Mesoscale Hydrodynamic Techniques
- Orientational order in concentrated suspensions of spherical microswimmers
- Relevance of angular momentum conservation in mesoscale hydrodynamics simulations
- Spontaneous aggregation and global polar ordering in squirmer suspensions
- Lane formation in a system of dipolar microswimmers
- Active Brownian Particles Escaping a Channel in Single File
- Static Structure of Active Brownian Hard Disks
- Three-body correlations and conditional forces in suspensions of active hard disks