title: Hydrodynamic interaction of microswimmers near a wall.
abstract: The hydrodynamics of an archetypal low-Reynolds number swimmer, called "squirmer," near a wall has been numerically studied. For a single squirmer, depending on the swimming mechanism, three different modes are distinguished: (a) the squirmer escaping from the wall, (b) the squirmer swimming along the wall at a constant distance and orientation angle, and (c) the squirmer swimming near the wall in a periodic trajectory. The role of inertial effects on the near-wall motion of the squirmer is quantified. The dynamics of multiple squirmers swimming between two walls is found to be very different from a single squirmer. Near-wall accumulation of squirmers are observed. At a relatively small concentration c = 0.1, around 60-80% of the squirmers are accumulated near the walls and attraction of pushers and pullers toward the wall is stronger than neutral squirmers. Near-wall squirmers orient normal to the wall, while in the bulk region, the squirmers are mostly oriented parallel to the wall. At a high concentration c = 0.4, the percentage of the near-wall squirmers is around 40%. The orientation angle of squirmers in the bulk region is more uniformly distributed at high concentrations. In the near-wall region, pullers repel each other, while pushers are attracted to each other and form clusters.
authors.affiliation: Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana 46556.
authors.forename: Gao-Jin
authors.initials: GJ
authors.lastname: Li
authors.affiliation: Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 and School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907.
authors.forename: Arezoo M
authors.initials: AM
authors.lastname: Ardekani
mesh_terms: D057446:Hydrodynamics; D008962:Models, Theoretical; D009038:Motion