Meso-swimmer suspensions: immersed boundary simulations of hydrodynamic interactions between worm-like swimmers

Hydrodynamic interaction between swimming organisms has long been a topic of interest in fluid-structure interaction. Especially, collective motion of swimming organisms such as bacteria, spermatozoa, and worms has recently received a great deal of attention from researchers in many disciplines, including biology, mathematics, engineering, food science, etc. To fully understand the collective behaviour of swimmers in dilute suspensions, near-field hydrodynamics need to be investigated. In an inertial regime, where Reynolds numbers range roughly from 0.1 to 100, and both advection and diffusion effects are present, the flow dynamics are described by the Navier-Stokes equations. We employed the immersed boundary method to couple the fluid and swimming worms (which we will refer to as meso-swimmers) in a system of integro-differential equations. We numerically examined individual, pairwise, and collective interactions of worms where phenomena such as synchronization, attraction as well as aggregation in dilute suspensions of swimmers are observed.