Micro-swimmers in Brinkman flow: coupled dynamics and motion near surfaces

Micro-swimmer dynamics in heterogeneous media is receiving increased interest in fluid dynamics and biological physics due to the pervasiveness of microorganisms in complex environments. A model for porous media or media with impurities is the Brinkman fluid which accounts for a sparse matrix of stationary sphere obstacles via a linear resistance term added to the momentum equation. We present theoretical derivations and numerical simulations of the coupled motion of dumb-bell micro-swimmers in Brinkman flow as well as their dynamics near no-slip and no-stress planes. The results provide new analytical tools for understanding locomotion in complex fluids and offer new insights on the collective behavior of active suspensions within porous or structured environments.