Fluids with suspended micro-structure (complex fluids) arise commonly in micro- and bio-fluidics, and can have fascinating and novel dynamical behaviors.
I will discuss some interesting examples of this, but will concentrate on my recent work on active suspensions, motivated by recent experiments on bacterial baths.
Using large-scale particle-based simulations of hydrodynamically interacting swimmers, as well as a recently developed kinetic theory, I will investigate how hydrodynamically mediated interactions lead to large-scale instability, coherent structures, and mixing.