Bailout Embeddings and Neutrally Buoyant Particles in Three-Dimensional   Flows
  We use the bailout embeddings of three-dimensional volume-preserving maps to study qualitatively the dy- namics of small spherical neutrally buoyant impurities suspended in a time-periodic incompressible fluid flow. The accumulation of impurities in tubular vortical structures, the detachment of particles from fluid trajectories near hyperbolic invariant lines, and the formation of nontrivial three-dimensional structures in the distribution of particles are predicted. 
J.H.E. Cartwright, M.O. Magnasco, O. Piro and I. tuval