Nanoparticle dispersion in porous media: Effects of array geometry and flow orientation

We investigate the effects of array geometry and flow orientation on transport of finite-sized particles in ordered arrays using Stokesian dynamics simulations. We find that quiescent diffusion is independent of array geometry over the range of volume fraction of the nanoposts examined. Longitudinal dispersion under flow depends on the direction of incident flow relative to the array lattice vectors. Taylor-Aris behavior is recovered for flow along the lattice directions, whereas a nonmonotonic dependence of the dispersion coefficient on the Peclet number is obtained for flow orientations slightly perturbed from certain lattice vectors, owing to a competition between directional locking and spatial velocity variations.

Automated summary

Through simulations, we found that quiescent diffusion in ordered arrays is independent of array geometry, while longitudinal dispersion under flow depends on the direction of incident flow relative to the array lattice vectors. Flow along the lattice directions exhibits Taylor-Aris behavior, while flow orientations slightly perturbed from certain lattice vectors show a nonmonotonic dependence of the dispersion coefficient on the Peclet number, due to competition between directional locking and spatial velocity variations.