  The transport of deformable particles through porous media underlies a wealth
of applications ranging from filtration to oil recovery to the transport and
spreading of biological agents. Using direct numerical simulations, we analyze
the dynamics of semiflexible polymers under the influence of an imposed flow in
a structured two-dimensional lattice serving as an idealization of a porous
medium. This problem has received much attention in the limit of reptation and
for long-chain polymer molecules such as DNA that are transported through
micropost arrays for electrophoretic chromatographic separation. In contrast to
long entropic molecules, the dynamics of elastic polymers results from a
combination of scattering with the obstacles and flow-induced buckling
instabilities. We identify three dominant modes of transport that involve
trapping, gliding and vaulting of the polymers around the obstacles, and we
reveal their essential features using tools from dynamical systems theory. The
interplay of these scattering dynamics with transport and deformations in the
imposed flow results in the long-time asymptotic dispersion of the center of
mass, which we quantify in terms of a hydrodynamic dispersion tensor. We then
discuss a simple yet efficient chromatographic device that exploits the
competition between different modes of transport to sort filaments in a dilute
suspension according to their lengths.
