Dynamics of semiflexible polymers in a flow field

We present a method to investigate the dynamics of a single
semiflexible polymer, subject to anisotropic friction in a viscous
fluid. In contrast to previous approaches, we do not rely on a
discrete bead-rod model, but introduce a suitable normal mode
decomposition of a continuous space curve. By means of a
perturbation expansion for stiff filaments, we derive a closed set
of coupled Langevin equations in mode space for the nonlinear
dynamics in two dimensions, taking into account exactly the local
constraint of inextensibility. The stochastic differential
equations obtained this way are solved numerically, with parameters
adjusted to describe the motion of actin filaments. As an example,
we show results for the tumbling motion in shear flow.