  The relationship between the polymer orientation and the chaotic flow, in a
dilute solution of rigid rodlike polymers at low Reynolds number, is
investigated by means of direct numerical simulations. It is found that the
rods tend to align with the velocity field in order to minimize the friction
with the solvent fluid, while regions of rotational disorder are related to
strong vorticity gradients, and therefore to the chaotic flow. The
"turbulent-like" behavior of the system is therefore associated with the
emergence and interaction of topological defects of the mean director field,
similarly to active nematic turbulence. The analysis has been carried out in
both two and three spatial dimensions.
