We present explicit expressions of the helicity conservation in nematic
liquid crystal flows, for both the Ericksen-Leslie and Landau-de Gennes
theories. This is done by using a minimal coupling argument that leads to an
Euler-like equation for a modified vorticity involving both velocity and
structure fields (e.g. director and alignment tensor). This equation for the
modified vorticity shares many relevant properties with ideal fluid dynamics
and it allows for vortex filament configurations as well as point vortices in
2D. We extend all these results to particles of arbitrary shape by considering
systems with fully broken rotational symmetry.Comment: 22 pages; no figure