  Superfluid condensates are known to occur in contexts ranging from laboratory
liquid helium to neutron stars, and are also likely to occur in cosmological
phenomena such as axion fields. In the zero temperature limit, such condensates
are describable at a mesoscopic level by irrotational configurations of simple
relativistic perfect fluid models. The general mechanical properties of such
models are presented here in an introductory review giving special attention to
the dynamics of vorticity flux 2-surfaces and the action principles governing
both individual flow trajetories and the evolution of the system as a whole.
Macroscopic rotation of such a condensate requires the presence of a lattice of
quantised vortex defects, whose averaged tension violates perfect fluid
isotropy. It is shown that for any equation of state (relating the mass density
$\rho$ to the pressure $P$) the mesoscopic perfect fluid model can be extended
in a uniquely simple and natural manner to a corresponding macroscopic model
(in a conformally covariant category) that represents the effects of the vortex
fibration anisotropy. The limiting case of an individual vortex defect is shown
to be describable by a (``global'') string type model with a variable tension
${\cal T}$ (obtained as a function of the background fluid density) whose
``vorton'' (i.e. closed loop equilibrium) states are derived as an exercise.
