  We study the collective modes of the confined unitary Fermi gas under
anisotropic harmonic confinement as a function of the number of atoms. We use
the equations of extended superfluid hydrodynamics, which take into account a
dispersive von Weizsacker-like term in the equaton of state. We also discuss
the inclusion of a backflow term in the extended superfluid Lagrangian and the
effects of this anomalous term on sound waves and Beliaev damping of phonons.
