  Enceladus is characterised by a south polar hot spot associated with a large
outflow of heat, the source of which remains unclear. We compute the viscous
dissipation resulting from tidal and libration forcing in the moon's subsurface
ocean using the linearised Navier-Stokes equation in a 3-dimensional spherical
model. We conclude that libration is the dominant cause of dissipation at the
linear order, providing up to about 0.001 GW of heat to the ocean, which
remains insufficient to explain the (about) 10 GW observed by Cassini. We also
illustrate how resonances with inertial modes can significantly augment the
dissipation. Our work is an extension to Rovira-Navarro et al. [2019] to
include the effects of libration. The model developed here is readily
applicable to the study of other moons and planets.
