  In this paper we consider the problem of obtaining a general port-Hamiltonian
formulation of Newtonian fluids. We propose the port-Hamiltonian models to
describe the energy flux of rotational three-dimensional isentropic and
non-isentropic fluids, whose boundary flows and efforts can be used for control
purposes or for power-preserving interconnection with other physical systems.
In case of two-dimensional flows, we include the considerations about the
operators associated with fluid vorticity, preserving the port-Hamiltonian
structure of the models proposed.
