  A port-Hamiltonian model for compressible Newtonian fluid dynamics is
presented in entirely coordinate-independent geometric fashion. This is
achieved by use of tensor-valued differential forms that allow to describe
describe the interconnection of the power preserving structure which underlies
the motion of perfect fluids to a dissipative port which encodes Newtonian
constitutive relations of shear and bulk stresses. The relevant diffusion and
the boundary terms characterizing the Navier-Stokes equations on a general
Riemannian manifold arise naturally from the proposed construction.
