  We consider a fluid model including viscoelastic and viscoplastic effects.
The state is given by the fluid velocity and an internal stress tensor that is
transported along the flow with the Zaremba-Jaumann derivative. Moreover, the
stress tensor obeys a nonlinear and nonsmooth dissipation law as well as stress
diffusion. We prove the existence of global-in-time weak solutions satisfying
an energy inequality under general Dirichlet conditions for the velocity field
and Neumann conditions for the stress tensor.
