A consistent description of a shear ow, the accompanied viscous heating, an
d the associated entropy balance is given in the framework of a determinist
ic dynamical system, where a multibaker dynamics drives two fields: the vel
ocity and the temperature distributions. In an appropriate macroscopic limi
t their transport equations go over into the Navier-Stokes and the heat con
duction equation of viscous flows. The inclusion of an artificial heat sink
can stabilize steady states with constant temperatures. It mimics a thermo
stating algorithm used in non-equilibrium molecular-dynamics simulations.