  The aim of this paper is to present a modeling for the rheological behavior
of simple liquids as a function of the amplitude of the imposed shear stress or
strain. The elastic mode theory (Ref. 6) is first generalized to take into
account the fact that during a flow experiment, mechanical energy is injected
in a system initially at thermodynamic equilibrium. This generalized theory can
be seen as a particular aspect of the general problem of perturbation by the
measurement, associated with that of the coupling between fluctuation and
dissipation. This generalization leads to a "finitary" character of the model.
It is then combined with the inertial mode theory (Ref. 7). The formalism thus
obtained allows to model the rheological behavior of liquids over a wide range
of velocity gradients, including the intermediate narrow range corresponding to
the Newtonian regime. As experimental tests, viscosity measurements with two
kinds of moving rotor rheometers were performed. Only data obtained with liquid
water at room temperature are presented and quantitatively analyzed here. It is
also shown that liquid n-octane exhibits the same qualitative behaviors as
those of liquid water. In the appendices, connection of this theory with
quantum mechanics and turbulence phenomena are discussed, and the notion of
viscous mass is introduced.
