In this example, the automatic method will be used to perform fitting for a Carreau-Yasuda fluid with experimental data curves of shear viscosity vs. shear rate at four different temperatures. The Carreau-Yasuda law has been chosen for its plateau zone at low shear rates and its controllable transition zone.

For temperature dependence, the Arrhenius shear-stress law has been chosen for its vertical and horizontal shifts. is fixed at 240°C; it is recommended that you set it to one of the temperatures at which experimental data were measured, close to the average of those temperatures. Since the experimental data are based on degrees Celsius, is set to , as required for proper scaling.