Rheology and velocity predictions of the fluids. a Viscosity trends in shear flow predicted by the constitutive equations used in this work. The model parameters are reported in Table 1. The inset shows the trend of the first normal stress difference coefficient for the Giesekus fluid. b Velocity profiles obtained in a wide-slit channel for the same constitutive equations as in panel (a). The velocity is normalized by its average value whereas the position along the gap is normalized by the channel height.