  The temporal behaviors of non-Newtonian/Newtonian two-phase flows are closely
tied to flow pattern formation mechanisms, influenced significantly by the
non-Newtonian index, and exhibiting nonlinear rheological characteristics. The
rheological model parameters are model-dependent, resulting in poor
predictability of their spatio-temporal characteristics. This limitation
hinders the development of a unified analytical approach and consistent
results, confining researches to case-by-case studies. In this study, sets of
digital microfluidics experiments, along with continuous-discrete
phase-interchanging schemes, yielded 72 datasets under various non-Newtonian
fluid solution configurations, micro-channel structures, and multiple
Carreau-related models. Among these datasets, we identified consistent temporal
behaviors featuring non-Newtonian flow patterns in digital microfluidics. In
the context of significant model dependency and widespread uncertainty in model
parameters for non-Newtonian fluid characterization, this study demonstrates
that the consistent representation of the non-Newtonian behavior exit, and may
be essentially independent of specific data or models. Which finding holds
positive implications for understanding the flow behavior and morphology of
non-Newtonian fluids.
