Non-identifiability of parameters for a class of shear-thinning rheological models, with implications for haematological fluid dynamics

摘要: Choosing a suitable model and determining its associated parameters from fitting to experimental data is fundamental for many problems in biomechanics. Models of shear-thinning complex fluids, dating the work Bird, Carreau, Cross Yasuda, have been applied highly-cited computational studies hemodynamics several decades. In this manuscript we revisit these models, first highlight degree uncertainty naming conventions literature, but more importantly address problem inferring by rheology experiments. By refitting published data, also simulation, find large, flat regions likelihood surfaces that yield families parameter sets which fit equally well. Despite having almost indistinguishable fits varying can predict very different flow profiles, as such cannot be used draw conclusions about physical properties zero-shear viscosity or relaxation time fluid, indeed behaviours. We verify features are not consequence through simulations; sampling points rheological models adding small amount noise create synthetic set reveals identifiability intrinsic models.