On the Reological Properties of Human Blood

Abstract

A reasonably robust procedure is presented to evaluate each of the parameters of four non-Newtonian constitutive relationships for human blood, namely Cross, Carreau-Yasuda and modifications to Ostwald-de Waele and Sisko fluids. For each of the rheological models presented herein, a multidimensional optimization routine is used to find salient constitutive parameters from a compilation of digitized experimental data evident in the literature. It is shown for three of the models that, to conserve structural identification, the so-called low shear viscosity term can be set as it has little physiological relevance. The method presented herein is shown to minimize the square of the errors between the four suggested constitutive relationships and empirical data. It is shown that, for the data set investigated here, parameters which had previously been assumed to be fluid properties exhibit different values depending on the constitutive relationship selected.