On the polar fluid as a model for blood flow in tubes

Abstract

It is argued that the theory of polar fluids does not adequately model blood flow in the microcirculation. The principal argument against the use of the theory is that, on one hand, most experimental evidence shows that a significant feature of blood flow in tubes of this size (i.e. 30–300 μm) is that local hematocrit varies with radial position in the tube, while on the other hand, polar fluid theory contains no field variable one can associate with, or use to determine, the variation of local hematocrit with radial position. A corroborative argument is that polar fluid theory does not predict a reduction in apparent viscosity in flow through tubes as tube diameter decreases while such a phenomenon is well known for blood.