Toward a constitutive equation for blood

Abstract

A non-linear viscoelastic constitutive equation is proposed as a model for blood. The model allows normal stress effects which are observed to occur in viscoelastic fluids but not included in most rheological models for blood. The shear thinning nature of the model is illustrated by its application in circular Couette flow. A two-dimensional channel flow problem is included to show that a blunted profile can be predicted. Finally, application to the Couette flow viscometer problem shows that a stress overshoot is predicted by the viscoelastic model proposed without the need for a postulate of a cell-free layer.