RHEOLOGICAL PROPERTIES OF BIOLOGICAL FLOW SYSTEMS

This paper describes briefly some of the non-Newtonian flow phenomena encountered in the flow of biological fluids. Primary emphasis is put on the interaction of shear-dependent and scale-dependent effects which occurs for slow flow in small tubes. Non-Newtonian fluid models are discussed and the experimental data for the pressure drop and velocity distribution of blood flow in small tubes are reviewed. A transformation parameter is described which stretches the radial dimension in such a way that the velocity distribution gives a direct indication of the viscosity variation across the flow. Simple analytic models are described which reproduce many features of the experiments.