Large scale modeling of blood flow in the capillaries 1

Abstract

A large scale fluid-mechanical model has been used to study certain aspects of the flow of blood in capillaries. In the model, large, rigid, neutrally buoyant disc-like cells (discoids) are transported by a viscous fluid through a 1 cm glass tube. Observations of the orientation of the model cells lead to the conclusion that both cross-sectional profile and large cell-to-tube diameter ratio are important factors in the normal (“piston-like”) stability of discoids in low Reynolds number tube flow. Pressure drop measurements show that size (i.e., diameter and thickness), spacing and orientation of discoids are factors which determine the additional pressure drop (in excess of the Poiseuille pressure drop) associated with the cell motion. For discoids in the normal orientation, the additional pressure drop is most sensitive to the diameter of the discoid. Pressure drops calculated from the experimental data are compared with pressure-drop measurements in vivo. Finally, a possible mechanism for non-linear pressure-flow characteristics for blood flow in capillaries is suggested.