From the perspective of blood flow, blood has some unusual properties: it is a suspension of blood cells of which the red blood cells are most numerous and are both deformable (at moderate and high flow rates) and will aggregate under conditions of slow flow. Also, the cellular volume concentration is high (about 40-45%). These features cause blood to have variable viscosity, dependent on flow conditions, and cause both red blood cell sedimentation and syneresis effects under slow flow conditions (which can lead to rheological artifacts). These effects also cause unusual flow phenomena when...