Fåhræus–Lindqvist effect

[2] Shortly after, in 1931, it was reported independently by the Swedish scientists Robin Fåhræus and Torsten Lindqvist, after whom the effect is commonly named.

Robert (Robin) Sanno Fåhræus was a Swedish pathologist and hematologist, born on October 15, 1888, in Stockholm.

Capillary diameters were less than 250 μm, and experiments were conducted at sufficiently high shear rates (≥100 1/s) so that a similar flow in a large tube would be effectively Newtonian.

will depend on the fluid being tested, the capillary diameter, and the flow rate (or pressure drop).

However, for a given fluid and a fixed pressure drop, data can be compared between capillaries of differing diameter.

[6] Because the cell-free layer is very thin (approximately 3 μm) this effect is insignificant in capillaries whose diameter is large.

This explanation, while accurate, is ultimately unsatisfying, since it fails to answer the fundamental question of why a plasma cell-free layer exists.