The usual form of Poiseuille's equation for the flow of a viscous liquid through a capillary tube is not difficult to deduce mathematically upon the basis of certain assumptions. These are: (1) that there is no appreciable slip at the inner surface of the capillary, that is, that at this distance from the axis the speed of flow is zero; (2) that the flow is steady, so that inertia plays no part in it; (3) that the capillary is perfectly cylindrical and perfectly straight, and (4) that there are no end effects, such as surface tension and eddies.
Proceedings of the Iowa Academy of Science
©1927 Iowa Academy of Science, Inc.
Weld, LeRoy D.
"Test of a U-Tube Capillary Viscometer,"
Proceedings of the Iowa Academy of Science, 34(1), 263-265.
Available at: https://scholarworks.uni.edu/pias/vol34/iss1/66