Viscosimetry

Viscosimetry 

a branch of physics devoted to methods of measuring viscosity. The reasons for the substantial variety of methods and designs of equipment for measuring viscosity (viscosimeters) are both the wide range of values of viscosity (from 10^-5 nanosec/m² for gases to 10¹² nanosec/m² for a number of polymers) and the necessity for measuring it at low or high temperatures and pressures (for example, compressed gases, molten metals, and water vapor under high pressures).

The three most widely used methods of measuring the viscosity of liquids and gases are the capillary method, the falling sphere method, and the method of coaxial cylinders (rotation method). They are based respectively upon Poiseuille’s law, Stokes’ law, and the law of the flow of a liquid between coaxial cylinders. Viscosity is also determined according to the extinguishing of periodic oscillations of a plate placed in the medium to be investigated.

There is a special group of methods of viscosity measurement which use small volumes of the medium (micro-viscosity). These methods are based on the observation of Brownian motion, mobility of ions, and particle diffusion.

REFERENCES

Barr, G. Viskozimetriia. Leningrad-Moscow, 1938. (Translated from English.)
Targ, S. M. Osnovye zadachi teorii laminarnykh techenii. Moscow, 1951.
Fuks, G. I. Viazkost’ i plastichnost’ nefteproduktov. Moscow, 1951.
Golubev, I. F. Viazkost’ gazov i gazovykh smesei. Moscow, 1959.