Kinematic viscosity is commonly referred to by the Greek Symbol Nu, and is defined as follows:
where
is the (dynamic) viscosity
is the density.
In the SI system the units are (m2·s−1). The US Customary Measurement for kinematic viscosity is stokes (abbreviated S or St), named after George Gabriel Stokes. It is sometimes expressed in terms of centistokes (cS or cSt). In U.S. usage, stoke is sometimes used as the singular form.
1 stokes = 100 centistokes = 1 cm2·s−1 = 0.0001 m2·s−1.
1 centistokes = 1 mm2/s
In natural gas engineering work, the kinematic viscosity is not normally used. Instead Absolute Viscosity is used.
