Kinematic Viscosity

Written by Jerry Ratzlaff on . Posted in Fluid Mechanics

Kinematic viscosity is the ratio of dynamic viscosity to density.

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.

\(1 St = 1 cm^2·s^{−1} = 10^{−4} m^2·s^{−1}\)

1 centistokes = 1 mm2/s

In natural gas engineering work, the kinematic viscosity is not normally used. Instead absolute viscosity is used.  


\(\nu = \frac {\mu} {\rho}\)


\(\nu\) (Greek symbol nu) = kinematic viscosity

\(\mu\) (Greek symbol mu) = dynamic viscosity

\(\rho\) (Greek symbol rho) = density