A parameter defined such that

(1)

Written explicitly,

(2)

where l is the length scale and u is the velocity scale. In cgs, has units of g cm^-1 s^-1, or poise. 1 poise = 1/10 Pa s. Dynamic viscosity is related to kinematic viscosity by

(3)

where is the density.

Kinematic Viscosity, Viscosity