Knudsen number

The Knudsen number (Kn) is the ratio of the molecular mean free path length to a representative physical length scale.

It is defined as:

<math>Kn = \frac {\lambda}{L} = \frac {k_B T}{\sqrt{2}\pi\sigma^2 P L} <math>

where

• T, temperature (K)
• k_B, Boltzmann's constant
• P, total pressure (Pa)

See also

• Fluid dynamics
• Mach number
• Reynolds number

fr:Nombre de Knudsen nl:Getal van Knudsen