# Knudsen Number

Knudsen Number is a dimensionless number defined as the ratio of the molecular mean free path length to a representative physical length scale.

## FORMULA

\(Kn = \frac{ \lambda }{ l }\)

Where:

\(Kn\) = Knudsen Number

\( \lambda \) = mean free path

\( l\) = length

Solve for:

\(\lambda = Knl \)

\(l = \frac{ \lambda }{ Kn }\)