Knudsen Number

Knudsen number, abbreviated as Kn, a dimensionless number, is used in fluid dynamics to determine what type of analysis should be used to model an object moving through a fluid.  It is defined as the ratio of the molecular mean free path length to a representative physical length scale.  This calculation determines the Knudsen number, the length or the lambda value based on your inputs.

 

Knudsen number calculator

Knudsen Number formula \(\large{ Kn = \frac{ \lambda }{ l } }\)    Where:  Units English Metric \(\large{ Kn }\) = Knudsen number \(\large{dimensionless}\) \(\large{ l }\) = length \(\large{in}\) \(\large{mm}\) \(\large{ \lambda }\) (Greek symbol lambda) = mean free path \(\large{in}\) \(\large{mm}\) Solve For: \(\large{ l = \frac{ \lambda }{ Kn } }\)    \(\large{ \lambda = Kn \; l  }\)