# Knudsen Number Calculator

Select the quantity that you want to calculate & write the values in the below tabs and hit on the calculate button to determine the value of the selected terms.

m
m

## Formula

Knudsen Number :
Kn = λ/L

Mean Free Path :
λ = Kn*L

Representative Physical Length Scale :
L = λ/ Kn

Where,
Kn = Knudsen Number,
λ = Mean Free Path,
L = Representative Physical Length Scale.

The Knudsen Number refers to the dimensionless number. The Knudsen Number is defined as the ratio of the molecular mean free path length to a representative physical length scale. In short, the Knudsen Number refers to the ratio of the mean free path length of the molecules of a fluid to a characteristic length. It is used to describe the flow of the low density gases.

This Advanced Online Knudsen Number Calculator is used to calculate the ratio of the mean free path length of the molecules of a fluid to a characteristic length.

Example:
Calculate the Knudsen Number for the given details.
Mean Free Path (λ) = 25 m
Representative Physical Length Scale (L) = 20 m

Solution:
Apply Formula:
Kn = λ/L
Kn = 25/20
Kn = 1.25