Knudsen Number Calculator

Calculate the Knudsen number (Kn) to determine the statistical mechanics regime of a fluid flow. This helps decide whether to use continuum fluid dynamics (Navier-Stokes) or statistical mechanics.

Knudsen Number Calculator

e.g., 68e-9 for air at standard conditions

How to Use

  1. 1

    Enter Mean Free Path

    Input the mean free path (λ) of the particles in the fluid in meters.

  2. 2

    Enter Characteristic Length

    Input the representative physical length scale (L) in meters.

  3. 3

    Calculate

    Click calculate to view the dimensionless Knudsen number and the associated flow regime.

Frequently Asked Questions

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