Types of Flow

Types of flow
turbulent flow
laminar flow
transitional flow
molecular flow
Leak Rate (mbar · l/s)
〉 10-2
10-1 - 10-6
10-4 - 10-7
〈 10-7

(Source: Leakage Testing Handbook, Prepared for Liquid Propulsion Section, Jet Propulsion Laboratory, National Aeronautics and Space Administration, Pasadena, California)

In most cases in leak detection technology it is not possible to calculate accurately the kind of flow - it must be estimated. Of course there are formulae for calculation of the conductance for different pipes etc. All these formulae contain geometry factors (length, diameter etc.) but with leaks in normal practice, these factors are unknown.