How Does Knudsen Flow Differ from Other Types of Flow?
In general, gas flow can be classified into three regimes: viscous flow, molecular flow, and Knudsen flow. Viscous flow occurs when the mean free path is much smaller than the dimensions of the system, leading to frequent collisions between molecules. Molecular flow, on the other hand, occurs when the mean free path is much larger, making collisions rare. Knudsen flow is an intermediate regime where the mean free path is similar to the characteristic dimensions of the system, leading to a combination of molecule-wall and molecule-molecule interactions.
