Dear peter i know about the Knudsen number K n = ? / L, where ? is the mean free path and L is the characteristic length.
But i do not know how to calculate it.
The pressure is atmospheric fluid has viscosity 0.45 and density 1220
The gap between two cylinder is 5 micrometer. And the fluid has height of 100 micrometer from inlet. And semi circle diamter is 5.40 mm and big circle diamteter is 12 mm.
Actually i just want to check the flow in microcavities and some backflow(fluid accumilation or fluid backflow).
Can you please explain how to find the knudsen no. Actually i know about knudsen number but for this problem how to calculate this.