Pipe Flow: Entrance Region & Entrance Length

[@LearnChemE]

This screencast has been reviewed by faculty from other academic institutions.

[@mmtzka]

Is the inviscid core length equal to the entrance length for all conditions, some sources say that the entrance length is longer than the inviscid core length?

[@andreithesea]

Is there a way to figure out whether the fluid flow is laminar or turbulent just from a given entrance length? I recently encounter a problem during my exam on this, and up until now I'm unable to answer it. The given for the problem was: SG = 1.150, viscosity = 0.950 cP, mass flow rate =1.746kg/s, entrance length = 221mm.

[@shizojoshi]

could you please tell me that why roughness ratio (E/D) (in moody's chart) matters only in turbulent flow? Thank you.

[@LearnChemE]

Its been found through experimental data that the pressure drop in laminar flow is independent of surface roughness. Under laminar flow the viscous effects are significant across the entire pipe so there is no presence of a thin viscous layer that would be dependent on surface roughness. The surface effects are negligible.

[@shizojoshi]

thankyou.

[@fatimaaa3600]

thanks a lot