Entrance Length in Pipe Flow: Summary

The answers to the ConcepTests are given below and will open in a separate window. 
Key points from this module:
  • An entrance length in pipes is where viscous forces create a boundary layer.
  • The equation for entrance length for laminar flow differs from that for turbulent flow.
  • The velocity doesn’t change with respect to the length of the pipe in fully-developed flow.
From studying this module, you should now be able to:
  • Determine if flow in a pipe is laminar or turbulent.
  • Calculate the entrance length for both laminar and turbulent flow.
  • Determine where a flow becomes fully-developed.


Prepared by Janet deGrazia, Department of Chemical and Biological Engineering, University of Colorado Boulder