Entrance Length in Pipe Flow: Example Problem

Try to solve this problem before watching the solution in the screencast.

Example Problem 1

Water enters a 4-in. diameter piping system from a reservoir with a volumetric flow rate of 50 gal/min. Determine whether the flow is laminar or turbulent if during the winter the water temperature is 45°F and if it reaches 65°F during the summer. What is the length of pipe necessary to reach fully developed flow?