Velocity Needed to Purge and Air Lock

[Ballintoy]

I am trying to develop a general relationship for the velocity needed to purge an air bubble from a water pipe with multiple high spots. Any suggestions?

 

[semo]

The Water Pollution Control Federation Manual of Practice No. FD-4 "Design of Wastewater and Stormwater Pumping Stations" states "A minimum velocity of 1.2 m/s (4 ft/sec) is required in the pipeline to shear the bubble and keep it moving downgrade."

Hope this helps.