Studies of Air Entrainment in Open-Channel Flows

The phenomenon of insuffiation of air into water flowing at high velocities in open channels has long been of great interest to hydraulic engineers, but detailed experimental information regarding the occurrence and the investigation of the flow mechanism of air-water mixtures has been elusive because of an inadequacy of accurate observations made by means of customary instrumentation. New instruments for measuring velocities of mixed flows and the air concentration in such flows have been devised at the St. Anthony Falls Hydraulic Laboratory of the University of Minnesota, at Minneapolis, so that velocity traverses and air-entrainment traverses can now be made accurately for widely diverse flow conditions, both for velocities and percentages of air entrained.