1. As a result, corrections for submerged flow in Palmer-Bowlus flumes have not been published. 2. There are two conditions of flow that can occur in a Parshall Flume : free flow and submerged flow . 3. If H b / H a is greater or equal to S t then it is a submerged flow . 4. If there is submerged flow , adjustments need to be made in order for the Parshall Flume to work properly. 5. As a result, it is important to set the flume so that it does not experience submerged flow conditions. 6. Since H b / H a is greater than or equal to 0.7, it is a submerged flow . 7. For submerged flow a secondary head measurement ( Hb ) is required to determine the flume is submerged and the degree of submergence. 8. For submerged flow , a depth of flow needs to be taken upstream ( H a ) and downstream ( H b ). 9. The measurement calculations are the same as for free-flow in a standard Parshall flume, but submerged flow cannot be adjusted for. 10. Submerged Flow when the water surface downstream of the flume is high enough to restrict flow through a flume, submerged flume conditions exist.
