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In this article: cutthroat, flume, custom

One advantage that the Cutthroat Flume has always had over other short-throated flume like the Parshall or Trapezoidal was the ability to develop intermediate width flumes for one of the four standard lengths.   

But what if the standard lengths don’t yield a Cutthroat flume that fits the application?  The answer:  a custom Cutthroat flume!

A set of “unified discharge” calibrations were developed by Skogerboe for Cutthroat flumes so that it is not necessary to select one of the 24 standard sizes. 

So long as the custom Cutthroat flume conforms to the standard layout, a custom flume can be developed: 

  • Flat floor
  • “No length” throat
  • Inlet contraction ratio of 3:1
  • Outlet contraction ratio of 6:1
  • 0.1 < W/L < 0.4, W = width, L = length
  • Length is between 18-inches [45.72 cm] and 108-inches [274.3 cm]

custom stainless steel Cutthroat flume

Merkley presents five equations derived from regression analysis performed on Skogerboe's graphic results; the result of which is that both free-flow and submerged flow can be determined for custom Cutthroat flumes conforming to the above.  

Free-Flow Equation for Custom Cuthroat Flumes

free-flow equation for custom Cutthroat flumes

Submerged-Flow Equation for Custom Cuthroat Flumes

submerged flow equations for custom Cutthroat flumes

When compared to the parameters of the 24 standard Cutthroat flume sizes, the above equations have a maximum difference of less than 2%.


Get a quote for a Custom Cutthroat Flume today!


Source:  Merkley, G., BIE 5300 / 6300 (Fall Semester 2004) Irrigation Conveyance & Control:  Flow Measurement & Structure Design, Utah State University, 2004

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