The Open Channel Flow Calculator is used to determine open-channel flow in circular pipes based on Manning's Equation:
V is the cross-sectional average velocity (m/s)
n is the Manning coefficient of roughness
Rh is the hydraulic radius (m)
S is the slope of the water surface or the linear hydraulic head loss (m/m) (S = hf / L)
For more information on Manning's Equation, see:
This calculator has been scaled to use English units. The Manning coefficient of roughness is built in for the following types of pipes: cast iron pipes in fair condition, riveted steel pipes, vitrified sewer pipes, concrete pipes, wood-stave pipes, planed-plank pipes, and smooth or corrugated semicircular metal flumes.
Engineering Calculator Disclaimer
Pipe Diameter (inches):
Height of Liquid in Pipe (inches)
Pipe Type:
Slope (elevation loss per length):

Engineering Calculator Disclaimer

IEEE GlobalSpec engineering calculators are free for individuals to use via this site under the terms and conditions set out under the Terms of Use of this web site and supplemented by this Engineering Calculator Disclaimer. These calculators are intended solely for general information and educational purposes, and are provided to help decrease the learning curve for those inexperienced in the engineering field and to give more experienced users additional reference tools.

The engineering calculators provided are not intended in any way as engineering advice or services, or as a solicitation for any engineering product or service. Any results from use of these calculators may not be applicable or accurate with regard to the individual circumstances, cannot be relied upon for anything, including, without limitation, engineering designs or decisions, and should not be the basis for any action or inaction on your part. Read Entire Disclaimer

Back to Top