• # Thread: Nomograph- based on Mannings Equation

1. ## Nomograph- based on Mannings Equation

http://www.tpub.com/content/armyengi...N5465A0078.htm

This one is not as straight forward as it could be. I have some hard copies that give rate in gallons/ sec or cubic ft/ sec.
This will give a good idea of gravity pipe flow, it does not account for head pressure, or pump pressure.
For those you need Bernelli's Equation, a bit more complicated.
Last edited by GHouse; 05-19-2009 at 06:33 PM.

2. omg...

Thanks for sharing!
You're my hero! You must know how to equate all those numbers to actual
use... but me... I'm lost.

How the heck do you figure the Roughness Coefficient to use for a pvc pipe?
Or a pipe I've heated and bent?

It's pretty darn cool... but I wish I was better at math...

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Thanks. At first glance I thought this was going to be another one of those "I know what I'm talking about, why don't you?" horrors with no units or definitions, but most of the necessary info is there. Do you have a link to the roughness coefficients for common types of pipe?

Is "slope" the difference in water levels divided by the length of the pipe? If so this will be very useful.

4. Slope is Rise / Run, or the change in elevation divided by the length of the run of pipe in this case. Roughness coefficents are in any good hydraulic reference, but you only need a few.
There are great formulas for open channel flow, channels, stone inlets or outlets and weirs.
Last edited by GHouse; 05-21-2009 at 09:31 PM.

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Ah, this is for open channels.

Steve, a quick web search turned up 0.009-0.011 for PVC.
http://www.lmnoeng.com/manningn.htm

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