Depth of flow 2

[Gulmitic]

Hi, I am calculating the depth of flow in a U-shaped channel, I know the flow, the depth of the channel and the radius of the semicircular base of the channel. I used manning equation but the answer does not satisfy me. Don't understand how to corelate the U-shape of the channel with the variables in the formula?

 

[TerryScan]

Do you have an understanding of what the variables in Manning's equation mean? It is fairly straight forward.
n = manning's n value
A = Area of flow (for your specific depth)
P = Wetted Perimiter (for your specific depth)
(Wetted perimeter is the surface of the "U" in contact with the water at your specific depth)
S = longitudinal slope of the channel

A & P will be the same as a circle up to the top of the circular section. For any higher depths, one will need to add the rectangular area of depth above the half circle to the area of the half circle for A. For P at higher depths, one adds the depth above the circlular section x 2 (each side) to the perimeter of the half circle.

 

[bimr]

Here is a free calculator that you can modify to your problem for demonstration purposes:

http://www.wq.uiuc.edu/dg/Equations/Mannings.exe

 

[stanier]

Download Flowpro2 and you will get information on depth of flow

 

[Gulmitic]

Thank you guyz, it was great help

 

[LAguy]

Wow thanks bimr ...that's great calculator you have there.