Water Flow Calculator

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OK, now that I have some time perhaps I should elaborate a bit...

First calc-box is for calculating the capacity of a pipe or bulkhead opening (in other words, the maximum flow through a hole, before head loss due to pipe length, etc.)

The second calc-box is to calculate flow over any weir - be it the overflow into your C to C, in-tank "sump" box or weir to external downpipe.

The third calc-box is to calculate capacity of any "box", such as the corner-to-corner overflow.

The left and right colums in the first two calc-boxes allow for flow over two types of surfaces for the pipe or weir. It is perhaps not widely known, but a well rounded, smooth pipe or weir edge over which the water must flow can increase the capacity of the pipe or weir quite dramatically - enter the same data in both colums and see for your self...

Hennie
 
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Thanks Hennie.
 
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You're welcome :)

For those with a scientific / engineering interest, the following formulae, as found in the all time "Engineering bible": Technical Formulae by Kurt Gieck, 4th edition, 1979, were used in the spreadsheet:

Flow through base aperture, or small lateral aperture:
velocity (v) = Cv x Sqrt(2gH)

flow (Q) = Cd x A x Sqrt(2gH)
Q = volume of outlet flow (m^3/s)
A = cross sectional area perpendicular to fluid flow (m^2)
g = gravitational constant (~9.8 m/s^2)
H = "Head" of water (height of water surface above top of aperture)
Cv = velocity coefficient (for water it is 0.97)
Cd = discharge coefficient = Cc x Cv
Cc = contraction coefficient (use 0.62 for a sharp-edged aperture, and 0.97 for a smooth, well-rounded aperture)

Wow, this was more typing than I anticipated, and my food is getting cold - I will post Manning's formula for the "open channel" at a later stage...

Hennie
 

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