Calculate a flow rate?? Anyone

[mtcoins123]

so my question is does anyone have an equation to find the flow rate based on the thickness of the water flowing over the last baffle in a sump say if the head of the fall is 1.25 inches thick and the width is 16 inches is there a calculation for how many gallons per hour that would be?

[mtcoins123]

come on gotta be one math wiz or tank guru out there with this equation ???

[BeanAnimal]

You will want to use a weir calculation:

In this case a suppressed sharp crested weir is likely the closest match. You will want to search and read the explanations of how the equations work. But in general the accepted basic calculatuion is cubic feet per second = 3.33 * width in inches * (crest depth in inches)^3/2

For the dimensions you list, you are looking at somewhere just over 4,700 GPH I would estimate.

[macktab]

Here is a link to a website I have used for some work related tasks.
The equations are included.

http://www.engineeringtoolbox.com/we...ate-d_592.html

edit: use 32.2 ft/sec2 for "g" not the metric unit shown.

[mtcoins123]

would you mind teribly demonstrating the equation with my numbers i have a little trouble remembering the algebra i was taught so many years ago i would really apreciate it if i see it worked out i will be able to use it again easier

[mtcoins123]

^3/2 ?? lost me there

[Bk2Reefin]

try landscaping or pond forums, those guys gotta know that stuff for waterfall so they can calculate for the correct pump.

[mtcoins123]

Originally Posted by Bk2Reefin

try landscaping or pond forums, those guys gotta know that stuff for waterfall so they can calculate for the correct pump.

just needed the right search term lol waterfall was the key to a keyword search heres a link to an easy calc. in case anyone wants it

http://www.pondliner.com/product/wat...culator/topics

[mtcoins123]

Originally Posted by BeanAnimal

You will want to use a weir calculation:

In this case a suppressed sharp crested weir is likely the closest match. You will want to search and read the explanations of how the equations work. But in general the accepted basic calculatuion is cubic feet per second = 3.33 * width in inches * (crest depth in inches)^3/2

For the dimensions you list, you are looking at somewhere just over 4,700 GPH I would estimate.

i had given you aprox. measurements when i plugged in actual i came up with the 3400 gph thanks for your time though

[Bk2Reefin]

well glad my little bit of input helped in some way lol

I just remember reading post in the water garden forum about guys arguing about what pump will give a greater water amount within the waterfall. I do landscaping just not really the big time waterfalls.

[BeanAnimal]

That waterfall calculator uses the same basic weir equation

terh ^ operator is the POWER operator. In this case you are taking the (crest depth in inches) to the 2/3 power.