I've never really understood circles...

warrenslaney

Well-known member
Joined
Jun 13, 2006
Messages
2,959
Location
Youlgrave
I need to find the area of fluid in a sewer pipe.

The pipe is 225mm in diameter. The depth of fluid in the pipe is 180mm.

Can anyone help please? The dam thing is robbing my river of its flow.

Thanks
 

oldgold

Well-known member
Joined
Jan 27, 2014
Messages
2,940
The area is just shy of 40000mm2.......39760.ish
Multiply that by 180 for volume in cubic mm
And then divide by 1000 for volume in cubic centimetres
Divide by another 1000 for litres
 

James9118

Well-known member
Joined
May 26, 2009
Messages
2,161
Location
Hampshire
Total area of pipe = 39,760 mm^2

Area unfilled by fluid = 5,661 mm^2

Hence, area filled by liquid = 34,099 mm^2 (or 86%)

James
 
Last edited:

oldgold

Well-known member
Joined
Jan 27, 2014
Messages
2,940
Ah hah... I see what I have done...I have calculated for a pipe stood on its end with a height of fluid in it ........rather than what James has done which is undoubtedly correct, of a pipe on its side


:eek::D
 

Scratch

Banned
Banned
Joined
May 5, 2007
Messages
15,168
Location
Chorley
I need to find the area of fluid in a sewer pipe.

The pipe is 225mm in diameter. The depth of fluid in the pipe is 180mm.

Can anyone help please? The dam thing is robbing my river of its flow.

Thanks
Area = π r²

3.14 x 112.5² (12656.25) = 39740.625mm

180 = 80% of 225

80% of 39740.625mm = 31792.5


Err.... ish.. I think.
 

James9118

Well-known member
Joined
May 26, 2009
Messages
2,161
Location
Hampshire
Last calc in the page ( radius of 112 and height of 180 ), you are trying to calculate the area of a segment.

= 33940mm2

Online calculator: Circular segment
If you're going to use that calculator then you need to set r=112.5 and H=45. You then take away the answer from the area of the complete circle and hey presto you get the answer given in post 3
 
Last edited:

williegunn

Well-known member
Joined
May 16, 2006
Messages
5,878
Location
Carron Speyside
Do you not need a time element, to discover how much water is being removed?
If the pipe is 225mm and full up to 180mm but sealed at both ends no water is being taken.
 

luke troutstalker

Well-known member
Joined
May 19, 2011
Messages
11,359
Location
Cheshire.
If you're going to use that calculator then you need to set r=112.5 and H=45. You then take away the answer from the area of the complete circle and hey presto you get the answer given in post 3
Surely the segment can be either? Either 180 or 45 ?

112.5 ! :D
 

warrenslaney

Well-known member
Joined
Jun 13, 2006
Messages
2,959
Location
Youlgrave
Do you not need a time element, to discover how much water is being removed?
If the pipe is 225mm and full up to 180mm but sealed at both ends no water is being taken.
Correct. Thanks. My flow reader says 0.98. I'm told it reads in meters. I'm expecting the answer to be between 5 and 20l/s.
 

luke troutstalker

Well-known member
Joined
May 19, 2011
Messages
11,359
Location
Cheshire.
I haven't worked it out both ways to prove it otherwise, but I seem to remember you are of a scientific bent, so I'll take your word for it :thumbs:
 

Latest posts

Top