Not homework help, this is a real world application. I have a large "knife gate" valve used at the bottom of a hopper full of granular product. I need to know the hydraulic diameter (4x cross-sectional area / perimeter) in order to calculate the flow through it for a given opening width. The orifice of the knife gate is a 16" circle, and the flow is cut by a plate with a semicircular edge with a radius of 10.25"
In the picture above, the cross-hatched area is the area through which product can flow, if the knife gate is open to a width of 1.125"
I need to know cross-sectional area and perimeter (arc length a + arc length b) of the cross-hatched area.
Currently I am getting this data from AutoCAD. AutoCAD tells me the arc lengths and the area of the cross-hatch, so I move the knife in AutoCAD 1/8" at a time and record the arc lengths and area into a look-up table for a piece-wise linear scaling operation.
This is very tedious. I will continue the drudgery but I would much prefer a formulaic solution.
I have googled all of the things, and the results I get are much more complicated than I want them to be, and are exclusively solving for the area of two circles like this:
Not the crescent shape I need. And also not giving arc lengths/perimeter.
Is there any better way than what I'm already doing?
In the picture above, the cross-hatched area is the area through which product can flow, if the knife gate is open to a width of 1.125"
I need to know cross-sectional area and perimeter (arc length a + arc length b) of the cross-hatched area.
Currently I am getting this data from AutoCAD. AutoCAD tells me the arc lengths and the area of the cross-hatch, so I move the knife in AutoCAD 1/8" at a time and record the arc lengths and area into a look-up table for a piece-wise linear scaling operation.
This is very tedious. I will continue the drudgery but I would much prefer a formulaic solution.
I have googled all of the things, and the results I get are much more complicated than I want them to be, and are exclusively solving for the area of two circles like this:
Not the crescent shape I need. And also not giving arc lengths/perimeter.
Is there any better way than what I'm already doing?