Nolapete- You are correct about the hydrostatic paradox & basic hydraulics (uniform pressure on surfaces of a fluid-filled container).
My formula is from an engineer. You can calculate the weight of 1 cubic foot of water yourself.
12" x 12" x 12" = 1728 /
231 (1 US gallon) =
7.48 gallons in a cubic foot *
8.33 lbs. per gallon =
62.31
Show me my error if that's wrong.
I compared my results with the results on the hydrostatic paradox page by using 62 and 600 ft. and came up with 18.6 tons. They showed 18 tons, so evidently rounded, but close enough. I said 62 was approximate.
However, I have doubts about the number you used regarding the weight of a cubic foot (ft^3) of water. I'm not trying to call you out or anything, but I've seen this a few times on various fish forums, converting units of volume (ft^3) to weight and/or converting flow rates to water velocity, etc. Using straight volume, my software says 1 ft^3 of water is equal to 7.481 Gallons. If we use 8 lbs/Gallon of water weight,
According to my roommate who works for PSI, a construction testing firm, water weighs 8.33 lbs. per gallon. I used that number.
That said, we all know that total dissolved solids can increase or decrease the weight. It doesn't matter what weight you use, the formula still works. I could put 59 in and it would still come out very close to what I have.
I get 59.848 lbs. per ft^3. Seems like a small difference, but you have a really BIG tank, so it adds up quick. Where did you get your 62 lb/ft^3 number?
See above.
Obviously I cant take into account any chemicals/treatments, so if this is a measurement you took from your own water, disregard the lower weight. All that said, your order of operations is incorrect (parentheses first)
Isn't order of operations multiply/divide then add/subtract? I shouldn't need parentheses then.
& your final answer (18,600) is essentially the square footage of 310 of your tank sides,
No, 12 ft. long * 5 ft. high = 60
60 * 310 = 18600
Until you can grasp that front to back DOES NOT matter, you won't be able to understand this. That's why I posted the link to the hydrostatic paradox page (which isn't mine btw) to show you examples. The best on that page that explains it is the Lake Mead/Lake Mudd one.
or volume (in ft^3) of your tank if it were 310 ft. deep front to back.
See above.
In addition, shouldn't exerted pressure be in PSI?
You're right, but I wanted to keep it simpler, so I left it as a total. In reality, the forward thrust PSI at the bottom of the tank is higher than the forward thrust at the bottom of the tank. That gets way too complicated to explain.
You evidently know there's a lot of scientific measurements out there that us common people have a hard time grasping. I know I do. I won't begin to try to explain it to others.
I could be wrong, but I believe your equation should have been:
(62 lbs * 5 ft) * 12 ft = 3,720 lbs total forward pressure
Using my (slightly rounded) numbers, I get:
59.85 lbs * 5 ft = 299.25 lbs per vertical foot of glass (not sq.ft.)
299.25 lbs * 12 ft = 3,591 lbs total forward pressure
I'm not sure about this part, but with 10,368 sq.in. of glass per wall, that is only about .35 lbs/sq.in (psi) by my calcs & 1.79 psi by your calcs.
2.1527 psi @ 62 lbs
I won't try to figure out why and where your equation is wrong other than the fact that when foot is used as the measurement on
http://www.ajdesigner.com/phppipehydrostatic/external_hydrostatic_pressure_equation.php
with 62 lbs the result is
external hydrostatic pressure (PG) = 310 pound/foot^2
I'm no scientist, and I'm not 100% sure, so...Let the games begin!!!!!!
I'm not trying to be right, but I did ask my friend to ask his wife who is an engineer and that site is what she gave him to give me.