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Dynamics of a tank

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jlarocque

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Jun 10, 2003
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I am designing a rectangular that will be on a trailer and would like to know where to determine the forces due to liquid sloshing when stopping.

How do I determine these forces?

JL
 
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I will be putting baffles but I am trying to model/determine the forces created when stopping the trailer the tank will sit on.
a) forces on the tank's walls
b) forces transmitted onto the trailer

JL
 
Hmmm interesting questions, my 2 cents at worst case (with out going into kinetic analysis) would be to calculate the g load when stopping and then multiply that by the mass of the fluid and then divide that number by the area of half the tank. This will at least get you to a pressure on the walls on the front part of the tank and then you can calc out your stress on the walls. At least this will be my first pass just to see what the numbers might be.

Does it have to be rectangular? There are equations for stress for cylinder tanks.


Tobalcane
"If you avoid failure, you also avoid success."
“Luck is where preparation meets opportunity”
 
Of course the pressure would havee a gradient. For 1G deceleration (not a bad assumption for worst case), imagine the tank tilted forward 45 deg and gravity increased by 40%.

Engineering is the art of creating things you need, from things you can get.
 
My tank needs to be rectangular. Approx 8'x8' x 30" high. Will be on a trailer and built to DOT and UN standards. Tank will have baffles to diffuse the energy created by sloshing but I was curious to see if simple formulas existed for a equivalent force applied when braking.

JL
 
Any high school physics textbook will have all the equations you would need to determine "equivalent force applied when braking".

Determining what to do with that number you have calculated might require referencing some college-level textbooks, or class notes.
 
Without looking at the literature on the subject, my first inclination would be to treat it like a fire hose shooting water against a wall; this would give an initial and maximum pressure equal to Bernouli's formula for stagnation pressure.

p=rho*V^2/2g

where I assume a sudden stoppage of the vehicle.



 
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