Requirements for Water Spout pressure trick, at 100 scale?

[mgmguy]

Hello this is my first post, so if I am supposed to move this to another forum section please advise I would be happy to

http://foryourwater.com/mm5/graphics/00000001/3_gallon_dispensing_water_bottle_lg.jpg

As for my question, I am referencing the example of a water dispenser above, after a certain amount of flow, the water simply won't come out anymore. I assume this is because the amount of pressure/vacuum within the bottle is higher than the outside environment on the other side of the spout. Only until the lid is opened, shall the water then flow again. If someone is to look closely, they will see a level of water being suspended in mid air due to this, inside the spout.

I am curious of the requirements to do this in something let's say 5 feet wide in diameter. Is there a way to calculate the pressure required? I am wondering the pressure needed to accomplish this and if its possible

thanks

Matt

 

[etudiant]

The limiting element is the size of the spout. If it is wider than a fraction of an inch, the flow will become intermittent, as air bubbles go up the spout.

 

[jim hardy]

I think it's:

...pressure(psi) inside LESS than pressure outside by this amount:

...[density of water (in lbs per cubic inch)] X [depth of water(in inches) inside above center of spigot]

can you explain why?