For a typical two liter bottle, what angle should it be held at to allow it to empty the fastest?

Question

What angle allows the best combination of liquid leaving and air entering, thus emptying the bottle most quickly?

Answer 1

From a theoretical perspective, this is actually a very complex problem in fluid mechanics involving three dimensional unstable fluid motion with complex boundary conditions and higher order effects such as viscosity. I like to call such problems "squishy". From person experience, though, you want to tilt the bottle as much as possible without the flow becoming unstable. You know, all urgly with the air entering the bottle as bubbles. In other words, it's a problem best resolved empirically next time you're thirsty.

Answer 2

The bottle should be held at a 135 degree angle in reference to the container you are pouring the liquid into.

Answer 3

45

Answer 4

put a curved straw in there and you can turn it upside down and it'll be empty in seconds.

Otherwise, 90° is actually the best. It will take big gulps of air but unload more quickly.

Answer 5

keep the angle of the fluid to the ground at 45 degrees; you'll have to adjust the tilt of the bottle to maintain this as the fluid goes out.

Answer 6

45 Degrees or if you shake it vigour0usly 90 degrees, it will then spin to left in southern hemisphere, spin to the left in western hemisphere, creating a vortex which empties the bottle very quickly.

Answer 7

perfectly vertical

if you slosh the bottle in a cirular motion to cause a whirlpool, the air can get in through the center of the vortex while the water comes out the sides.

Answer 8

It depends on the size of the opening, which does vary.

Bigger the opening, the closer to vertical.

Answer 9

about 45 degress I would say

Answer 10

180°... upside down and swirling it slightly in a counter clockwise motion.