When emptying bottles I’ve noticed that if the angle is such that liquid completely covers the opening, you get that “glug glug” staggered spastic flow whereas if there’s any amount of air flow, the stream is steadier.
Of course, a steady stream happens at shallower angles so there must be some trade off.
What’s the optimal way to empty a bottle (fastest empty time)? Is it straight down, or does the “glug” factor necessitate some other angle with constant airflow?
Assume standard 2 liter soda if you need to, but really I’m more interested in the more general equation if such a thing exists.
try to experiment. i can only relate my experience in beer drinking contests (speed, single bottle.) with my head tilted up, mouth and throat open like a funnel, i hold the mouth of the bottle to my mouth with the hand braced against my chin to steady the bottle. this way i achieve two things. 1) i can regulate the slant to prevent the bottle from glug-glugging, and 2) i can also regulate the amount that slides into my gullet (to keep ME from glug-glugging.) i usually win.
If you give it a slight spin before tipping it completely upside down, you can form a vortex where the air comes through the center and the liquid flows around the edges. You can empty a wine bottle in less than 5 seconds using this method.
A bendable straw inserted small end into the bottle big end bent to the side of the bottle will drain real fast as it allows air into the bottle as the liquid drains without the “chug chug” effect…
This is what I do when washing beer bottles for homebrewing. A quick flick of the wrist when you upturn it, and the water pours out 3x as fast as letting it glug, without having to concentrate on getting just the right angle.
An equation would be very difficult as it is going to relate to the shape of the bottle, size of the opening, length of the neck, height/width ratio of the bottle, how full is it to begin with, etc.