Few days ago I played with ball(filled with air) in swimming pool. I observed interesting phenomenon.
When I released a ball from 3 meters depth the ball barely jumped above the water surface but when I released it from 50 cm depth it shoot out of the water like nothing.
I observed when released from 3 meter depth the ball goes up in zig-zag trajectory but from 50 cm depth is goes in straight line.
I would be very interested in calculating optimal depth from which the ball would jump the highest above the water surface. And as well I would like to calculate trajectory of the ball under water.
It is obvious that simple drag formula won't help here.
I guess that the zig-zag patterns is happening because there might be something like Karman vortex street behind the ball.
So have anyone idea how to calculate this? Or can you point me to the right literature?
Edit: I forgot one observation I made. It seamed to me that the ball when released from 3m depth was rotating when it hit a surface and that might prevent the jump.
Best Answer
For the reference of others who might be interested in this here's an article and the peer reviewed publication linked from it that cover this question in a fair amount of detail and has interesting videos demonstrating the different underwater behaviours.
https://phys.org/news/2016-11-pop-up-effect-buoyant-spheres-dont.html https://doi.org/10.1103/PhysRevFluids.1.074501