I have been doing some DIYnamics with rotating water and non-rotating water. So I had a bucket filled with water on a rotating table, and waited for it to be in solid body rotation. I then dropped some droplets of fooddye in the water. I observed that the dye sank vertical to the bottom of the bucket without mixing with the water horizontally. I remember that my teather called this 2D turbulence. However, I can't find a reason for why the dye does not mix horizontally. What is so special with rotating water, that makes 2D tubulence occur and not 3D?
After this experiment was done, we added more dye. But now we mixed it gently with a stroke of a pen, to make turbulence. I then see some spirals being formed, so the water must mix a bit horizontally now. But why? And how does the rotating water affect turbulence?