UCLA Spinlab has another great video demonstrating the effects of rotation on a fluid. In a non-rotating fluid, flow over an obstacle is typically three-dimensional, with flow moving over as well as around the object. But in a steadily rotating fluid, as shown in the latter half of the video, the flow only moves around the obstacle, not over it. This non-intuitive behavior is part of the Taylor-Proudman theorem, which shows that flow around an obstacle in a rapidly rotating fluid will be two-dimensional and confined to planes perpendicular to the axis of rotation. (For the mathematically-inclined, Wikipedia does have a short derivation.) This 2D flow creates what are called Taylor columns over the obstacle. The Taylor column is like an imaginary extension of the original obstacle, turning the puck into a tall cylinder, and it’s real enough to flow, which diverts around it as though the column were there. (Video credit: UCLA Spinlab)
Turning Into 2D
