Air friction in rotating ring magnet

[Jaap]

TL;DR

Air friction in rotating ring magnet

As can be seen below we have 3 ring magnets. The middel one floats in between the other two. We want to know how to calculate the air friction of the middle ring magnet if this rotates.

 

[anuttarasammyak]

Hi. I do not have scarce knowledge of air friction and it seems complicated. Why don't you put your system in a vacuum chamber ? Without friction the intermediate disk would rotate forever theoretically.

 

[berkeman]

Welcome to PF.

As can be seen below we have 3 ring magnets. The middel one floats in between the other two. We want to know how to calculate the air friction of the middle ring magnet if this rotates.

First some questions -- How are the 3 ring magnets polarized? Vertically or horizontally or some mix? What stabilizes the middle ring magnet between the other 2? How do you generate a rotational force to spin up the middle magnetic ring?

And on your question about air resistance -- what have you found in your research so far?

Finally, is this question for schoolwork? If not for scholwork, what is the application? Thanks.