Magneto-Hydro Dynamics - Ring Magnets

I am studying MHD effects in a stainless steel (non-magnetic) pipe with tap water passing through upon which has been slid a permanent ferroceramic ring magnet.

As I understand, two eddy currents of opposing rotations are produced within the pipe on either side of the magnet. If the north pole of the magnet is facing downstream, the first eddy current is rotating CCW when viewed from the end of the pipe where the water is entering. The second eddy current rotates CW.

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Please correct me if I am wrong.

Moving on, I have two questions.

  1. In the above case, if the water is spun through the pipe in a CCW direction, using an inserted vane, is its flow accelerated or retarded?

  1. What happens if instead of one magnet, two identical ones are forced together north to north poles? IOW in what configuration do the resulting eddy currents occur?

It seems to me that the two opposing eddy currents at the convergent north poles would effectively cancel, leaving only a uniform CCW rotation throughout the pipe.

I am speculating here, so any advice would be most appreciated.

Kevin Foster

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Kevin Foster
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This is barely related, but the geometry is sort of similar:

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
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John Larkin

Thanks John. That is an interesting design and use of convergent like poles.

Kevin Foster

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Kevin Foster

The fields from the outer coils theoretically induce zero signal into the middle one, and a bit of metal in the oil disturbs the symmetry and makes a blip. They run ballpark 100 KHz.

In a jet engine, you want as much advance warning as possible that metal bits are accumulating in the lube oil.

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John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  
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John Larkin

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