2 magnets moving in a still fluid

rjmcsherry · September 27, 2010, 10:39

Hello,
I am a relatively new CFX user and have an interesting problem that I hope someone may be able to help me with. I can't find what I am looking for in the ANSYS documentation.
Essentially I have two magnets in a stationary fluid, and due to an externally applied load one of them will start to move past the other, which will be mounted on a spring and is therefore free. I would like to know if there's any way that it may be possible to calculate and couple the force between the two magnets as they move relative to eachother through the fluid, in CFX. My aim is to model the magnet on the spring as a mass-spring-damper system, with the magnetic force of attraction/repulsion constituting an external load and the fluid providing hydrodynamic damping. Can anyone help me please?
I understand how to apply a time-varying external load to a structure using a Tabular Data input, but the challenge here appears to be introducing the coupling between the two magnets. Will it be necessary to use EMAG?
Many thanks in advance for any advice.

ghorrocks · September 27, 2010, 20:20

Not sure what you need to get this working, but it sounds manageable. Hopefully the EMAG option can do it. Coupling the EMAG stuff with a 6DOF solver should hopefully be possible but I can't guarantee that either.

You will just have to try it out and see what works.

rjmcsherry · September 29, 2010, 05:22

OK thanks Glenn, I'll give it a crack with EMAG. Unfortunately our license server has been down all week, so haven't been able to try anything.

September 27, 2010, 10:39	2 magnets moving in a still fluid	#1
rjmcsherry New Member Join Date: Sep 2010 Posts: 6 Rep Power: 16	Hello, I am a relatively new CFX user and have an interesting problem that I hope someone may be able to help me with. I can't find what I am looking for in the ANSYS documentation. Essentially I have two magnets in a stationary fluid, and due to an externally applied load one of them will start to move past the other, which will be mounted on a spring and is therefore free. I would like to know if there's any way that it may be possible to calculate and couple the force between the two magnets as they move relative to eachother through the fluid, in CFX. My aim is to model the magnet on the spring as a mass-spring-damper system, with the magnetic force of attraction/repulsion constituting an external load and the fluid providing hydrodynamic damping. Can anyone help me please? I understand how to apply a time-varying external load to a structure using a Tabular Data input, but the challenge here appears to be introducing the coupling between the two magnets. Will it be necessary to use EMAG? Many thanks in advance for any advice.

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September 27, 2010, 20:20		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	Not sure what you need to get this working, but it sounds manageable. Hopefully the EMAG option can do it. Coupling the EMAG stuff with a 6DOF solver should hopefully be possible but I can't guarantee that either. You will just have to try it out and see what works.

September 29, 2010, 05:22		#3
rjmcsherry New Member Join Date: Sep 2010 Posts: 6 Rep Power: 16	OK thanks Glenn, I'll give it a crack with EMAG. Unfortunately our license server has been down all week, so haven't been able to try anything.