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fea user May 8, 2006 17:18

Fluid properties
Is it possible to give magnetic properties (permeability, conductivity) to fluid domain (for example welding)? Or how can I use an ANSYS magnetic analyses results as an CFX load or boundary condition?

opaque May 8, 2006 17:28

Re: Fluid properties
Dear fea user:

Could you please let us know what your application is?

Are you trying to simulate magnetic forces in the fluid (Lorentz)? or heat dissipation (Joule) ?

Do you already solved the problem on the magnetic/electric side ? or you still have to do so?

Is it a transient magnetic/electric simulation? Does include AC currents, or just DC?

The answers depends on the problem?

Good luck,


fea user May 9, 2006 10:01

Re: Fluid properties
Dear Opaque,

I don't know which apps (fluent, cfx, or other) could be the better choosing to simulate magnetic-fluid interactions (like welding, electrode-electrolyte, steel melt in furnace). I'd like to use magnetic forces, Lorentz-force, and Maxwell-equations on a fluid model for CFD simulation. The magnetic part of analyse is done. To simplified the problem It's a static magnetic field. There are some coils around an induction furnace with steel melt. This situation the magnetic field generates the fluid (melt) flowing.

Regards fea user

opaque May 9, 2006 10:12

Re: Fluid properties
Dear fea user,

Within the ANSYS CFX 10.0 solver there is an implementation of the Magnetic Vector Potential, and Electric Potential (for conductor materials). If you use it, it will automatically add the Lorentz forces and Joule heating to the momemtum and energy equations respectively..

If you already have the magnetic induction vector (B), and the Current Density (J), you could use them as input and the ANSYS CFX solver will compute the Lorentz/Joule term again..

A third alternative for you is to create a subdomain over the region the magnetic field is applied, and compute the Lorentz force yourself (JxB) as a momemtum source with Cartesian components.. Do not forget to account for the linearization coefficients since the source term depends on velocity (for some cases it is very important for robustness)

For the first two alternatives, you must contact the CFX help desk and request information (configuration files) of how to activate the MHD beta models in 10.0

Good luck,


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