Discussion Forum

Hi

if you use 2D MF you solve for the magnetic vector potential A so you have no dimensional dependent variables in there, so no "motion", for that you would need "solid" or some other physics including u the displacement vector. Then as MF needs also the air all around, indeed an ALE first to couple the geometry of the falling part and the air deformation would be required.

It's not alsways that simple to couple some "simple" physics model

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Good luck
Ivar

Hi Ivar, thank you for your quick response! I'll try to work on you answer.

And I was wondering, a particle in a flow. Is it possible to put the same iron bead in a laminar flow, and make the bead flow along with the fluid? And use the magnetic field to bend its path?

I know it is possible to attract particles with charged particle tracer but is that also possible with the bead i mentioned? Or would it be easier to model the beads as fluids with a very high viscosity?

Thank you in advance!

Mike

Hi

it all depends on what the air is supposed to do to your particles, you could consider vacuum and magnetic fields, + particles being aced on by some initial velocity and the interaction with the magnetic field (if you can define the appropriate materialproperties such that a magnetic fore might be derived, I havent tried that.

But you might also add a fluid flow, and add the fluid particle interaction, moving the particles, as well as slowing them when forced by the magnetic field outside the fluid flow lines

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Good luck
Ivar

Ivar thank you very much for your quick replies! You are a blessing. I've been working on it since my last post and tried your recommendations.

Well actually I am trying to simulate a water flow in a micro channel with ferromagnetic beads in it, these beads are attracted by magnetic forces which will drag the water and make it flow through the channel.

My new plan is to first simulate the magnetic field and calculate the forces which will act on the beads in the channel. And than use these forces in the flow to make the beads move through the channel.

Which physics would be the best to simulate this? I am using "Laminair Two Phase Flow, Moving Mesh" but still not successful. What is the best way to add the fluid particle interaction?

Cheers, Mike

Hi

I would say in your case the magnetic field is fixed, so MF or even MFNC should do once for that in stationary, then you do a sparate time series in fluid flow nitf, but I would expect that it's simpler to use the particle module for your magnetic beads as these interact with the fluid flow, and the magnetic forces

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Good luck
Ivar

Thank you Ivar,

I worked a few hours with the 'Particle Module'. I am now able to make the beads/particles move in the fluid with magnetic forces. However when I use this module the forces on the particles do not interact with the water. There is no velocity due to the drag force in the medium where the particles travel in. Is this possible with this module?

In all the examples it goes the other way around: The particles flow along with the medium. In my case the medium has to flow due to the magnetic forces on the particles.

And I don't know what you mean with "then you do a sparate time series in fluid flow nitf".

Thank you VERY much!

Mike

Hi

you are right the particles are generally added at the end and respond to the environmental forces, you want to inverse this ;) Interesting here I cannot help, I would suggest to ask "support" if nobody else can come with a good idea

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Good luck
Ivar

Hi guys,

I am kinda struggling with the same problem as Mike so I think it is time for some help. I am also trying to create a ferro fluid which is driven by a magnetic field :)

I have tried a lot of physics combinations like Mike and I cant seem to find the right one:

- Two phase flow, level set: The Volume force on the particle does not seem to work well? And the particle dissolves into the water. I know it must be possible with this one, I read about someone modeling the particle as a "hard sphere" with no slip boundaries, however this does not work for me. Do either one of you know how to model this? A hard sphere as a 'liquid'. I tried to change the surface tension and viscosity to non liquid numbers but I got weird results.

- The particle module as Mike described above, I came to the same conclusion :)

- Laminar two phase flow with moving mesh: This one works also quite well, but I can only put a prescribed velocity to the particle and no force or so.

- Fluid Structure Interface: This one seem to work the best, and I am still working with this one.

Hello, can you share the COMSOL file for this application. I have been struggling to make ferromagnetic micro beads to move under the influence of a magnetic force.
Thanks
Regards
Ahsan

Hey,

I'm working on something similar too. Would you mind sharing your model here? It would be of great help.

Thanks in advance,


Regards,
-Santosh

Hello,

I am trying to simulate a blood vessel with magnetic particles inside in 2D and trying to move them with a magnet but I can't move them under the influence of a magnetic force. Do I need to use charged particles or just the particle tracing?
Can you share the model to see what physics you used or share the proper physics for my problem?

Thank you in advance,
Zafiris

Did anyone found a solution? I need help because I can't figure it out my self. Thank you in advance