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ALE question

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Hi,

I'm interested in the transient effects of a moving charged object on a grounded one (see image).

I have first modelled this using a parametric sweep on the object's x position. But of course, this gives a series of steady state solutions and gives no information on transient induced currents/voltages etc. If I use a time dependant solver I'm not allowed to enter time dependant positions of geometry objects. As I understand, this is because the time dependant solver does not loop through the geometry and re-mesh for each time point, it can only use the original mesh.

I have since tried to use ALE to achieve this motion, by applying the "free-deformation" BC to the air domain and the ellipse and then the "prescribed mesh velocity" BC to the ellipse only (with a velocity in the x direction). The motion would go from one side of the grounded object to the other.

Unfortunately, I think this is too much motion for the mesh deformation to handle. Do I understand correctly that the ALE is unsuitable for this amount of motion (from one side of the picture to the other)? When I solve the model, I get a weird, unrealistic deforming of the electric field around the ellipse.

Either way, do you have any insight on the correct way to implement this amount of motion into a comsol model? ALE or something else?

Thanks and kind regards,
Dominic.


3 Replies Last Post 2013年10月29日 GMT-4 19:03
Sergei Yushanov Certified Consultant

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Posted: 1 decade ago 2013年1月25日 GMT-5 08:17
Dominic,

Use Form Assembly instead of Unity and sliding mesh functionality. You would need to define Pair Continuity BC at the sliding boundary. This way you will be able to model significant amount of motion without difficulty. See “Voltage Induced in a Coil by a Moving Magnet” from ACDC Model Library.

Best regards,
Sergei
Dominic, Use Form Assembly instead of Unity and sliding mesh functionality. You would need to define Pair Continuity BC at the sliding boundary. This way you will be able to model significant amount of motion without difficulty. See “Voltage Induced in a Coil by a Moving Magnet” from ACDC Model Library. Best regards, Sergei

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Posted: 1 decade ago 2013年1月25日 GMT-5 08:33
Thankyou Sergei, much appreciated.

I'll get on it now.
Thankyou Sergei, much appreciated. I'll get on it now.

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Posted: 1 decade ago 2013年10月29日 GMT-4 19:03
Hi Sergei,

I followed the example given in ACDC. Unfortunately, the solution diverges. I am trying to implement Nguyen et al paper
'Numerical study of a droplet migration induced by combined thermocapillary-buoyancy convection"

I have attached the code for your reference. I would appreciate your advise.

Regards,
Susant
Hi Sergei, I followed the example given in ACDC. Unfortunately, the solution diverges. I am trying to implement Nguyen et al paper 'Numerical study of a droplet migration induced by combined thermocapillary-buoyancy convection" I have attached the code for your reference. I would appreciate your advise. Regards, Susant

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