Discussion Forum

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.