## Neumann BC with Static Current Solver

Numerical methods and mathematical models of Elmer
sbrialmont
Posts: 4
Joined: 14 Nov 2023, 04:39
Antispam: Yes

### Neumann BC with Static Current Solver

Hi,

I'm currently trying to model the stator of a motor but I have some trouble to apply the current density in the conducting part.

To simplify the situation as much as possible, I only consider one phase in static configuration. Everything is linear.
I'm using the StatCurrentSolver to simulate the current injection in the conductor based on the different models I could find related to this topic on the Forum.

When using Dirichlet BC (imposing the potential difference through the conducting domain), everything seems to work (At least I get a decent solution). However, I would like to obtain a somehow uniform current density by imposing the value of J instead of the potential (Neumann BC). But, in this case, I can't get any convergence.
As I'm very new on Elmer, I'm probably missing something quite basic.

(Here is the link to the mesh file in case you need it as the file is too big. Sorry for that...)
https://we.tl/t-TtYtygjKes

Thanks a lot,

Sebastien
Attachments
case.sif
raback
Posts: 4698
Joined: 22 Aug 2009, 11:57
Antispam: Yes
Location: Espoo, Finland
Contact:

### Re: Neumann BC with Static Current Solver

Hi

You need at least one node where potential is fixed. Otherwise there is mathematically no unique solution. Just a quick guess...

-Peter
Rich_B
Posts: 406
Joined: 24 Aug 2009, 20:18

### Re: Neumann BC with Static Current Solver

I'd say that is a very good guess...

See attached modified sif file.

Rich.
potential.png (47.67 KiB) Viewed 39 times
Attachments
case.sif
sbrialmont
Posts: 4
Joined: 14 Nov 2023, 04:39
Antispam: Yes

### Re: Neumann BC with Static Current Solver

Indeed,

Quick, but good guess !
The results look decent by imposing the potential value on one of the boundaries only.

Thanks a lot for the quick reply by the way.

Sebastien