Electrostatics with volume charge

[kevinarden]

Most variables in Elmer are per volume if it is 3D and per area if it is 2D, some are per mass.
the manual might specify

[drmike]

Do you see a ring charge in the potential output? A blob of charge should change the potential distribution - a blob of dielectric not so much.
I don't see any change from the charge present vs the charge not preset. So I'm doing something wrong!

Edit: are there any examples that have charged particles or volumes added as "body force"? Maybe I should try that out.

[kevinarden]

https://github.com/ElmerCSC/elmerfem/tr ... tat_source

[kevinarden]

I see this

potential.png (52.54 KiB) Viewed 161 times

[drmike]

Thanks, I will play with that. I dug into the StatElecSolve.F90 and it sure looks like this should have worked. Hopefully I'll figure out what I'm doing wrong soon!

[drmike]

I dumped all the x, y, z points using a write statement, and copied that to a file. I then used those to feed into my formula, and realized I wasn't doing what I thought. I also found that paraview is "sticky" and I had to reset the amplitude scale every time I read in a new run. My playing around with amplitude was very confusing until I realized that. So now I get what I told it to do which is not what I wanted. But at least I can see what I expected:

Screenshot from 2024-03-27 16-19-02.png (38.17 KiB) Viewed 152 times

I have a ways to go to understand how everything works, but at least I'm getting a clue.

[drmike]

Finally got what I wanted for the simple test.

Screenshot from 2024-03-27 17-03-29.png (98 KiB) Viewed 150 times

Now I have a lot more to learn, but I think I'll pause while I'm happy.