Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

Transition BC + reduced formulation

Please login with a confirmed email address before reporting spam

Hi to all,
my trial model involves a cube of Si inside a sphere of air.
The cube is "submerged" in an external magnetic field and on one of its surfaces a transition BC is applied.
To model the external field I've activated the "Background field" option so that the solver solves for the reduced field.
Any kind of simulation with this combination (transition bc + reduced formulation) fails with the following error:

**********************************
Failed to evaluate the variable Jacobian.
- Variable: mod. tAz
- Geometry 1
- Boundary: xx (the boundary number on which the transition BC is applied)
**********************************

If I solve the same problem putting a field source inside the model, or using the reduced formulation with the transition BC deactivated, no error is displayed.

Is it a bug, or am I missing something about the underlying physics?

Thanks in advance for the answers.

Alessandro

0 Replies Last Post 17 set 2012, 04:31 GMT-4
COMSOL Moderator

Hello Alessandro Ricci

Your Discussion has gone 30 days without a reply. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help.

If you do not hold an on-subscription license, you may find an answer in another Discussion or in the Knowledge Base.

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.