Menu

Discussion Forum

New Discussion
Filter

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 The information provided may be out of date.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.

Open Boundary Condition in Mathematics module

Posted Jan 13, 2014, 8:36 a.m. EST Heat Transfer & Phase Change, Modeling Tools & Definitions, Parameters, Variables, & Functions Version 4.3a 0 Replies

Clément Belleudy
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Hello,
I have built a 3D Heat-Air model of an air-permeability defect. Basically, air is flowing from the heated volume through cellulose insulation to the attic (not heated). Therefore, I see the coupling between air and heat transfer, and the influence on the temperature field.
The model works well, I am using an "open boundary condition" at the interface "insulation air" for heat. Now I intend to add moisture into the model. for that, I have added a PDE node with the moisture conservation, and I input a source term in the heat-equation.
I have 2 problems about that:
- I have not managed to write the local latent source term in Comsol: it seems that the heat source term Q of the heat equation can only be a numerical value in W/m3 (how to write nabla ...?)
- If I use the EDP node (in Mathematics module) instead of Heat Transfer for the heat equation, I am able to implement my source term, but not anymore the open boundary condition.
About the Mathematic mode and the open-boundary condition, I looked in the forum and it turned out that I am not the first to have this problem. I saw that the users solved their problem in using another module.

I would be very grateful if you could provide me some tips and advice about that.
Thanks a lot!
Clément
0 Replies Last Post Jan 13, 2014, 8:36 a.m. EST
COMSOL Moderator

Hello Clément Belleudy

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.

Suggested Content