Menu

Discussion Forum

New Discussion
Filtern

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 The information provided may be out of date.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.

Global constraint

Posted 18.03.2013, 15:12 GMT-4 Version 4.3a 2 Replies

Morten Hygum
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Hi,

I am modelling thermodiffusion of moisture with the mathematical module. Is it possible impose a constraint to the concentration, c, in order to ensure it stays positive.
2 Replies Last Post 19.03.2013, 02:49 GMT-4
Nagi Elabbasi Facebook Reality Labs
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 18.03.2013, 16:37 GMT-4
A negative concentration is frequently a sign of an incorrectly defined physics, coarse mesh or large time steps in a transient analysis. In general you don’t need a constraint to enforce the concentration to stay non-negative.

Nagi Elabbasi
Veryst Engineering
A negative concentration is frequently a sign of an incorrectly defined physics, coarse mesh or large time steps in a transient analysis. In general you don’t need a constraint to enforce the concentration to stay non-negative. Nagi Elabbasi Veryst Engineering
Morten Hygum
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 19.03.2013, 02:49 GMT-4
Thank you for your response.

I am not using using the bulit-in modules. I needed to use the math module.
Thank you for your response. I am not using using the bulit-in modules. I needed to use the math module.

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