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 The information provided may be out of date.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.

Defining a parameter/variable/function that varies along a cutline on a 2D model to be used for a BC

Please login with a confirmed email address before reporting spam

Hi all,

I need to implement a boundary condition that will change as it's being applied. I'm not sure if this is possible, but it seems like it should be.

Specifically, I'm using the Poisson's equation solver and am implementing a flux/source BC. I need the BC to be a positive value if the electric potential at the point along the cut-line interface that it's being applied to is negative, and for the BC to be negative if the electric potential along the cut-line interface that it's being applied to is positive.

I already know how to make the BC a conditional, so now I just need to figure out how to make the conditional dependent on some sort of variable that will change as it's being calculated. The only experience I have with this is constant parameter values. For example, I make the BC = -5*(VBG>0) + 5*(VB<=0) where the VBG term is a parameter in a parametric sweep. This will apply the BC as a constant condition all the way across the line I specify. But, what I really need is some sort of parameter that will change as it's being applied based on the electric potential at each specific solution node such that if you were to start at the left of the line and move right, the BC would change in polarity depending on the electric potential as you move across the line.

Does anyone know if this is possible?

Thanks,

Buck

0 Replies Last Post 2014/01/31 12:54 GMT-5
COMSOL Moderator

Hello Buchanan Bourdon

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.