Menu

Discussion Forum

New Discussion
Filtrer

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 The information provided may be out of date.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.

Periodic boundary conditions in the PDE solver

Posted 27 juin 2011, 15:18 UTC−4 Modeling Tools & Definitions, Parameters, Variables, & Functions, Studies & Solvers Version 4.1, Version 4.2, Version 4.3 1 Reply

Schuyler Vowell
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

I'm working on a simple solution for a closure problem related to developing the governing equations for mass transfer in a porous media. This requires a solution to Laplace's equation in a cubic unit cell with a single sphere cut from its center. The sphere has a specified flux based on the surface normal vector, and the faces of the cube have a periodic boundary condition since we model our medium as an array of these unit cells in the closure problem.

I've tried specifying periodic boundary conditions on opposing faces of the cube, but they do not overwrite the default zero flux condition. How do I impose a periodic condition on the opposing faces of the cube in the PDE solver?

I realize that the boundary conditions will specify the solution up to an arbitrary constant--we have an additional condition that the integral of the result over the cube minus the sphere is zero which we can use to find the desired solution--does COMSOL require a specified value somewhere?

The computer I work at runs version 4.1, but also have access to a supercomputer running version 4.2 which I will use for more complicated geometries in the future. If there is any difference between the two please let me know. Thanks.
1 Reply Last Post 10 janv. 2013, 06:59 UTC−5
COMSOL Moderator

Hello Schuyler Vowell

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.

Wu Jia
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 10 janv. 2013, 06:59 UTC−5

Hi Vowell,

I also confronted the same problem as you did.

When using the periodic condition in the Weak form PDE Module, I found the zero flux setting is defined by default, and cannot be cancelled when setting the periodic boundary condition.

I want to ask that whether you have solved such a problem.

Many thanks for your reply.

Best regards,
Jia

PS: I am using COMSOL 4.3
Hi Vowell, I also confronted the same problem as you did. When using the periodic condition in the Weak form PDE Module, I found the zero flux setting is defined by default, and cannot be cancelled when setting the periodic boundary condition. I want to ask that whether you have solved such a problem. Many thanks for your reply. Best regards, Jia PS: I am using COMSOL 4.3

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