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 The information provided may be out of date.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.

Unidirectional or bidirectional constraint?

Please login with a confirmed email address before reporting spam

Dear all,

Before I read the documentation. Bidirectional constraint is said to be equivalent to pointwise constraint, and these two are different from unidirectional constraint (not only numerics). Honestly I don't know the real difference, but I tend to use bidirectional ones in many cases.

I just find, however, Dirichlet boundary condition in COMSOL has unidirectional as the default type. There should be a reason why unidirectional type is preferred. Does anybody know this? Thanks!

Pu.

1 Reply Last Post Dec 12, 2012, 1:41 p.m. EST

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Dec 12, 2012, 1:41 p.m. EST

In the documentation, it's mentioned that bidirectional constraint has stronger influence on Neumann BC, thus in several specific cases unidirectional type is necessary to enforce the boundary conditions correctly. But what's the difference for usual cases where unidirectional is not "necessary"? When are the two types equivalent?

Thanks!
--
Pu, ZHANG ??
Departamento de Física Teórica de la Materia Condensada,
Universidad Autónoma de Madrid,
Madrid, Spain.
In the documentation, it's mentioned that bidirectional constraint has stronger influence on Neumann BC, thus in several specific cases unidirectional type is necessary to enforce the boundary conditions correctly. But what's the difference for usual cases where unidirectional is not "necessary"? When are the two types equivalent? Thanks! -- Pu, ZHANG ?? Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, Madrid, Spain.

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.