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Unidirectional or bidirectional constraint?

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 PM EST
Posted: 5 years ago Dec 12, 2012, 1:41 PM 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.

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