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.
Cauchy boundary conditions
Posted 28.12.2010, 01:25 GMT-5 0 Replies
Please login with a confirmed email address before reporting spam
I have a domain with a circular boundary. On this circular boundary, I want to implement Cauchy bcs - that is for a function u, I want to specify u and -n * grad(u) on the boundary. How exactly do I do this? In COMSOL, it seems that by choosing the Dirichlet bcs (from Physics -> Boundary settings --> etc.) we can almost do this because there are two equations to set: 1) R = 0 and 2) -n* (grad(u) +...) = G + dR/du^T * mu = 0. We can set R = u - c, to have u = c at the boundary. To set the normal derivative of u at the boundary, we can specify G appropriately, but then we have this Lagrange multiplier term. I want to get rid of this, that is to just have -n*grad(u) = G. How do I do this?
Thanks,
John Smith
Hello John Smith
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.