From: Roy Stogner <roy@st...> - 2008-08-01 17:50:00
-------- Forwarded Message --------
From: Adam C Powell IV <hazelsct@...>
Subject: Re: [Libmesh-users] about conjugate heat transfer problem
Date: Thu, 31 Jul 2008 13:44:33 -0400
On Thu, 2008-07-31 at 08:09 -0500, Roy Stogner wrote:
> On Thu, 31 Jul 2008, luyi wrote:
> > Some one had asked you about the multi-physical problems using libmesh,
> > and you tell us you are working the conjugate heat transfer problem.
> > As the question "Associating more than one mesh to EquationSystems", I
> > want to perform fully implicit coupling(without operator splitting) and
> > use the Newton-Krylov method to solve conjugate heat transfer problem,
> > the difference is that I am not using stagger mesh, only one mesh
> > departed to domain A and domain B, the variables in domain A are
> > rho,u,v,w,E,k,w and in domain B only T, and I want to assemble the
> > Jacobian matrix and the rhs together, can I using only one
> > EquationSystems and one mesh to implement this?
> At the moment I think the answer is "not efficiently". Although our
> meshes can be flagged with subdomain ids, our DofMap still assumes
> that every subdomain in the mesh has the same variables defined on it.
> What we need is an API for the user to say "this variable only exists
> on subdomains 1, 5, and 13", as well as the DofMap code to respect
> those requests. Unless you want to dig into the library source code
> and add that feature (for which a patch would be much appreciated,
> naturally), I think the best you can do for a fully coupled solve is
> define all variables everywhere, then manually restrict T to be 0 on
> domain A and all the other variables to be 0 on domain B.
This is a neat approach, which I could use myself in a separate problem.
One issue though: how do I get, say, T to be 0 on domain A, when it is
non-zero at nodes on the A-B boundary? Do you have any examples?
I may have some time to investigate a patch to the DofMap code at some
point, and if the above approach works (to demonstrate a base case
solution) will start looking into it in the next couple of weeks...
Adam C. Powell, IV http://www.opennovation.com/
P.O. Box 249 apowell@...
Newton, MA 02464-0002 USA (617) 290-8831
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