Hi David,


Concerning the FD update, it will take a while, as I encounter problems installing petsc4py and I need to wait for IT guy. So I'm working on the version of 15/06/15 for the moment.


I'm new to github, but this should work: https://github.com/mmtjs/lin_coupled
mmtjs/lin_coupled
Contribute to lin_coupled development by creating an account on GitHub.
I had an error in the previous formulation, so I redirived it and at the moment the solver is partitioned i.e. it doesn't require one matrix for the whole system, but just mappings of corresponding boundary nodes from one domain to the other (these work).


The issue is in lines 175-179, where the coupling terms are commented out
...
a_eta = trial * v * ds_t
L_eta = ( eta + dt*dot( n_w, grad(phi) ) ) * v * ds_t #+ dt/rho * phi * v * ds_v(2) - dt * Pw * v * ds_v(2)
...
More on it in the previous pdf file.

Cheers,
Tomasz


From: David Ham <David.Ham@imperial.ac.uk>
Sent: 23 September 2015 10:27
To: Tomasz Salwa [RPG]; firedrake
Subject: Re: Firedrake issue
 
Hi Tomasz,

Welcome back.

Let's get through a few preliminaries.

First, if you haven't used firedrake for 2-3 months then it will be quite out of date. You need to update to the current version. You can do this using your existing install and update all the packages, or you can use the new installer to get a new installation which will also have an attached update script. See http://firedrakeproject.org/download.html
Obtaining Firedrake — Firedrake 0.11.0-658-ge79e125-dirty ...
Running firedrake-install with no arguments will install firedrake in a python virtualenv created in a firedrake subdirectory of the current directory.

Next, it's much better to have this sort of conversation on the Firedrake list. This keeps everyone in the loop and enables other people to intervene when I say something stupid ;). I have taken the liberty of adding you to the list and I'm replying to the list now so that this conversation ends up there.

Now, we need to be talking about code, not only maths, so please push what you're working on to a git repository on github or bitbucket so we can see what's going on.

Finally we can start to think about the actual problem. I think that last time we talked about this, we discussed setting up a mixed mass matrix across the two domains and checking that projection works. Does that still  work (and can you post some code to a repository which does this)?

Once we get past that then we need to talk about how to assemble forms on the boundary facets. This will involve doing some mucking around with maps, because at the moment the facets belong to two different meshes. We need to think a little about how to do that, but we can do so when the first steps work.

Cheers,

David


On Tue, 22 Sep 2015 at 12:54 Tomasz Salwa [RPG] <mmtjs@leeds.ac.uk> wrote:

Dear David,


I was busy in the recent months and could not work on the fluid-structure interaction problem. Now I returned to it and reformulated it.


I am getting the following error:


RuntimeError: Nonlinear solve failed to converge after 0 nonlinear iterations.
Reason:
   Inner linear solve failed to converge after 10000 iterations with reason: DIVERGED_MAX_IT


but the problem is with the proper formulation in Firedrake.

I include the pdf with it. Would you be able to help me with this?


Regards,

Tomasz



-----

Tomasz Salwa

PhD Research Student

University of Leeds

http://www1.maths.leeds.ac.uk/~mmtjs