[petsc-users] Fluid-Structure interaction with multiple DMPlex

[Matthew Knepley]

On Fri, Jan 7, 2022 at 5:46 AM Thibault Bridel-Bertomeu <
thibault.bridelbertomeu at gmail.com> wrote:

> Dear all,
>
> First of, happy new year everyone !! All the best !
>

Happy New Year!


> I am starting to draft a new project that will be about fluid-structure
> interaction: in particular, the idea is to compute the Navier-Stokes (or
> Euler nevermind) flow around an object and _at the same time_ compute the
> heat equation inside the object.
> So basically, I am thinking a mesh of the fluid and a mesh of the object,
> both meshes being linked at the fluid - solid interface.
>

First question: Are these meshes intended to match on the interface? If
not, this sounds like overset grids or immersed boundary/interface methods.
In this case, more than one mesh makes sense to me. If they are intended to
match, then I would advocate a single mesh with multiple problems defined
on it. I have experimented with this, for example see SNES ex23 where I
have a field in only part of the domain. I have a large project to do
exactly this in a rocket engine now.


> First (Matthew maybe ?) do you think it is something that could be done
> using two DMPlex's that would somehow be spawned from reading a Gmsh mesh
> with two volumes ?
>

You can take a mesh and filter out part of it with DMPlexFilter(). That is
not used much so I may have to fix it to do what you want, but that should
be easy.


> And on one DMPlex we would have finite volume for the fluid, on the other
> finite elements for the heat eqn ?
>

I have done this exact thing on a single mesh. It should be no harder on
two meshes if you go that route.


> Second, is it something that anyone in the community has ever imagined
> doing with PETSc DMPlex's ?
>

Yes, I had a combined FV+FEM simulation of magma dynamics (I should make it
an example), and currently we are doing FVM+FEM for simulation of a rocket
engine.

  Thanks,

     Matt


> As I said it is very prospective, I just wanted to have your opinion !!
>
> Thanks very much in advance everyone !!
>
> Cheers,
> Thibault
>
>

-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener

https://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/>
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