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

[Thibault Bridel-Bertomeu]

Hi Matthew,

Le ven. 7 janv. 2022 à 14:44, Matthew Knepley <knepley at gmail.com> a écrit :

> 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.
>

Yes the way I see it is more of a single mesh with two distinct regions to
distinguish between the fluid and the solid. I was talking about two meshes
to try and explain my vision but it seems like it was unclear.
Imagine if you wish a rectangular box with a sphere inclusion: the sphere
would be tagged as a solid and the rest of the domain as fluid. Using Gmsh
volumes for instance.
Ill check out the SNES example ! Thanks !


>
>> 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.
>

Wow so it seems like it’s the exact same thing I would like to achieve as
the rocket engine example.
So you have a single mesh and two regions tagged differently, and you use
the DmPlexFilter to solve FVM and FEM separately ?

Thanks !

Thibault


>   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/>
>
-- 
Thibault Bridel-Bertomeu
—
Eng, MSc, PhD
Research Engineer
CEA/CESTA
33114 LE BARP
Tel.: (+33)557046924
Mob.: (+33)611025322
Mail: thibault.bridelbertomeu at gmail.com
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