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

[Thibault Bridel-Bertomeu]

Le ven. 7 janv. 2022 à 14:54, Matthew Knepley <knepley at gmail.com> a écrit :

> On Fri, Jan 7, 2022 at 8:52 AM Thibault Bridel-Bertomeu <
> thibault.bridelbertomeu at gmail.com> wrote:
>
>> 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 ?
>>
>
> With a single mesh, you do not even need DMPlexFilter. You just use the
> labels that Gmsh gives you. I think we should be able to get it going in a
> straightforward way.
>

Ok then ! Thanks ! I’ll give it a shot and see what happens !
Setting up the FVM and FEM discretizations will pass by DMSetField right ?
With a single mesh tagged with two different regions, it should show up as
two fields, is that correct ?

Thanks,

Thibault


>   Thanks,
>
>      Matt
>
>
>> 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
>>
>
>
> --
> 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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