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

Fri Jan 7 12:45:11 CST 2022

Le ven. 7 janv. 2022 à 19:23, Matthew Knepley <knepley at gmail.com> a écrit :

> On Fri, Jan 7, 2022 at 12:58 PM Thibault Bridel-Bertomeu <
> thibault.bridelbertomeu at gmail.com> wrote:
>
>>
>> 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 ?
>>
>
> Yes, the idea is as follows. Each field also has a label argument that is
> the support of the field in the domain. Then we create PetscDS objects for
> each
> separate set of overlapping fields. The current algorithm is not complete
> I think, so let me know if this step fails.
>

Ok, thanks.
I’ll let you know and share snippets when I have something started !

Talk soon ! Thanks !

Thibault

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