Prescribed moition FSI with the new version

[MohammadAli_Daeian]

Hello everyone!

I have a question regarding the new version of the openLB. If one uses a a series of stl files describing a prescribed motion of the structure, apart from the procedure that is needed to translate the stl files to the structure grid within the solver, is there any other modification required. Specially considering the fact that this prescribed moition does not decribe a rigid structure motion as it is in the current version.

Thanks,
m

[avrachan]

Hi,

If you can describe the prescribed motion as a series of translations and rotations to the initial STL file, then it is straightforward adaptation of the examples/showcase/centrifugalpump example.

Specially considering the fact that this prescribed moition does not decribe a rigid structure motion as it is in the current version.

Can you explain this?

If the series of STL files involve deformation/fracture etc, then I’m not sure how one can capture its effect of the fluid, which might be something you want to consider.

• This reply was modified 4 months, 2 weeks ago by avrachan.
• This reply was modified 4 months, 2 weeks ago by avrachan.

[MohammadAli_Daeian]

Yes, that is the main issue. The structure mesh evolution involves deformation. I am not sure how I could modify the code to incorporta this behavioure.
I beielve this requires some development whithin the current version, however not sure which headers/functions should be modified for this purpose.

[avrachan]

You can probably write a function which loops through all the nodes that was inside the STL in the previous timestep but not inside the new STL, with equilibrium values. This might work if the deformation is not too drastic.

But you would still need to specify some velocity to the STL otherwise how will the fluid interact with the object.

[MohammadAli_Daeian]

Of course! A velocity must be specified for the STL mesh. However, my question concerns the deformation of the mesh. If the structure undergoes significant deformation, generally what modifications are required in the solver to handle such prescribed motion?

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