svFSI github CMM Test case

[Aditya Bantwal]

Hello,

Hope you're well. I had run this FSI simulation from the svFSI-tests on github:

https://github.com/SimVascular/svFSI-Te ... MM-inflate

Considering it is a straight tube, I assumed that the displacement would be axis-symmetric. However, observing the two views of the tube from the front and back, the displacement patterns are different. Is this some kind of numerical error? Or is it that for FSI simulations the displacement field would not be axis-symmetric?

PS. This is the relative displacement: Calculated as the difference between the displacement after the FSI simulation - displacement after prestress simulation

Front

front.PNG (74 KiB) Viewed 594 times

Back

back.PNG (72.17 KiB) Viewed 594 times

[Aditya Bantwal]

Hello,

Just following up on this.

Looking forward to your response,
Aditya.

[Aditya Bantwal]

Could it be some sort of rendering issue with paraview?

[Hunor Csala]

Hi Aditya,

I'm running into the exact same issue. Did you manage to solve it by any chance?

[Aditya Bantwal]

Hi Hunor,

I managed to fix this issue by applying a stiffness value using the external tissue support boundary condition (Robin BC) in simvascular. approx. 1e3 in SI units

The issue I believe is that because we are fixing two ends of a long cylinder, some kind of vibration/oscillatory behavior is generated which leads to those weird displacement patterns.

Let me know if you come up with some other solution/reasoning.

Thanks,
Aditya

[Hunor Csala]

Hi Aditya,

I suspected it to be a meshing issue and it seems like it was. I managed to resolve it by creating a very fine surface mesh before creating the volume mesh.

Best,
Hunor

[Aditya Bantwal]

I see, thanks for sharing.

Best,
Aditya