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How to prevent fluid mesh from degradation in fluid - structure - interaction (fsi)

Posted 28 nov. 2016, 09:19 UTC−5 MEMS & Nanotechnology, Fluid & Heat, MEMS & Piezoelectric Devices, Computational Fluid Dynamics (CFD), Microfluidics, Mesh, Modeling Tools & Definitions, Parameters, Variables, & Functions, Studies & Solvers, Structural Mechanics Version 5.0, Version 5.2a 2 Replies

Alexander Werth
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Hello community!

I use (fsi) module for modelling of vocal fold vibrations in 2D. At certain conditions the solid (vocal fold) deforms the fluid mesh too much resulting in mesh collapsing / degradation.
How could I prevent fluid mesh from collapsing/degradation?
Is it possible to define an offset or to limit the displacement of the solid when it reaches a certain value?


Many thanks in advance

With kind regards

Alexander
2 Replies Last Post 28 nov. 2016, 15:05 UTC−5
Jeff Hiller COMSOL Employee

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Posted: 8 years ago 28 nov. 2016, 09:43 UTC−5
Hello Alexander,
For you r specific case where your geometry may approach or reach a topological change, this blog may be helpful:
www.comsol.com/blogs/tips-using-wall-distance-interface/

A couple of other useful blogs on moving meshes are:
www.comsol.com/blogs/model-translational-motion-with-the-deformed-mesh-interfaces/
www.comsol.com/blogs/deformed-mesh-interfaces-rotations-and-linear-translations/

Best regards,
Jeff
Hello Alexander, For you r specific case where your geometry may approach or reach a topological change, this blog may be helpful: https://www.comsol.com/blogs/tips-using-wall-distance-interface/ A couple of other useful blogs on moving meshes are: https://www.comsol.com/blogs/model-translational-motion-with-the-deformed-mesh-interfaces/ https://www.comsol.com/blogs/deformed-mesh-interfaces-rotations-and-linear-translations/ Best regards, Jeff
Alexander Werth
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Posted: 8 years ago 28 nov. 2016, 15:05 UTC−5
Hello Jeff,

many thanks for your quick response and useful hints!
The blog post on "Tips for Using the Wall Distance Interface" is new to me.
I'm gonna study it carefully. It could be a key.
I've attached a picture (gif-animation; there are very first time steps of the simulation when the vocal folds abduct and phonation begins) so it would be more clear what I'm working on.
My first idea was to solve the problem by using "contact functionality".
Unfortunately, contact and fluid - structure - interaction conditions can not be assigned to the same boundary simultaniously (I tried it out).
Presently I would like to handle degradation of the mesh during adduction of the vocal folds by introducing of an offset in comination with a nonlinear boundary load acting like a spring.


Best regards

Alexander
Hello Jeff, many thanks for your quick response and useful hints! The blog post on "Tips for Using the Wall Distance Interface" is new to me. I'm gonna study it carefully. It could be a key. I've attached a picture (gif-animation; there are very first time steps of the simulation when the vocal folds abduct and phonation begins) so it would be more clear what I'm working on. My first idea was to solve the problem by using "contact functionality". Unfortunately, contact and fluid - structure - interaction conditions can not be assigned to the same boundary simultaniously (I tried it out). Presently I would like to handle degradation of the mesh during adduction of the vocal folds by introducing of an offset in comination with a nonlinear boundary load acting like a spring. Best regards Alexander

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