Subject: [Unicorn-dev] About Remeshing of FSI Problem

From: "feng hobble" <[email-masked]>
Date: Tue, 12 Feb 2008 18:59:12 -0800

Hi,

I ran a case provided in unicorn-kth package which is a bar fixed vertically
on the top wall of a horizontal channel, blocking about half of the channel
passage.
This is exciting for me. Finally I can run a FSI problem with code, not with
commercial software.

In this case, the mesh keeps topology while deforming. If a big deformation
occurs, will the deformed mesh become very thin and long? If so, mesh update
is neccessary?
I do not know how to implement mesh update now. Would you please tell me if
mesh update is possible or not? Is it very hard?

I collected many papers and read them. I only roughly know what will be
involved if I want to implement the parachute simulation. Now I am doing
something to see if it is doable for me with my capability.

Thanks for your help!

Zhan

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From: "Murtazo Nazarov" <[email-masked]>
Date: Wed, 13 Feb 2008 09:43:37 +0100 (CET)

> mesh update is possible or not? Is it very hard?

Yes, it is possible. The mesh update or smoothing is already implemented
in unicorn. The only thing you need, to call mesh.smooth(); after
deformation. It will help you to rearrange the mesh according mesh
quality.

> something to see if it is doable for me with my capability.

Good luck!

/murtazo

> Thanks for your help!
>
> Zhan
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> Unicorn-dev mailing list
> [email-masked]
> http://fenics.org/mailman/listinfo/unicorn-dev
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From: "Johan Hoffman" <[email-masked]>
Date: Wed, 13 Feb 2008 09:59:53 +0100 (MET)

Hi,

> This is exciting for me. Finally I can run a FSI problem with code, not

Good to hear that you enjoy this!

> mesh update is possible or not? Is it very hard?

We currently have as you see "mesh smoothing" that keeps topology while
maximizing quality by moving nodes. If you mean by "mesh update"
"remeshing", that is locally/globally generating a new mesh, this is not
yet implemented. Local remeshing is (as far as I know) an open problem,
but you may use a package for complete global remeshing (tetgen, for
example). Although this is not so far incorporated in Unicorn. What you
have today in Unicorn is: mesh smoothing, and mesh refinement/coarsening
(in Dolfin).

> something to see if it is doable for me with my capability.

I do not know your time frame, but you are considering a very challenging
problem. I would say that the fully inflated parachute may be possible
depending on your computing resources, but the deformed parachute at
landing seems being the capacity of Unicorn the coming months.

Good luck!

/Johan