Subject: [Unicorn-dev] no slip BC

From: Bartosz Sawicki <[email-masked]>
Date: Mon, 21 Jan 2008 19:55:21 +0100

Hello,

I've read on DOLFIN-dev mailing list that you have implementation of
no-slip boundary condition. I'm very interested in application of such
BC, so I pull Unicord code from repository and analyse it.

I'm not familiar with Unicorn, so I it is troublesome to find location
of code responsible for no-slip BC. Only I found is:
/ucsolver/icns/bench2D/main.cpp
But this is very specific solution for cylinder.

Do I missed something? Is somewhere more general code?

My application is not connected with mechanics. I'm solving
electromagnetical problem, but with very similar type of BC.
On my problem I need to set zero Dirichlet BC only to the tangential
components of vector field, normal component should have no fixation.

I rewrite old application into Dolfin, so I'm quite conscious problems
of normal vector in the node (average over neighbour facets), local
coordination system mapping, and so on.

regards
BArtosz Sawicki

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From: Murtazo Nazarov <[email-masked]>
Date: Mon, 21 Jan 2008 20:05:36 +0100

> coordination system mapping, and so on.
Hi,

I think you mean slip BC? The no-slip implementation can be found from
src/kernel/fem in DOLFIN. If you mean slip BC it is not yet available 
with this
version of Unicorn.

/murtazo

---

From: Bartosz Sawicki <[email-masked]>
Date: Mon, 21 Jan 2008 20:59:52 +0100

> src/kernel/fem in DOLFIN. If you mean slip BC it is not yet available 

My applicatiom has nothing similar with word 'slip', which is 
mechanical. I have to set different Dirichlet BC for tangential and 
normal compoments of the vector function. Simple DirichletBC class from 
src/kernel/fem/ can't manage such task.
As far as I understand my problem is similar to slip condition with zero 
for tangential components. Or maybe I am wrong?

regrd.
BArtosz

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From: "Murtazo Nazarov" <[email-masked]>
Date: Mon, 21 Jan 2008 21:55:51 +0100 (CET)

> for tangential components. Or maybe I am wrong?

Ok. Then you can probably use the slip implementation. In which we put
normal component to be zero. But, you can modify the code to handle your
problem. The code works for the old DOLFIN version, now I am working to
get it working for the latest one. It will be next week I think.

/murtazo

---

From: Bartosz Sawicki <[email-masked]>
Date: Mon, 21 Jan 2008 22:05:32 +0100

> get it working for the latest one. It will be next week I think.

Great :) !
So I will wait, and check repository next week.
Thanks a lot for your answers.

regrd.
BArtosz