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-   -   gradually opening wall (http://www.cfd-online.com/Forums/openfoam-solving/109721-gradually-opening-wall.html)

immortality November 24, 2012 16:15

gradually opening wall
 
hello
I want to simulate a long channel you may assume closed end at right side but at the left side the wall move from rest at a constant velocity downward so that it opens to a constant stagnation pressure and stagnation temperature-that we know the values of them-environment that are greater than inside the channel.how can I model this gradually openning wall? should I mix groovyBC and mixed boundary conditions?how?or this can be done easier?

wyldckat November 25, 2012 07:18

1 Attachment(s)
Greetings ehsan,

Someone asked me a similar question a few weeks ago and I took a look at this today. An I saw your post due to some strange spammer that was going around posting some weird text...

Anyway, attached is an example "flexibleSideCube.tar.gz", based on an example case from the OpenFOAM bug tracker: http://www.openfoam.org/mantisbt/view.php?id=566.

The changes I've made were also based on one of examples that swak4Foam has for groovyBC: "Examples/groovyBC/movingConeDistorted/"

You simply need to run:
Code:

./Allrun
for it to do its magic. Keep in mind the changes I've made:
  1. I've used groovyBC for generating the necessary point displacements, which have to be gradual along X, since we want the left side to be fixed.
  2. I've had to add the "cellMotionUz" file, because without it only the top wall would move and the remaining mesh would stay the same.
  3. I've modified "dynamicMeshDict", so that it would distribute the cells a bit better. Look at the example in groovyBC for more ideas on the types of mesh diffusion there are!
  4. I've used moveDynamicMesh only, so the case is merely an example of dynamic mesh and is not prepared yet for using any other solver... except perhaps interDyMFoam, since I didn't modify several files from that other case from the bug tracker.


So as you should be able to figure out, this example only takes care of the dynamic mesh part, it does not show an example of boundary conditions to be used by a fluid solver.


Best regards,
Bruno

wyldckat December 1, 2012 08:34

I can't believe I forgot to attach the file... I was probably already very sleepy back then :(

Anyway, I've attached the missing file to the previous post.

immortality December 1, 2012 18:08

Thank you very much dear Bruno.I didn't find anything and thought may you have send the post by mistake or you mention to that link of debug.
thanks very much again.

immortality December 1, 2012 18:13

a question! what commands I should write if I dont want to use ./Allrun ?
thank you.

immortality December 1, 2012 18:23

I run that.that was really interesting.thank you.
a irrelevant question.how can use the functions of temperature properties of perfect gas in rhoCentralFoam?like Janaf tables?


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