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Old   June 28, 2013, 17:59
Default moving wall
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Yu CAO
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Hi
I am wondering if there is a method to move the boundary at a specified speed and change the mesh automatically in openFoam. I mean the most side wall move, not a solid body in liquid. In that case, the whole simulation domain would change, not partial domain.(something like piston moving in the vessel). I know a solver named icoDymFoam could address body moving in liquid issues, but I don't know if it could be used to simulate the situation I described above. if so, how to. If not, if there exists any other methods to fullfill it.
Thank you.
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Old   July 5, 2013, 04:28
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Hi,

do you know this tutorial?
Code:
OpenFOAM-2.2.x/tutorials/incompressible/pimpleDyMFoam/movingCone
Is that what you are looking for?

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Old   July 5, 2013, 06:36
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Quote:
Originally Posted by nlinder View Post
Hi,

do you know this tutorial?
Code:
OpenFOAM-2.2.x/tutorials/incompressible/pimpleDyMFoam/movingCone
Is that what you are looking for?

Greetings
Nicklas
Yes, I know this,but this is a solide body in the liquid. Not what I want. I need, for example, the inlet boundary moving.
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Old   July 5, 2013, 07:14
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Yes, but don't you just need to apply the pointMotionU to whatever boundary you want?
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Old   July 5, 2013, 08:30
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Quote:
Originally Posted by nlinder View Post
Yes, but don't you just need to apply the pointMotionU to whatever boundary you want?
Yes,though the boundary moved, the result is not correct. Have you ever tried before? e.g. I want no body in liquid and the most left boundary move at a specified speed? In addition, this case is dynamic mesh with cell compressed, how about with layer addition and removal?
Thanks.
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Old   July 5, 2013, 08:46
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I use this procedure to move a boundary. Basically I compress the fluid between two plates. My moving boundary is a solid, but not embedded in fluid. I just thought that it would work the same way for any other boundary. I don't know what boundaries you set therefore I cannot say if it will work for your case. Also if you say the results are not correct it's difficult to help.. You need to be more precise..

Greetings
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Old   July 5, 2013, 12:16
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Quote:
Originally Posted by nlinder View Post
I use this procedure to move a boundary. Basically I compress the fluid between two plates. My moving boundary is a solid, but not embedded in fluid. I just thought that it would work the same way for any other boundary. I don't know what boundaries you set therefore I cannot say if it will work for your case. Also if you say the results are not correct it's difficult to help.. You need to be more precise..

Greetings
Would you please have a look at it and see anything wrong in it?
In addition, I am wondering how to specified the motion of the boundary and is there a way to address boundary wall motion with layer addition and removal way?
Thanks.
Attached Files
File Type: zip movingBoundary.zip (9.0 KB, 16 views)
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Old   July 9, 2013, 10:49
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Hi cctv,

I had a look at your case, but I do not understand what you try to do.

It is a 2D case. We have 3 boundaries:
- movingWall
- fixedWall
- farField

But if I got you right from your previous posts, you don't want to move a wall, correct? So maybe you can give me a hint what each boundary is plant to do?

Thanks
Nicklas
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Old   July 10, 2013, 04:15
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Quote:
Originally Posted by nlinder View Post
Hi cctv,

I had a look at your case, but I do not understand what you try to do.

It is a 2D case. We have 3 boundaries:
- movingWall
- fixedWall
- farField

But if I got you right from your previous posts, you don't want to move a wall, correct? So maybe you can give me a hint what each boundary is plant to do?

Thanks
Nicklas
Hi Nicklas, I do want to move a wall, I just want to simulate a case similar to a piston moving in a vessel. as the liquid is incompressible, the fixedWall's U boundary condition, used as the outlet, is inletOutlet. Thank you.
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Old   July 10, 2013, 04:36
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First problem was a typo in the constant/dynamicMeshDict file

Code:
"libfvMotionSolvers.so"
correcting this, you can go on correcting the wrong/missing parts of your setup (fvSolution is missing some entries, fvSchemes as well and the pointMotion should be a vector, not a scalar). Make sure you set a totalPressure BC for the deforming walls and set the other BCs as desired (outlet or whatever).

Greetings
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Old   July 10, 2013, 05:26
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Quote:
Originally Posted by nlinder View Post
First problem was a typo in the constant/dynamicMeshDict file

Code:
"libfvMotionSolvers.so"
correcting this, you can go on correcting the wrong/missing parts of your setup (fvSolution is missing some entries, fvSchemes as well and the pointMotion should be a vector, not a scalar). Make sure you set a totalPressure BC for the deforming walls and set the other BCs as desired (outlet or whatever).

Greetings
Nicklas
Thank you for your reply. there is no typo in it because what I send you is a case run in 1.6-ext. what you said is how to run in 2.1.0 or even higher version. however ,I could try it in this version. What's more, do you know how to move the wall with layer addition and removal methods? just like movingbodysolver. Thanks.
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Old   July 10, 2013, 06:54
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Would have been easier if you told that before...

This is what I got as a "result":
https://dl.dropboxusercontent.com/u/587565/ani.gif
(2.2.x)

About layer addition or removal I don't know much. I only used dynamicMeshRefinenemt for adding or removing cells. I don't know if the combination works as well..

Have fun
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Old   July 10, 2013, 13:24
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Quote:
Originally Posted by nlinder View Post
Would have been easier if you told that before...

This is what I got as a "result":
https://dl.dropboxusercontent.com/u/587565/ani.gif
(2.2.x)

About layer addition or removal I don't know much. I only used dynamicMeshRefinenemt for adding or removing cells. I don't know if the combination works as well..

Have fun
Thank you very much. Could you tell me how to add or remove cells? and where is the code they map the old field into the new field?
Good luck
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Old   July 10, 2013, 15:11
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This may be of to interest to you:

engineMesh with layered addition removal

You may have an easier time making things work as you are using 1.6-ext (I assume from previous posts). There may be a movingConeTopo mesh class; if not you will need to make your own.
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