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-   -   dynamicMesh - move surface due to velocity/pressure (https://www.cfd-online.com/Forums/openfoam-solving/143536-dynamicmesh-move-surface-due-velocity-pressure.html)

Tobi October 27, 2014 09:02

dynamicMesh - move surface due to velocity/pressure
 
1 Attachment(s)
Hi all,

I have a question and hope that someone can help me.
The problem is very easy and we want to extend this to use it for our project.

In the attachment there is a pipe (2d). The pipe is closed and there is a fluid inside. During cooling the density is changing and therefor the outer surface of the cylinder should move inside due to pressure force. The question at the moment:

  • which moving solver is good for that
  • some links about the stuff is working would be nice
  • maybe there is already some project on that topic - if you know it please let me know
You are welcomed if you can give me any hints about that topic.

Kind regards
Tobi

ssss October 27, 2014 09:32

Are you meaning that the mesh should deform as an elastic problem? Or that your complete mesh should move?

Tobi October 27, 2014 10:04

1 Attachment(s)
Hello and thanks for your replay.
In the attachment you can find further information.

Description of the PDF

  • At the top you can see the fluid stored in a tank or what ever (T1, and rho1)
  • Due to gravity the fluid will move through the gap which is cooled
  • Hence the fluid cools down it changes the density (T2, rho2)
  • Therefor shrinkage of the volume of the fluid will occure (rho = m/V and mass conservation)
  • Looking to the left draft you can see a static mesh where you have the interface between fluid and air entrapment
  • We want to change the mesh to that curvature the fluid will get while cooling (see picture on the right)




  • There are several options that can be checked out:
  • Moving only the first cell till it reaches a defined value and then delete those cells
  • Moving the outer points of the surface and due to the changed position move the internal mesh too
Would be nice if someone can give me more information, lectures, projects etc.

Kind regards
Tobi

ssss October 30, 2014 06:23

Hi Tobi,

You're work is far beyond my knowledge, my only concern about this is that you should track the liquid fraction in the cells, once it reaches a desired level, you should delete it or at least modify it so that \vec n = \dfrac{\nabla \gamma}{\mid \nabla \gamma \mid}.

Other problem would be that the boundary patch will change of cells.

I will post this so that your thread goes to the front.

Tobi October 30, 2014 07:38

Hi,

at the moment I made a new solver which moves the mesh due to density changing. This density changes due to temperature and the mass is conserved. Everything is working fine and I will go on with 3d mesh now and then to some curved surfaces.

wyldckat November 1, 2014 14:18

Quick answer/suggestion: http://openfoamwiki.net/index.php/Co...solidMechanics


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