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-   -   salome, openfoam and moving mesh (http://www.cfd-online.com/Forums/openfoam-solving/68601-salome-openfoam-moving-mesh.html)

prhlava September 25, 2009 04:32

salome, openfoam and moving mesh
 
Hello,

(all of this is from a beginner to OpenFOAM /and/ CFD)

First, thank you for making the OpenFOAM software available, this gives people like me a chance to start with CFD.

So far I have used simpleFoam to simulate not so simple flow in 3D (for learning purposes) and it works and the results look OK. The geometry was drawn in Salome (exported) and imported to OpenFOAM.

The /real/ problem I would like to simulate is a kind of pump which involves simulating a moving mesh. But at the moment I am really stuck with this. The geometry is not quite simple but I have managed to draw all of it in Salome - it is basically a pipe (1 mesh) with a "solid block" inside (2nd mesh, this one moves and the movement would be prescribed i.e. not dependent on the solution of CFD equations, only time dependent). The topology of the problem does not change.

I know enough (of Salome) to be able to create the pipe mesh, it's boundaries + internal mesh, and the moving mesh (and it's boundaries). What I cannot grok is how to create the case (for openFOAM) with the meshes exported from salome and make one move. Also, the solid block moves within the internal mesh of the pipe (where the flow is solved), how do I model this (obviously the flow should be calculated only outside of the solid block).

I looked at the movingCone example in tutorials, but I think it does not directly apply to Salome->moving-mesh->OpenFOAM kind of thing.

Any pointers gratefully appreciated, because at the moment I cannot move forward (do not even know how to start with this kind of simulation).

I am using OpenFOAM 1.6 and salome 5.1.2.

Kind regards, Vlad

chbenz September 28, 2009 12:52

hi vladimir,

i think the tutorial case movingConde should be a good start, even if you excluded it.
What role plays the second mesh?

Christof

prhlava September 29, 2009 04:13

Hello Christof,

Thank you for replying, maybe I was too quick in dismissing the movingCone case. Looks like I will have to start learning the blockMesh method of doing geometry (and do away with salome for this kind of thing). (but if anyone knows how to do this with using salome, I would still like to know)

I am trying to research/design a way of pumping liquid/air which I have not seen yet, the 2nd mesh does the pumping (well, /if/ it works).

Kind regards,

Vlad

chbenz September 29, 2009 04:23

Hi,

first have a look in the user guide. this is a good way to start with OF.
For your mesh: you only have to mesh the fluid volume. if your second "mesh" is a piston, that move through the fluid domain, you dont have to mesh it.

Christof

prhlava September 29, 2009 04:30

Quote:

Originally Posted by chbenz (Post 230799)
Hi,

first have a look in the user guide. this is a good way to start with OF.
For your mesh: you only have to mesh the fluid volume. if your second "mesh" is a piston, that move through the fluid domain, you dont have to mesh it.

Christof

Cheers, this pointer (not meshing the moving geometry) is really useful.

(me, going back to user guide).

Vlad

navier-stokes November 6, 2009 05:26

Hi Vlad!
For a first idea on how to make a moving mesh look at this post http://www.cfd-online.com/Forums/ope...erdymfoam.html.
If you like, I can send you my little "pump".

paulo November 7, 2009 11:34

Quote:

Originally Posted by prhlava (Post 230798)
Hello Christof,

Thank you for replying, maybe I was too quick in dismissing the movingCone case. Looks like I will have to start learning the blockMesh method of doing geometry (and do away with salome for this kind of thing). (but if anyone knows how to do this with using salome, I would still like to know)

I am trying to research/design a way of pumping liquid/air which I have not seen yet, the 2nd mesh does the pumping (well, /if/ it works).

Kind regards,

Vlad

Hello Vlad,

You don't have to give up Salome. To have your mesh read into OF, export it using the unv format and use the ideasUnvToFoam (i think this is the name) application. You wil have your mesh imported in a folder named by a number.

Remember to run the application inside the case folder (you can also place the unv file there). It will look for you controlDict.

Best Regards,

Paulo Rocha

prhlava November 9, 2009 09:55

cheers!
 
Quote:

Originally Posted by navier-stokes (Post 235317)
Hi Vlad!
For a first idea on how to make a moving mesh look at this post http://www.cfd-online.com/Forums/ope...erdymfoam.html.
If you like, I can send you my little "pump".

Just downloaded the case, I am about to try it out.

Kind regards,

Vladimir

prhlava November 9, 2009 09:59

Quote:

Originally Posted by paulo (Post 235431)
Hello Vlad,

You don't have to give up Salome. To have your mesh read into OF, export it using the unv format and use the ideasUnvToFoam (i think this is the name) application. You wil have your mesh imported in a folder named by a number.

Remember to run the application inside the case folder (you can also place the unv file there). It will look for you controlDict.

Best Regards,

Paulo Rocha

Thanks for the reply, I can sort of do static mesh using salome (e.g. joint pipes and such) and simulate that in open-foam, but have/had trouble making e.g. enclosed "box" with one object moving inside it.

Kind regards,

Vladimir


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