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-   -   moveDynamicMesh for moving a patch (Tz and Ry) (http://www.cfd-online.com/Forums/openfoam/98503-movedynamicmesh-moving-patch-tz-ry.html)

bouclette March 12, 2012 16:40

moveDynamicMesh for moving a patch (Tz and Ry)
 
Hi All,

I am trying to obtain the equilibrium attitude of a floating object without having to use the interDyMFoam solver. I have no interest at all in the transient solutions.

I was hopping to make a script that moves my patch (not the whole domain) in order to match the mass and moments every n seconds in order to reach a steady state attitude after a few motion iterations.

I thought I could use the motion solver moveDynamicMesh but I haven't been successful at moving my patch in both translation and rotation at the same time.

I have tried some of the available patchFields in the pointDisplacement file but either couldn't figure the correct syntax to make them work or they do not seem to suit my needs. Couldn't find much in the tutorials neither as my case is a bit off the usual applications I think.

Has any of you got some tips and advises to give me in order to move a patch in a mesh?

Regards,

B.

Ralph M August 24, 2013 08:29

Ben,

You should think that OF at least would include a tool which would be able to modify the position of a patch with a simple rotate/translate command...however, so far I'm not able to find it! Any luck on your side yet?

Cheers,

Ralph

fredo490 August 25, 2013 07:29

OpenFoam has a mesh translation tool... It's quite undocumented but it is there.

For this problem, I wouldn't use a dynamic mesh but rather dynamic boundary conditions. The equilibrium of the object depends mainly of the pressure. You can use "groovyBC" which is able to modify a boundary condition depending of a measurement.

You can use the force on the object to modify the pressure. For example, if the force goes up, then the boundary condition lower the pressure. If the force goes down, the boundary condition rise the pressure. At the end, you get the equilibrium pressure and therefore the altitude ;)

Ralph M August 26, 2013 15:59

Dear Frédéric,

Thank you for you reply, I greatly appreciate your comments on this problem. However, one thing I didn't told you about is that I have a similar (more coarse) mesh with results (i.e. flow pattern) available. I'm looking forward to generate this fine mesh and then map the results from the coarse mesh on the fine mesh. For this mapping process I need to impose the motion of the ship in the new mesh.

So do you have any ideas how this mesh translation tool is called? I looked in the source code several times but without succes so far.

Regards,

Ralph


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