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Old   October 27, 2006, 07:53
Default Moving Nodes Again
  #1
jon
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I want to move nodes in a similar way to that of the junction box routine in the moving mesh valve tutorial. However I will only want to specify the node postitions at the boundary and let CFX remesh the rest.

The mesh files in the tutorial example seems very basic.

Just 3 columns, assume these are XYZ. Does the read file not need to have a node number or connectivity table? how does it know which node it is moving to what location?

Thanks
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Old   October 29, 2006, 16:46
Default Re: Moving Nodes Again
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Glenn Horrocks
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Hi,

You could use a CEL fortran routine to define the node positions on the boundary and use the internal mesh movement smoothing routine to generate the internal node locations.

Glenn Horrocks
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Old   October 30, 2006, 09:44
Default Re: Moving Nodes Again
  #3
Robin
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These routines assume the nodes are listed in the same order for each sequence of meshes. The first mesh must be identical to the one in the def file and it locates the nodes by comparing coordinates. After that, it simply uses the difference between the meshes to compute the displacement of the node.

If you only need to move a boundary, try using a CEL expression of User Fortran routine instead. You may still need the junction box routine to load the sequence of node placements. Note that CFX does not do any remeshing, it simply moves the nodes within the domain. It does this by solving the mesh displacements as a diffusion problem, with the specified boundary displacements being the boundary condition to the diffusion equations. If your motion causes the mesh to fold, the solver will shut down and write a results file which you can use to interpolate onto a new mesh and start again.

Regards, Robin
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Old   October 30, 2006, 09:49
Default Re: Moving Nodes Again
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jon
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Thanks Robin, really helpful. I do only need to move a boundary but it does not stick to a predescribed function etc. Different parts are going to deform at different rates etc. Deformation should be relatively small so think think the moving mesh within CFX will be ok. I thin kthat means I will have to use the junction box. Jon
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Old   October 30, 2006, 10:28
Default Re: Moving Nodes Again
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Robin
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How is the motion determined? You might be able to do it entirely with CEL.
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Old   October 30, 2006, 10:37
Default Re: Moving Nodes Again
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jon
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I am doing an FSI simulation with an external structural solver. The application is yacht sail hence the non unoform displacement.

My structural solver will output a file containing the new XYZ locations of the nodes on the sail surface, and was then somehow going to use a junction box to update the nodes.

Any advice would be appreciated as have never done anything using junction boxs or like before. JOn
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Old   October 30, 2006, 10:43
Default Re: Moving Nodes Again
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Robin
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This is too advanced to get into in the forum. I suggest contacting ANSYS for help.

-Robin
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Old   December 1, 2006, 13:14
Default Re: Moving Nodes Again
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Joe
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Interesting
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