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-   -   Merging Meshes (http://www.cfd-online.com/Forums/fluent/27487-merging-meshes.html)

Matteo Giacobello. February 9, 2000 23:43

Merging Meshes
 
Hi, I would be very greatful if anyone has any suggestions on the following topic.

I have been trying to run fluent using using a merged mesh. I have tried merging two meshs using TGrid and the command line operation: tfilter tmerge3d mesh1.msh mesh2.msh mesh3.msh

The meshes I am trying to merge come together along one edge of a curved surface. One mesh consists of tetra elements. The other consists of tetra and prism elements. The result is that when the meshes are merged I have some tetra elements butting up to prism elements along the edge where the meshes come together.

Once the meshes are combined and read into fluent I specify an interface between the meshed. Fluent subsequently creates several new entities called 'wall- '. I have found that if there are zero elements in these entities fluent runs okay. However as soon as there are a few elemnts in these entities fluent complains that the pressure and viscosity limit have been exceeded in a few cells in the mesh and subsequently crashes. Based on these results I have come to the conclusion that I should always be aiming to have no cells in the 'wall-' entities.

When there are cells in these 'wall-' entities they always occur where the prisms butt-up againts the tetra elements.

In order to get rid of the cells in the 'wall-' entities I have tried varying the element size at the interface and recreating the interface.

Any suggestion on how I could get over this problem?

Thanks

Matteo Giacobello. AMRL-DSTO Australia

Kai Kang February 16, 2000 10:22

Re: Merging Meshes
 
are you using the moving reference frame, like moving the mesh, during the computation?

the Wall- are generated automatically if the two interfaces are not conformed.

Those viscosity limits are just artificial limits, you can set it in Fluent/Control/Limits menu. It may have something to do with you IC/BCs.


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