I need help: Dynamic meshing with Polyhedral mesh

  • Last Post 12 May 2020
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YJKim posted this 12 May 2020

Hi ANSYS everyone!!

I have some problems and questions about dynamic mesh. Need your help please.


I made meshing with fluent meshing and, mesh type is polyhedral. For next, I want to moving bottom of cylinder and remeshing at the same time. So I compiled UDF and checked the dynamic mesh.

ANSYS user guide said that, it is recommended to use the diffusion method for polyhedral mesh, and CutCell zone remeshing method for 3D flow. In my case, my mesh is not tet and hexa so I just selected CutCell zone remeshing which is applied for all cell types.

So I checked that, and next ,moving piston(bottom) is selected for rigid body and partbody1(bottom of cylinder) is checked for deforming in dynamic mesh zones.

I think selection is right, but results failed everytime I attempted. I think it was not remeshed, it just lengthened like a pepero.

I don't know what is problem. I attached my case picture, please need your help...


 +I tried to attach some pictures, but error is popped up!  Without pictures, is it possible to give you a question? If it is hard to understand, I will try again. Thanks in advance!

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rwoolhou posted this 12 May 2020

There's a glitch somewhere so pictures tomorrow is fine: IT are on the case. 

I didn't think that poly meshes and moving mesh worked together, check the documentation for that. I know poly remeshing is being looked into, but again I'm not sure of the status as it's not an area I tend to work on.  Can you remesh with tets (available in Fluent Meshing) and read that mesh into the current set up? 

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YJKim posted this 12 May 2020

Thank you for a swift answer, and about picture problem.

I already remeshed all cell zone with tets, but skewness became extremely high and number of grid exceeded 512000. So I think I have a second option. How about making a mesh with poly for upper of cylinder, and a mesh with tets for bottom of cylinder where is dynamic mesh is applied?

I want to know if this method will work. I heard a bit it is possible to create the grid differently for the two regions with Boi(in fluent meshing). Is it ok to ask you about how to do this?