RZ Coordinate Mesh

[Chris Lee]

Dear MOOSE users,

I'm trying to model a cylindrical pore through a material using rz coordinates. I have created a 3d mesh of my system, however when I try to run my application I get the following error message:

An RZ coordinate system was requested for subdomain 0 which contains 3D elements.

I assume that I have to convert my mesh in some way but I've not been able to find any examples for rz coordinates being used with a file mesh.

Any help would be greatly appreciated.

Kind regards,
Chris

[Chris Green]

Hi Chris,

I'm not sure that I'm visualising this properly, but using the RZ coord system rotates the mesh about the axis of symmetry, so the mesh can only be 1D or 2D. The 2D mesh rotated about an axis makes a 3D cylindrical mesh.

Is your 3D mesh a simple cylinder already? If so, you could probably just run the problem as is.

Cheers,

Chris

[Chris Lee]

Hi Chris,

More specifically my mesh is a block with a cylindrical hole through it and I'm trying to model the block. The block should be symmetrical about the axis of the pore.

Now that I've typed that out I think I can reduce my mesh to a 2d plane with a circular hole, however how would I define the size of the z direction? Would it be something like setting nz and zmax in the mesh block in the input file?

Kind regards,
Chris

[Chris Green]

I've done something like this to make a symmetric mesh with a hole in the middle (to represent a well):

[Mesh]

  type = GeneratedMesh

  dim = 2

  xmin = 0.1

  xmax = 1000

  ymin = 0

  ymax = 100

  nx = 100

  ny = 10

[]

[Problem]

  type = FEProblem

  coord_type = rz

  rz_coord_axis = y

[]

This takes a 2D plane and rotates it about the y axis, so I have a cylindrical mesh with a hole of radius 0.1 in the middle, 100 elements in the radial direction and 10 in the vertical direction.

From memory, if you output this to an exodus file, it only looks like the 2D plane - all of the rotation is done internally in MOOSE, so you might have to rotate the results to make it look like a cylinder.

I haven't tried using a file mesh, but I presume that if you use a 2D mesh that it should just work.

Cheers,

Chris

[Chris Lee]

Hi Chris,

Thanks! It appears to be working.

Kind regards,
Chris