Learning Forum

[cirne]

Hello,

I am a master student using Fluent for my thesis and I run into some issues when setting periodic boundary conditions, I have checked the forum and although I have seen some related questions I have not found my same question.

I have an axisymmetric body and domain and in order to reduce the computational needs I am simulating one quarter of the overall volume but instead of using symmetry boundary condition on the vertical and horizontal cuts I want to use periodic boundary conditions since I will need the body to rotate/spin later on. I have included some screenshots of the mesh.

However, when I try to set up the boundary I get the error “Error: Failed to make zones periodic. Error Object: #f”

I have the same number of elements in both faces, I have included the mesh check below and the TUI commands used. The faces are id 6 and 7.

Does anyone know how to solve this issue?

Cheers,

Zone sizes on domain 1:
  449824 hexahedral cells, zone  2.
 1316302 quadrilateral interior faces, zone  1.
    4736 quadrilateral wall faces, zone  5.
   29618 quadrilateral symmetry faces, zone  6.
   29618 quadrilateral symmetry faces, zone  7.
    2368 quadrilateral wall faces, zone  8.
  483413 nodes.
mesh/mod

/mesh/modify-zones> mp
Periodic zone [()] 6
Shadow zone [()] 7
Rotationally periodic? (if no, translationally) [yes] yes
Create periodic zones? [yes] yes

Error: Failed to make zones periodic.
Error Object: #f

[cirne]

I forgot to attach the images, here they are:

 

[Karthik Remella]

Are the number of faces on zone 6 and 7 the same? Do they have one to one mapping?

If this is not the case, you might not be able to create them as periodic. Could you please check this?

Thanks.

Karthik

[cs437]

I also have this problem since Periodic zone needs 2 mirror faces. That is why zone filled in Periodic and zoned filled in shadows are same zone. By the way, how to know where the shadow zone is? To not being the same faces zone, do name selection in meshing step should be done each face separately in order to get separate boundary condition ( I combined 2-mirror faces to be one boundary condition in order to define this periodic), but it doesn't work. Please suggest.

 

If this is MRF, does periodic bc's need to apply both inner and outer domain at the side?

[cirne]

Thanks for the suggestion Kremella.

I do not know what one to one mapping is, how can I check that? On the other hand, as far as I can check, they do have the same number of faces (29618 quadrilateral symmetry faces both):