6.8.4 Creating Conformal Periodic Zones

ANSYS FLUENT allows you to set up periodic boundaries using either conformal or non-conformal periodic zones. You can assign periodicity to your mesh by coupling a pair of face zones. If the two zones have identical node and face distributions, you can create a conformal periodic zone. If the two zones are not identical at the boundaries within a specified tolerance, then you can create a periodic zone at a non-conformal mesh interface (Section  6.4).

Remember to save a new case file (and a data file, if data exist) after creating or slitting a periodic boundary.

To create conformal periodic boundaries, you will use the mesh/modify-zones/
make-periodic text command.

mesh $\rightarrow$ modify-zones $\rightarrow$ make-periodic

You will need to specify the two face zones that will comprise the periodic pair (you can enter their full names or just their IDs), and indicate whether they are rotationally or translationally periodic. The order in which you specify the periodic zone and its matching shadow zone is not significant.

/mesh/modify-zones> make-periodic

Periodic zone [()] 1

Shadow zone [()] 4

Rotational periodic? (if no, translational) [yes] n

Create periodic zones? [yes] yes

Auto detect translation vector? [yes] yes


  computed translation deltas: -2.000000 -2.000000 
  all 10 faces matched for zones 1 and 4.

  zone 4 deleted

  created periodic zones.

When you create a conformal periodic boundary, the solver will check to see if the faces on the selected zones "match'' (i.e., whether or not the nodes on corresponding faces are coincident). The matching tolerance for a face is a fraction of the minimum edge length of the face. If the periodic boundary creation fails, you can change the matching tolerance using the mesh/modify-zones/matching-tolerance text command, but it should not exceed 0.5 or you may match up the periodic zones incorrectly and corrupt the mesh.

mesh $\rightarrow$ modify-zones $\rightarrow$ matching-tolerance

For information about creating non-conformal periodic boundaries, see Section  6.4.4.