KNOWN ISSUE: Heat Transfer solutions may not be exactly periodic
Heat transfer solutions on wall boundaries that span a periodic section may not be exactly periodic, even if the specified conditions on that boundary are exactly periodic. For example, the variable Wall Heat Flux, when plotted on the periodic edges of a wall boundary that intersects both periodic boundaries, may show significant discrepancies.
This issue is caused by the differences in mesh location at which certain variables are evaluated during the solution process (for example, integration points and face centres). This inconsistency can can cause slight differences in the solved variables (e.g. Temperature) on periodic boundaries, and this can lead to larger differences when derived variables (such as Wall Heat Flux) are evaluated. These differences are similar to discretization errors, and should diminish as the mesh is refined.
No workaround is currently available.
ANSYS CFX Release 12.1. A custom executable for ANSYS CFX Release 12.0 is available on request. The fix can be enabled by setting the expert parameter 'use bip flux = t'.