FLUENT 6.1: How to avoid unphysical low/high temperatures near shell conduction zones
For some cases, turning on the planar-conduction model results in unphysical temperatures
at cells near several planar conduction zones. At those cells, the temperature hits
the specified upper and lower limits.
The resolution is to turn off the secondary-temperature-gradients in the shell conduction zones. This is done by typing the following Scheme command in the FLUENT text window:
(rpsetvar 'temperature/shell-secondary-gradient? #f)
The default is true.
This will decrease the accuracy of the diffusive flux computation in the shell conduction zone to first order, but should significantly improve the stability of the temperature field.
This problem has been fixed in FLUENT 6.2 and this workaround is no longer necessary.