Natural Convection Inside Square Cavity
 

I need help to write dimensionless temperature as field function star ccm+ having equation as dimensionless temperature (theta)=(T-Th)/(Th-Tc)

It is pretty simple. Just search in the tutorial '' user defined field function'' to see how to write a scalar property. ($Temperature-Tc)/(Th-Tc). If you do not have the values of Th and Tc then you need to 1- go to derived parts, make two points, one in the location of hot and the other at cold.
2- go to reports and make two reports for the two points ( function will be temperature).
3- go to tools/field functions/report... to see what is the name of the field functions already exist for the two reports.
Then insert the name of the field functions with a prefix of $.
good luck