overwrite temperature field using usrsrc
 

Hello, I know if I want to overwrite a source code, I should use USRSRC.f by making ICALL=2. Here I want to overwrite temperature to a constant value at every time step for an almost "stagnant" bulk region. I think I have to do it through manipulating equation of H but I only have a vague idea of how to, e.g. Cp*T*???. Can someone give me a suggestion?? Thank you heaps in advance. p.s. I am using CFX4.4.