Initializing of solutions
 

Dear friends, I have a tank with recycle, and I am studying the mixing time. For that I am using temperature to define my mixing criterion. I want the system first to acquire the fully developed flow as far as the velocity field is concerned. After the flow field is fully developed, I want to define a small volume inside the total tank volume as having a separate temperature (e.g. temperature in this small zone is 400 K, while in the rest of the zone it is 300 K). Taking the time of assigning this temperature distribution as zero, I want to monitor the transient temperature distribution in the tank. My problem is: "How do I initialize this temperature distribution after getting the fully developed flow?", because I cannot initialize only the temperature distribution and keep the velocity field as solved in previous time step,....or CAN WE???