Intensity and hydraulic diameter
 

Hello.
I have a question about how to define in Fluent, intensity and hydraulic diameter of the inlet velocity condition.
The problem is that I have an input stream to a cylindrical duct which is initially laminar while then the duct narrows and the motion becomes turbulent. The hydraulic diameter that I use is that relating to the input of fluid, or that of the section where the flow becomes turbulent?
Thank you all.