Hello My friends , I want to deal with a nozzle in an unsteady flow , what methodology should I use in your opinion to solve it using Computational Fluid Dynamics and using Fluent software .

Thanks in advance

Johannes, I have no experience with Fluent, but I will not let that stop me. Check out Anderson's Computational Fluid Dynamics, section 7.4.

I have done this for a jetpump using STAR-CD. In that case I benchmarked my model against steady state data (see the validation cases for a nozzle at http://www.grc.nasa.gov/WWW/wind/valid/homepage.html) and then set the transient input using a table.

Good luck. Tom