Hi, I am trying to test a supersonic flow in a simple divergent duct. Is it possible to set velocity inlets or does it have to be pressure inlets?. Something else, any advice about setting the reference pressure on CFX? Thanks for your time.

you can set velocity in the inlet instead of pressure inlet... the way to set the flow to be supersonic is to choose 'total energy' option instead of 'thermal energy' when setting up the fluid model.