What kind of motion simulation you would like to do in NX? I have one very simple motion simulation example in my profile, made with NX.
There are some videos about Motion Analysis.
It depends on the type of CFD analysis you want to do..Here is a simple one which I have downloaded.
AttachmentsAdvanced_flow_analysis_in_Unigraphics.mp4, 9.96 MB
Don't get offended but that CFD analysis is totally wrong.
If you create inlet flow to the pipe face itself it doesn't simulate flow inside the pipe but in the pipe material (aluminum/steel etc) instead which obviously wasn't what you intended to do?
If you have the pipe modeled, you have to create another solid inside the pipe to represent the flowing material (gas, liquid etc) and in the simulation environment define it as "Fluid Domain". This is how you can simulate flowing material inside the pipe like you though to.
Another solution is to model the flowing material only which is good for flow simulation where heat is not considered. From the pipe model this can be created by deleting the outer faces of the pipe and the ends which will leave you with the inner faces of the pipe only, then create Bounding Planes to the ends of the sheet model and sew them all together to create a solid which now represents the air/liquid volume inside the pipe.
And by the way this question was about motion simulation, not CFD which is a whole another thing but I hope someone finds this useful anyway.