Learning Forum

[rglsj]

Hello everyone!nI believe this one is already answered a hundred times but I'm a new user of Fluent, and I can't figure out how to write UDF for axisymmetric velocity profile at inlet (e.g. parabolic profile). I don't understand how to define coordinates, are they same as 2 planar (so x is radial coordinate and y is radial) or is there some other way of signing coordinates.nThank you!n

[Kalyan Goparaju]

Hello, nIs there a specific reason for you to be using a UDF? If not, I strongly recommend using the Expressions featured to setup the profile. Its relatively a lot easier. Please do look up the user's guide for more information regarding Expressions.nThanks,nKalyann

[rglsj]

Hey Kalyan, thanks for the answer!nI just want to learn how to use it, I'm not doing any specific project, but learning how to use UDF codes. I'm considering a basic flow in a pipe. Most cases in Fluent verification materials use fully developed inlet velocity (and also turbulence) profiles so for that it would be nice to know how to write those codes.n

[Kalyan Goparaju]

Fair enough. To answer your question, yes, you would have to write the UDF as if it were a planar 2D case. Once you have the UDF compiled and loaded, I recommend running 1 iteration and checking if the flowfield is being initialized as intended. n

[rglsj]

Thanks a lot!n