2D pipeline
 

Hi
I'm doing CFD, fluent

How I know that 2D pipeline I draw it's a pipeline.

How ansys define this?

Thanx in advance

I mean how ansys will know that a pipeline in 2D not rectangle.

You should model half the pipe and your boundary condition will be wall and axisymmetric. Then you will have your 2d round pipe

When the pipe changes its direction, it is assumed that it is not rectangle pipe.