Sorry for the confusion. I am trying to model a pipe flow with a porous media using 2D axisymmetric. The interior in Fig 1 does not allow me to hook a udf for the species, therefore, I want to use the inlet-velocity boundary condition on the wall 2 (interior in figure 1) in figure 2 to model both the flow through the porous media and hook my species udf. By hooking the udf, it would allow me to see the concentration profile near the wall 2 in figure 2.

As I mentioned before, the flow out is the opposite of what the velocity inlet boundary condition wanted, therefore, the species udf would not be used. Ansys used the upstream cells to model it. I would like to know if there is a boundary condition or a way that allows me to hook both a velocity and species udf on a boundary.

Thank you!