[megacrout]

Hi everyone,

I am trying to simulate the flow of a gas through a pipe due to a pressure difference between inlet and outlet. I first did it using a 5°-element and wedge patches like suggested in the tutorial (user guide). This works great.

As I want to get in the end the entire shape (or at least a quarter of a pipe) and don´t want to compute too many normal vectors for the mirrorMesh function, I tried using other symmetries. But could not get any of them to work.
No matter what I try, I get a physically unjustified slow flow in the center of the pipe (where it should be the fastest). Even though this disappears as the steady state is reached, I´d like to get the transient situation right too.

Here are the geometries I tried:
- triangle (one corner set equal to another one) with one curved side
- square with one corner at a distance from the opposite corner equal to the two opposite side (i.e. radius) and its two sides curved
- square with a tiny (but not zero) face and a curved one (the opposite one), the two remaining faces being normal to each other

And the patch I tried for the axis or the face close to it (depending on the selected shape):

-empty
-wall (patchField slip)
-symmetryPlane

The curved face(s) remained as "wall" and the sides as "symmetryPlane".

I can´t show any code nor pictures of my problem (using 2 computers with no administrator access, internet on one, openFoam on the other one...) so let me know if you need further descriptions.

Thanks for your help.

Tibo