[denispansolin]

Hello everyone, I am trying to simulate turbulent compressible flow in a pipe with variable geometry (diffuser and nozzle). I am using air as the fluid (ideal gas). My mesh and geometry images are attached. The boundary conditions I have tried are:
1. Velocity inlet-pressure outlet
2. Pressure inlet-pressure outlet
3. mass flow rate inlet- pressure outlet
In all cases I am having same problem, that my flow (velocity) at the entrance of diffuser (exit from channel), the velocity contours goes up or down, not symmetric. ( I have attached the figure of the problem for better understanding). I am using coupled solver.
I am not able to figure out if its a mesh issue or somewhere I am missing something in setting up the problem.

It would be great if anyone can help me. Please.

Thank you.

[sufjanst]

Did you specify the right Rotation-Axis Direction in your Cell Zone Conditions -> <fluid> ?

It is set to Z = 1 by default, your rotation axis is at X = 1. That can have an effect on the solution depending on your Boundary Conditions.


Greets
sufjanst

[denispansolin]

Hey sufjanst I did what you said but I still have the same problem.