I found that I can only set X-axis as axis-type boundary condition for axisymmetric solver. Otherwise, there is error as "non-positive cell area". Is that true or this error can be prevented by using other mesh or something else. It will be very inconvenient since my flow pipe is vertical. All the simulation/plot will be rotated 90 degree. Just a beginner in Fluent, please help me. Thanks a lot.

If you the axi-symmetric solver, the axis of your system has to be the x-axis of your system of coordinate.

If you have a vertical pipe to model, just create the mesh making the pipe axis lay on the x-axis and set gravity along x-axis equal to -9.81.

If you want to visualize contours and vectors, you can rotate the image using the Display -> View -> Camera, and saving the new view with a new name.

Hi

ap