Residuals-Ccontinuity
 

Hello dear all,

I am a newbie using ANSYS Fluent. I have a 3D model which's inlet is velocity inlet and outlet is is pressure outlet. I tried to solve it for three different mesh models and for each I got different solutions. I enter all values same, only mesh is different. I am also employing a formula, so it is interesting that the one with more fluctuations in continuity residual gets closer to the formula output. I am attaching residuals to this thread, I would be really happy if anyone let me know which one is more correct.

Thank you beforehand. Attachment 75556

Attachment 75557

Attachment 75558

Residuals
 

Residuals alone are not good indicators of convergence. You have to monitor some other quantity, such as pressure at inlet, to measure convergence.

Convergence does not imply accuracy, only that the field is converged for a given set of conditions.

So, better would be to set a few monitors in all cases and then observe how much do they change over iterations and from case to case.