CFD Online Discussion Forums

CFD Online Discussion Forums (
-   FLUENT (
-   -   Convergence issue in Fluent (

dibs87jg April 20, 2011 04:52

Convergence issue in Fluent

I am having some problems finding convergence with my case of study. I am studying the flows in between the blades of a high speed centrifugal pump impeller.

I cannot make the residuals go any lower after 500 hundred iterations approx. It seems like they are stuck.

The order of my residuals are:
  • Energy ~10-5
  • X, Y, Z, Velocity ~10-4
  • Continuity, k and epsilon ~10-2

I monitor the mass flow rate at the outlet and it gets stable after 500 iterations so it seems like I reached convergence but my lab mates told me I need at least to reach 10-3

I’ve looked at the results and everything seems to be okay. Tip speed, Inlet/outlet velocity, static and total pressure, mass flow rate, velocity vectors…

Can I trust these results? Or how can I improve the residuals? I've done many different tries... It weirds me out that which such less iterations I could get some good results in something that theoretically seems complicated… I’ve done some other simpler studies with Fluent and it required me many more iterations.

Any suggestions?

All times are GMT -4. The time now is 06:29.