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-   -   Fluent- bad pressure contours and messages while calculating (http://www.cfd-online.com/Forums/fluent/96392-fluent-bad-pressure-contours-messages-while-calculating.html)

tom634 January 21, 2012 09:15

Fluent- bad pressure contours and messages while calculating
 
Hello,
I make compressor simulations. K-epsilon, pressure based, gauge pressure and initial pressure at inlet 1bar, pressure outlet 2,5bar, walls of blades rotating 16.000rad/s, maximum cell squish 0,802, maximum cell skewness 0,88, maximum aspect ratio 22,5. I receive results as on picture:
http://i.imgur.com/nQYFJ.png
I have underpressure, solution doesn't converge, I receive all the time while calculating "Reversed flow in xxx faces on pressure inlet yy. Reversed flow in zzz faces on pressure outlet tt. Turbulent viscosity limited to viscosity ratio of 1e+5 in vvvvvv cells." event after 3000 iterations. When I take density based, I receive "Divergence detected in AMG Solver: Coupled -> Decreasing coarsening group size! Increasing relaxation sweeps! Reducing Courant number."
How to edit Cell-Zone Conditions? I have only fluid in cell-zone conditions.
What is wrong and how to repair this?

tom634 January 22, 2012 10:19

What do you suggest to do with this case? Max skew size is 0.85.
http://i.imgur.com/azUUj.png

cartman February 1, 2012 08:50

how was your under-relaxtion factors?

tom634 February 1, 2012 13:19

Standard, I didn't change anything. Problem solved by manipulating limits of pressure and temperature.

hadi1984 March 6, 2013 04:22

you mean it solved by pressure based method? or density based?


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