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Satisfactory solution

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Old   June 12, 2019, 04:08
Default Satisfactory solution
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Arijit Saha
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I am performing a steady state analysis with pressure based solver and I am at a stage where I cant decide whether my solution is correct or not. This is because my residuals i.e continuity, x, y-velocity, k and epsilon have converged at 10^-5 but in my lift coef monitor the Cl is increasing at 0.0001 rate every 10th iteration. So, what should I assume now?

If anyone replies it will be of great help.
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Old   June 14, 2019, 19:56
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Hello,

The best way to determine whether your simulation is going the right way is to compare the quantities of interest (in this case Cl) to experimental data. I assume that you probably do not have any data to compare to.

Since you are interested in Cl I assume that you are modelling some kind of 3D wing or 2D airfoil section. If Cl is still increasing then you should wait until it comletelly stabilizes. If this increase, is then followed by a decrease i.e. Cl is showing an oscillating behavior, then this could be an indication that the solution might be transient or mesh resolution is not appropriate.

In any case, I believe that the rate of change of 0.0001 is not significant in the case of Lift coefficient so you are safe to regard this as a converged solution. Just in case, let it run a bit more iterations to see whether it stops rising after all.

Best,
Ioannis
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