SimScale CAE Forum

Convergence checking

Hi please can i say that the result is convergent?

renaissance | SimScale Workbench

please can someone help me ???

Hey there!

This plot, which is the convergence of the residuals, shows the maximum residual over the whole domain. If it is low enough, say all curves below 0.001, then we can say that the computation is most likely converged. But sometimes, there might be regions, often close to the boundaries, where the residuals are high while in other regions the residuals are low. This can mess with the plot you show.

To really tell if the computation is converged, you should be rather looking at the Force plot. As this is your variable of interest, you want this to be converged, and the residuals are mostly secondary.

thanks sir but this is not converge right?

I would say that it is mostly converged. You can tell for example by zooming in to the last 100 iterations, and checking the ratio of the amplitude of the variations to the mean value. If it is small, say 5%, then you can tell it is converged.

If you want to improve such ratio, then you have to perform a mesh independence analysis, e.g. refine the mesh around the area of interest.

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ok thank you sir

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Yeah, @ggiraldof is right. I will only add that the result is as converged as your grid allows for. You are using a very coarse grid. I suggest you learn to use hex-dominant parametric and do gradual refinements. Those, especially in the trailing edge, are crucial for the accuracy of the calculations. Refine where flow separation or large gradients are expected.

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ok, thank you sir