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Help with tke and sdr convergence

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Old   May 22, 2020, 18:38
Default Help with tke and sdr convergence
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Adrian Rouco
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Hello everyone,

I am having a little problem, I have tweaked the relaxation factors following the rule of adding 1 between pressure and velocity and I was getting good results, but now in a new simulation I am getting divergent turbulence sdr and tke after 1000 iterations.

Does anyone know why is this happening? It is not a problem of geometry as it has been prepared for CFD and the mesh is as good as it can be taking into account the computational resources.

Here you can see what I mean by the residuals diverging.

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Old   May 23, 2020, 03:31
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more details needed
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Old   May 23, 2020, 22:07
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What kind of details? The physics model used is an SST k-w gamma transition, it is segregated flow where the relaxation factor of velocity goes from 0.8 to 0.2 linearly and the opposite for the pressure (i.e. from 0.2 to 0.8). [This gave me quite good stability and steady forces]. Don't know what else can I say about it, mesh is good, y+ below 1, growth factors are 1.1 or less..., geometry is healed...
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Old   May 26, 2020, 04:51
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Quote:
Originally Posted by rouco75 View Post
What kind of details? The physics model used is an SST k-w gamma transition, it is segregated flow where the relaxation factor of velocity goes from 0.8 to 0.2 linearly and the opposite for the pressure (i.e. from 0.2 to 0.8). [This gave me quite good stability and steady forces]. Don't know what else can I say about it, mesh is good, y+ below 1, growth factors are 1.1 or less..., geometry is healed...
Well, a finer mesh maybe help. From your residual plots, the convergence is not so good even in the first 600 iterations.
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