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Anna Tian July 28, 2012 17:52

Need help on my CFD homework. RMS fluctuates.
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Hello everyone,

I simulated a case by CFX-solver. But the RMS value does not converge. The mesh quality is above 0.5 at ICEM. I set the timestep very small to 0.001s. (Initially it was larger, but there's still RMS fluctuation for nearly every timestep.) I copied the boundary condition setting from my classmate. It's not likely to have any problem at it. Since I'm not allowed to distribute our homework, I can only upload my CFX-solver pictures. Hope you can give me some hints about where the problem might be. :confused:

ghorrocks July 29, 2012 07:24

This question is a FAQ:

As the residuals do not oscillate it is unlikely to be transient flow. Much more likely mesh quality (ie remesh with better quality mesh) or numerical precision (ie try double precision).

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