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Troubleshoot sudden divergence of a transient DDPM model

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Old   April 15, 2019, 14:07
Default Troubleshoot sudden divergence of a transient DDPM model
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Pramod Narayan
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I am currently working on a transient DDPM model which blows up due to divergence detected in AMG solver K. I also see a message on the console window saying "Negative omega in x cells after linear solve". I have never seen this type of message in Fluent before.

This simulation basically shows the flow of material through a transfer chute into a riser duct. The simulation converges at each time step within 30-40 iterations until it does on a diverging loop and eventually blows. The continuity residuals at the start of the diverging loop shoots up. The monitored quantities all look reasonable till the simulation diverges. There are no indications that the simulations will diverge

In such a case, how should one troubleshoot the cause for the divergence? The mesh quality is okay with the minimum orthogonal quality at 0.15 and maximum skewness at 0.85.

I would really appreciate if somebody can help me with comments and suggestions

Any help or suggestions would be very much appreciated.
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ansys fluent, ddpm, divergence amg solver, divergence of velocity

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