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Old   December 21, 2012, 12:40
Default Extremely high residuals
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Hi all,

I understand that residuals are often meaningless, but I am running a multiphase hydraulic jump model in an open channel which *seems* to be outputting the correct flow, but the residuals are extremely high. For example, Tdr is between 10,000 and 100,000, H20 is 1000, Tke is 800 etc. The only one below 1 is Continuity at 0.3.

I am quite confused as to why this is... I am new to multiphase mixtures and flows. The simulation is being run in 2D and I have around 2,000,000 cells for a model that is around 2.7 metres in length, and each timestep is 0.001 seconds with 10 iterations for each step.

Here is an image of the model at ~15 seconds:



Also, I have just been chasing the reason for the strange flow profile over the first obstacle. Apparently it is due to the clinging nappe profile. Does anyone know a good way to remediate this problem? I understand the profile is caused by a vacuum, and that ventilation in this region should stop it, but how can I do this? Using an air velocity inlet on the end of the first object?
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