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Strange Behavior of Disperse Phase

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Old   December 26, 2017, 01:04
Default Strange Behavior of Disperse Phase
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Chen Sihe
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Hi all, I am doing a two-phase simulation with twoPhaseEulerFoam recently. However, there is a problem that the behavior of particles at the inlet is quite strange. I have attached my plottings of the problem in the thread. In the picture, the x-axis indicates the axial position (axis parallel to initial particle velocity) in m, and the y-axis indicates the axial velocity in m/s
The thing is that, the velocity of the particles is set to be around 3.4m/s at the inlet, but it quickly drops to around 1.5m/s for some unknown reason; after that, it is brought back to around 2m/s by the air (quite possibly).
Now the problem is that I don't know why the velocity is brought down so quickly. Has anyone got any ideas?
Thanks a lot guys
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Old   December 26, 2017, 20:35
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Chen Sihe
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One interesting discovery/update is that, I have tried to modify many of the physical quantities, and found that if I change the volume fraction to a larger value, it seems that things go well and the behaviors are relatively good. How can this happen? I am quite confused.
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Old   December 27, 2017, 09:39
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Taher Chegini
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You didn't provide any details about the way you setup your case but I go out on a limb and say that it might be due to your mesh size since your get a better result with larger alpha. Did you conduct a mesh convergence study?
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