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interFoam: strange doplet behaviour at mesh transition

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Old   December 8, 2023, 07:29
Default interFoam: strange doplet behaviour at mesh transition
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i am trying to simulate droplets moving on a 2D-plane,
bc of geometry my cells transition at certain points, see pic1.

right at the transition point, the lighter droplets are dragged down. compare pic 2 und 3, before and after photos.


i draw a circle around one droplet to compare the two states. that happens to all droplets but smaller droplets are carried more aggressively.

any help is appreciated.
Attached Images
File Type: jpg mesh.jpg (67.0 KB, 15 views)
File Type: jpg pic2.jpg (11.5 KB, 20 views)
File Type: jpg pic3.jpg (5.5 KB, 16 views)
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Old   December 15, 2023, 03:57
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i tried various things already without success:

1. mesh refinement: i used the same meshing style but with much finer cells

2. changed meshing strategy completely with tet-mesh and unstructured hex mesh: there are droplets now that stay in place and don't move, they just wiggle around like the one in the 2 screenshots.
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File Type: jpg t2.jpg (11.0 KB, 4 views)
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Old   December 17, 2023, 03:16
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i think due to momentum of the carrier fluid smaller droplets are affected more because they are lighter. Are the droplets moving inside a liquid?
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Old   December 17, 2023, 11:16
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i played around with the numerics and solved it.

of course the carrier fluid has an impact, but the mesh transition and standard numerics lead to that unphysical flow behaviour.
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