interFoam: strange doplet behaviour at mesh transition

geth03 · December 8, 2023, 07:29

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.

geth03 · December 15, 2023, 03:57

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.

anubasu · December 17, 2023, 03:16

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?

geth03 · December 17, 2023, 11:16

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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December 17, 2023, 03:16		#3
anubasu Member Anurag Join Date: Feb 2023 Posts: 66 Rep Power: 3	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?

December 17, 2023, 11:16		#4
geth03 Senior Member Join Date: Dec 2019 Location: Cologne, Germany Posts: 363 Rep Power: 8	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.