interFoam: strange doplet behaviour at mesh transition

geth03 · December 8, 2023, 08:29

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, 04:57

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, 04:16

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, 12:16

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.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
flow over cylinder in openFoam	saeed jamshidi	OpenFOAM Pre-Processing	3	August 11, 2023 16:16
Different behaviour of interFoam across versions	mrishi	OpenFOAM Running, Solving & CFD	1	June 10, 2022 19:32
decomposePar problem: Cell 0contains face labels out of range	vaina74	OpenFOAM Pre-Processing	37	July 20, 2020 06:38
Mesh motion with Translation & Rotation	Doginal	CFX	2	January 12, 2014 07:21
strange pressure behaviour with symmetricPlane boudary condition - interFoam	duongquaphim	OpenFOAM Running, Solving & CFD	10	August 20, 2013 15:00

December 17, 2023, 04:16		#3
anubasu Member Anurag Join Date: Feb 2023 Posts: 69 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, 12:16		#4
geth03 Senior Member Join Date: Dec 2019 Location: Cologne, Germany Posts: 367 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.