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Falling Droplet using InterFoam

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Old   October 16, 2013, 12:28
Default Falling Droplet using InterFoam
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Kostis
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Hi guys,

I am trying to simulate a 3D droplet falling due to gravity forces with interFoam as simple as that. When the droplet reaches a velocity I will put it in a jet flow using mapFields. I have encountered some strange things and I cant even do the first part.

a) Should I change the pressure inside the droplet due to the surface tension? p=2*sigma/r. What about the distribution of pressure inside the droplet due to gravity?

b) Do you believe that the outcome would be the same if I enter a velocity in funkySetFieldsDict?

c) Finally, the droplet disintergrates very quickly before it reaches the velocity (1m/s) which is totally unnatural. Why is that? (personally, I do not think it is about contact angle)

Thank you for you time

Kostis
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Old   November 12, 2013, 19:22
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Shawn Fotovati
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You should not change the pressure. Solver must calculate it during the solution.
If droplet disintegrates, I believe it is due to mesh, change the mesh and see if it is improved.

I have another problem; Right before droplet hits the surface, it stops moving, and hangs around in the air! I have no idea why this happens for my case!
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Old   December 2, 2013, 18:30
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cosbergel, I have been having trouble with a 3D droplet behaving almost the same way you described. My grid is refined to .1mm spacing for a 2mm droplet which I thought was sufficient. An order of magnitude refinement did not help. Were you able to figure out your problem? I was using multiphaseInterFoam, but the advice should probably be similar for both.

I appreciate any help!
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Old   December 3, 2013, 06:15
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Kostis
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@ sfotovati as far as the pressure is concerned, you are right that the solver calculates the pressure inside the droplet but I found out that it is better to put it as an initial condition because otherwise you ll have perturbations on the surface of the droplet.
I think that you have put wrong boundary condition on the wall.

@btsusi I manage to solve my problem firstly by not using dynamic refinement and then by changing the div schemes (specially for alpha1) for interFoam and interDyMFoam which I had it finally working. In my opinion satisfactory number of cells inside a droplet is 50- 100.

Regards,
Kostis
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Old   December 3, 2013, 10:10
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cosbergel,
Thank you for the quick response, I will try your advice!
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