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Artificial high pressure under an impacting droplet using interFoam

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Old   November 29, 2014, 10:24
Default Artificial high pressure under an impacting droplet using interFoam
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hadisafaei
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Hi all.
I'm trying to simulate the impingement of a Glycerin drop to a solid surface using interFoam solver and laminar model(OpenFoam 2.3) .When a droplet approached another surface, air in the gap between them was forced out and it's pressure increased .numerical simulation shows that air pressure increases sharply (up to 100000pa) under the droplet and causes some air trap in the drop . Due to the low speed of droplet(5.94 m/s) this increased pressure seems not be true.

Can someone give me a hint on how can I get better results?
What could be the reasons?
settings are attached below
Thanks for any help.
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File Type: zip setup.zip (10.6 KB, 8 views)
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Old   November 30, 2014, 14:54
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Hi Hadi,
Welcome to the forum.

Well, I ran your case.
Actually since we are dealing with incompressible fluids (interFoam) then pressure difference is the parameter we are searching for.

In your case this value is 100 pa between droplet center and adjacent surrounding air.

Isn't it correct !? Any paper to validate or verify with !?

Best.
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Old   November 30, 2014, 16:11
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Hi Mojtaba
Thanks for your quick reply.
ّI think It is necessary to further explain.
I mean , the air pressure under droplet when droplet closed to solid surface , not difference between droplet pressure and surrounding air.

Yes there are some papers for validation, for example " Air bubble entrapment under an impacting droplet " written by V. Mehdi-Nejad, J. Mostaghimi, and S. Chandra ; phys. Fluids

*But there is significant difference between my results and their results.To clear the subject two pictures are attached below.
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File Type: jpg alpha.jpg (29.5 KB, 21 views)
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Old   November 30, 2014, 16:39
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In time 0.6 I get something like this,


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Old   November 30, 2014, 17:06
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Thanks
But i want air pressure before droplet impact to the surface
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