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Old   January 14, 2010, 04:51
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I am trying to simulate droplets breakup in stratified air water flow: that means i ll have:
-continuous air
-continuous water
-water droplets

which definition is the most convenient for this simulation
thxx
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Old   January 14, 2010, 13:16
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Air and Water would be Eulerian phases (like a free surface simulation) and water droplets would use Lagrangian particle tracking, with a break-up model as necessary. I've never tried to set this up, so there could be limitations in CFX.
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Old   January 14, 2010, 14:21
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unfortunately it doesn't work...

are ther any breakup or separation model based on the KH-theory
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Old   July 6, 2010, 04:37
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I modeled the problem with two continuous phases and one disperse.. but when my droplets become bigger the flow pattern changed and did not suit the normal flow pattern? what shall i do
thx Jessica

Last edited by Zaktatir; July 7, 2010 at 04:04. Reason: :
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Old   July 7, 2010, 07:39
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okay i think there is no interest or idea.. that s why i change my question...
is it possible to activate a phase while calculating (phase not active till something happen)
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Old   July 7, 2010, 08:03
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Yes, definitely. You can make a source for the volume/mass fraction which is dependent on some condition being met, maybe an elapsed time. It can trigger the source term to start generating the mass/volume fraction.
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Old   July 7, 2010, 08:21
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yeah i made this but i get another flow patter as expected.
I should define a positive source: that means that droplets are being separated leading a negative source for the water phase


jessica
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Old   July 7, 2010, 19:03
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Quote:
yeah i made this but i get another flow patter as expected.
What is a "flow patter"?
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Old   July 8, 2010, 02:50
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sorry flow pattern..

I made a condition: if relative velocity betwwen water/air phase exceeds a critical velocity there will be water stripping and droplet formation. At this point the droplet phase should be activated (in each cell)... I introduced source term (for the droplet phase) and the same source term but negativ for the water phase (is this correct).. The Diameter will be then calculated (capillary waves approach)

The flow pattern should be similar to that without this additionally phase but it does not work??
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