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-   -   Displying interface of liquid water using VoF model (http://www.cfd-online.com/Forums/fluent/114458-displying-interface-liquid-water-using-vof-model.html)

pchoopanya March 11, 2013 12:46

Displying interface of liquid water using VoF model
 
2 Attachment(s)
Hello there,

I am using a VoF model in FLUENT to model the effect of a gas and wall channel hydrophilicity on the water removal ability.

Basically, I have a simple U-turn flow channel, the air goes in at the inlet and exits at the outlet. At the bottom of the channel, a flux of liquid water is applied.

After the simulation is converged, some of the liquid water form a liquid film covering the bottom surface of the flow channel. In some cases, there is no liquid film, but some of the liquid accumulates at the corners.

Please refer to the pictures attached.

Attachment 19779

Attachment 19780

My question is simple, for a transient simulation, can we not show the animation of a liquid water? a droplet? Is it the same as defining an ISO-surface of volume fraction of liquid water and then record it at each time step when the simulation progresses?

Regarding the ISO-surface of the volume fraction of liquid water, what should be the value of interest? Which value represent the water droplet interface? Is it 0.1? or 1? I have seen somebody mention a 0.5 would be what I want, can someone confirm this please?



Best regards,

Pattarapong

oj.bulmer March 11, 2013 14:29

Yes, you need to save the VF of water at every step to be able to have any animation.

Regarding free surface, how about this... Plot a graph of VF versus height from bottom of the channel to top. You will see the VF of water going from 1 to 0 (Or values close to 0) over a transition distance. This is your layer of free surface, transitioning from water to air. Focus on this transition layer and spot the VF of water exactly in the middle.

Use this VF to generate isosurface.

Workable, unless someone has better idea :)

OJ

pchoopanya March 15, 2013 17:42

Thank you very much for your valuable comment, i'll try this !


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