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Steady state in VOF

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Old   December 14, 2002, 22:50
Default Steady state in VOF
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I have been running VOF simulations in fluent 6. The problem is prety simple, a drop of liquid falling over a sphere at very small velocities. Air is flowing around at velocities 50% higher. Some simulations have reached 12 real seconds but the streamline function lines keep on changing.

May I expect to reach to steady state?

Thnx for any idea.

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Old   December 15, 2002, 00:20
Default Re: Steady state in VOF
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MissNancy
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Have you started with unsteady state conditions? The liquid drop is falling from the top on a sphere (EXACTLY from the top?)? Are you modeling the liquid film on a sphere by VOF? From which direction the air is flowing?

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Old   December 16, 2002, 01:27
Default Re: Steady state in VOF
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I have started with a seemingly realistic shape ( but still unsteady) of the fluid, expecting the shape of the film as part of the solution.

The liquid drop falls exactly from the top.

Yes, I'm modeling the liquid film on the sphere by VOF and the air is flowing concurrently downward.

Thanks for your answer.

Yours truly

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Old   December 16, 2002, 01:41
Default Re: Steady state in VOF
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Whats the film thickness you are expecting? Whats the weber/capillary number?

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Old   December 18, 2002, 17:11
Default Re: Steady state in VOF
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The Weber number I'm using are of the order of 10-3 to 10-4, calculated by We=viscosity*velocity/surface tension

I don't know how to estimate the film thickness, can you please provide me some information?

thnx

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