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VOF- 0.7s in 13 days

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Old   December 25, 2004, 14:36
Default VOF- 0.7s in 13 days
  #1
anni
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I am running a 2D two phase problem, air-oil. I have a disk rotating (3000 rpm) in a closed box. 1/3 of the box is oil. I am using VOF and k-epsilon turbulence model, it has past 13 days and i have reached 0,7 sec. My time step size is almost 1e-06 sec, all the time, to succeed convergance in every itteration. I can`t understand why it needs so little time step... there must be a problem...or not?
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Old   December 26, 2004, 12:03
Default Re: VOF- 0.7s in 13 days
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emre
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Hi,

VOF is computationally very expensive, youre right. But do not start with 1e-6 secs, but bigger time steps like 1e-3, then drop it gradually if you see non-converging residuals. Fluent v6.2 is going to have Non Iterative Time Advancing solver (NITA) which is claimed to decrease the computation times drastically.

You can download the beta version 6.2.9 from the Fluent USC.

Regards,

Emre
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Old   December 26, 2004, 18:44
Default Re: VOF- 0.7s in 13 days
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anni
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I will try it, and let you know.

Thank you my friend.

Best regards

Happy New Year,

Anni
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Old   December 26, 2004, 19:18
Default Re: VOF- 0.7s in 13 days
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zxaar
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emre , can u give the exact link for 6.2.9 ..i couldn't find it on fluent users . com
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Old   December 27, 2004, 04:44
Default Re: VOF- 0.7s in 13 days
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emre
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Hi,

It may not be appropriate for me to give the link on a public site although it requires password. All beta versions are put on the USC but no link is provided, you have to type the correct address and then you fill in a form before downloading the software. Please ask for that address from your local Fluent office or distributor.

Regards,

Emre
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Old   December 27, 2004, 05:10
Default Re: VOF- 0.7s in 13 days
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zxaar
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yes that would be correct way, i will ask fluent people.
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