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Old   June 1, 2011, 09:58
Default multiphaseInterFoam: cycleAlpha
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Claus Meister
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Hello Foamers,

can anybody explain briefly the meaning of cycleAlpha in multiphaseInterFoam.

Cheers in advance
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Old   June 4, 2011, 03:10
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Masashi Ohbuchi
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Hi,
If you cycleAlpha set to 'yes' in fvSolution, reference phase (refPhase) will change in sequential order in the correction loop of "multiphaseMixture.solveAlpha" function.
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Old   June 4, 2011, 07:02
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Okay, I understand so far! But I can't see the purpose; can you explain that, please?

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Old   June 4, 2011, 16:55
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I suppose, cycleAlpha may avoid for accumulating strain to specific phase.

For the reference phase, "alpha = 1 - Sum of alpha other phases".
This constraint must be needed for mass conservation, but for reference phase not very accurate.
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Old   June 4, 2011, 16:58
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Alberto Passalacqua
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Hi,

performing subCycles consists in performing sub-stepping in time. Take a look at:

http://foam.sourceforge.net/docs/cpp..._8H_source.php
http://foam.sourceforge.net/docs/cpp..._8H_source.php

Best,
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Old   June 5, 2011, 03:41
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Strange: Under usage of that option my water phase disappears; if I don't use cycleAlpha then all the phases are there but the min/max values vary from -161 to 31.
Has anybody ever seen anything like that?

In general, are not multiphase phase flow simulation well-engineered?
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Old   June 5, 2011, 19:05
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Quote:
Originally Posted by idrama View Post
Strange: Under usage of that option my water phase disappears; if I don't use cycleAlpha then all the phases are there but the min/max values vary from -161 to 31.
Has anybody ever seen anything like that?
No I did not see this caused by alpha sub-cycles. More information is required however to answer you properly.

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Old   June 6, 2011, 03:14
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I wanna simulate a vessel with an thin oil layer at the wall surrounded by air. Initially, there is no water in the tank, rather, the water is being injected via a nozzle. When cycleAlpha is turned on the water jet vanished, and so vice versa. Using the interFoam solver with sub. water and air everything goes fine, even there is no water in the domain at t0.
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Old   June 6, 2011, 06:37
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Hi,
I've calculate tutorial case damBreak4phase without cycleAlpha option.
And I attached result of alphaair contour, with or without cycleAlpha.
I think both results are almost same.
Attached Images
File Type: jpg WithCycleAlpha.jpg (18.9 KB, 13 views)
File Type: jpg WithoutCycleAlpha.jpg (18.6 KB, 11 views)
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Old   June 6, 2011, 06:38
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Masashi Ohbuchi
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I'm sorry. These contour picture were alphawater, not alphaair.
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