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Using interFoam, phase piles up at pipe outlet

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Old   August 22, 2010, 15:34
Default Using interFoam, phase piles up at pipe outlet
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Dear foamers,

I have put up a relatively simple case using interFoam, based on the approach in damBreak and 2D nozzle tutorials. I use setFields to "place" a load of water inside a pipe, which then is supposed to flush through the S-shaped geometry, and out. However, the water does not seem to exit the pipe at all. I have the following BCs (using OF 1.7.x):

alpha0:

inlet
{
type inletOutlet;
inletValue uniform 0;
value uniform 0;
}
outlet
{
type inletOutlet;
inletValue uniform 0;
value uniform 0;
}

U:

inlet
{
type zeroGradient;
}

outlet {
type zeroGradient;
}

p_rgh:
inlet
{
type fixedValue;
value uniform 0;
}

outlet
{

type fixedValue;
value uniform -200;
}
Attached Images
File Type: jpg alpha_0.jpg (19.4 KB, 30 views)
File Type: jpg alpha_0.78.jpg (43.7 KB, 29 views)
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Old   August 23, 2010, 03:44
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Sebastian Gatzka
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You force alpha0 to be zero all the time at the inlet an outlet.
I think a zeroGradient would be more appropriate - at least for the outlet.
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Old   August 23, 2010, 06:35
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Are you sure about this? My perception of the inletOutlet "value", is that this is the initial value, and changes as the simulation proceeds. Though if this was a fixedValue type, I would agree...
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Old   August 23, 2010, 08:39
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The inletOutlet

Quote:
switches and between fixedValue and zeroGradient depending on direction of
(http://www.openfoam.com/docs/user/bo...hp#x24-1390293)

The value-entry will then correspond to the case of fixedValue.
But I'm not sure how this "switch" will work.
But there is some fixedValue involved in this may be the problem.

I think inletOutlet is better for velocity or pressure, not for alpha0.
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Old   August 24, 2010, 03:18
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I do see your point. The tutorials for interFoam, however, all use inletOutlet for alpha0.
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