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How to have spatially varying inlet velocity profile for a multiphase flow

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Old   September 28, 2017, 08:27
Default How to have spatially varying inlet velocity profile for a multiphase flow
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rjan Kvamme
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Hi folks,

Looking for input on how to set a spatially varying inlet velocity for example linear:

U(y) = S*y

The flow is multiphase (air, water), where the water part is the one that needs to have the spatially varying velocity.

Preferably there is also a way to change the initial velocity in the water part as well, maybe by using the setFields utility and topoSet?
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Old   October 4, 2017, 14:44
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Thomas Evans
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The setFields utility can set cell values and/or face values. What you need here is face values on the inflow patch. This fragment from setFieldsDict should give you the idea.

defaultFieldValues
(
volVectorFieldValue U (0.4 0 0)
);


regions
(
boxToFace
{
box (-1 -1 -30) (1 1201 -27.5);

fieldValues
(
volVectorFieldValue U (0.267863 0 0)
);
}
boxToFace
{
box (-1 -1 -27.5) (1 1201 -25);

fieldValues
(
volVectorFieldValue U (0.313519 0 0)
);
}
boxToFace
{
box (-1 -1 -25) (1 1201 -22.5);

fieldValues
(
volVectorFieldValue U (0.334759 0 0)
);
}
// ... more boxes
)

Oops, I missed the part where you said ICs as well. Same idea, but use boxToCell with boxes that cover the required volumes. If making the variation smooth is crucial, you probably want to use funkySetFields.
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Old   October 5, 2017, 05:42
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rjan Kvamme
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Smooth variation is ideal, so I should try funkySetFields. Do you need to compile something to get funkySetFields to get it. It just says command not found when I try to execute.

I am currently running OpenFoam 5.0.
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Old   October 5, 2017, 09:16
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Thomas Evans
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funkySetFields is part of swak4foam -- https://openfoamwiki.net/index.php/Contrib/swak4Foam
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