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time varying velocity boundary condition

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Old   August 23, 2017, 03:49
Default time varying velocity boundary condition
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Przemek
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Hi All,
I want to write a BC where in each iteration gradient of U is calculated and applied on the wall. From which type of BC should I start?
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Old   August 25, 2017, 05:55
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Hy Przemek,

can't you just use "timeVaringMappedFixedValue"-BC? See for example the pitzDailyExptInlet-tutorial.

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Old   August 28, 2017, 13:04
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Hi Hannes,
Thank you very much for your respond.

timeVaringMappedFixedValue BC seems to be to complicated for me.
I am wondering if I can start from fixedValue BC which is basic one.
In my casy in each iteration I only need to calculate gradient of velocity and apply it on a wall. Do you think that this BC is appropriate?
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Old   August 29, 2017, 03:50
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Hi Przemek,

maybe I don't quite get your intention. How do you want to calculate the gradient? Are you doing that with some other parameters? Then I would try to take one of the BCs from the src/finiteVolume/fields/fvPatchFields/derived/ folder and delete what you don't need (e.g. fixedShearStress). For me it is easier to adapt them instead of the higher level BCs.

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Old   August 29, 2017, 12:48
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Hi Hannes,
Basically, I have Ubis variable which is a function of some parameters. Ubis is a volVectorField and I calculate it in each iteration. I have to assign to the wall Ubis component which is parallel to the wall. So I have to assign a nonuniform field on the walls and I do not know which type of BC is good for a starting point.
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