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-   -   How to set up the velocity in the let boudary changing with time. (https://www.cfd-online.com/Forums/openfoam-solving/65088-how-set-up-velocity-let-boudary-changing-time.html)

 flying June 3, 2009 10:23

How to set up the velocity in the let boudary changing with time.

Hey Foamers:

I wish all of you have a nice day.
I need to simulate a case that the velocity in the inlet changes with the time.
How do I set up it ?
Is there existed solver or text that could be referenced by me?

Thanks and best wishes!

 leonardo.morita June 3, 2009 10:57

Hi,

I've not used it yet, but it seems that timeVaryingMappedFixedValue can be useful for you.

Regards,

Leonardo

 ngj June 3, 2009 11:11

And if the time variation can be specified by a mathematical expression you would benefit from groovyBC (just search the forum).

Best regards,

Niels

 flying June 3, 2009 11:25

Thanks a lot to eonardo and Niels. I will try it.

 flying June 4, 2009 12:08

Hey Leonardo:

How do I use it? And how could I generate the value for different time step?

Thanks and Best wishes!

 leonardo.morita June 4, 2009 15:59

Hello,

Well, I know it's not extensively documented, but you can search for more info here in the forum. Try the keywords: transient boundary conditions, timeVarying, nonuniform boundary conditions etc.

"Is it a utility?"
- it's a kind of boundary condition you can use with U, p etc (like fixedValue, zeroGradient...)

"How do I use it?"
- you can take a look into the simpleFoam/pitzDailyExptInlet tutorial for syntax and more

"And how could I generate the value for different time step?"
- as I don't know anything about your case and as I've never used it, it's a bit difficult to answer this one ;)

Regards,

Leonardo

 flying June 5, 2009 08:50

Thanks for your answer. I would like to know where I could see the source code for this boundary condition. I guess from the source code, I could get more information.

Best wishes!

 leonardo.morita June 5, 2009 09:26

Here: OpenFOAM-1.5\src\finiteVolume\fields\fvPatchFields\derived

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