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How to apply a function as boundary condition

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Old   January 13, 2009, 04:48
Default Dear Foamers, I'm a newbie
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Chuang Gao
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Dear Foamers,
I'm a newbie here. For my question, I want to add a function with time and circumferential position as the variables for the inlet boundary condition.
The study object is a circular ring and the inlet radius is R2 while the outlet one is R3. The inlet condition should be V2=V_mean+sin(Omega*t+phi), in which the Omega is the angular velocity and a constant in this expression. V_mean and phi (initial position) are also constants, t is the time for unsteady calculation. Can such kind of boundary condition be given? For fluent, this is very easy through using the UDF.
Thanks all.
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Old   January 15, 2009, 04:49
Default i need to run a combustion pro
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VIJAYAKUMAR R
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i need to run a combustion problem.... i used XI-foam as solver, while running some errors are coming... i need to know which solver is good for combustion problem.. and few guidelines for solving combustion problem.
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Old   January 15, 2009, 06:07
Default OK. Let's see: http://openfoam
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Bernhard Gschaider
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OK. Let's see: http://openfoamwiki.net/index.php/Ho..._Message_Board

You hit the points 1,2,3,5 and 7. Not a bad score. But it means it is very unlikely that you'll get an answer. No offense.
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Old   January 15, 2009, 06:53
Default Ok, I'd like to use the DNS so
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Ok, I'd like to use the DNS solver in OpenFoam 1.5.
Is this information clear?
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Old   January 15, 2009, 07:14
Default Hi Chuang I am certain that
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Niels Gjoel Jacobsen
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Hi Chuang

I am certain that Bernhard's comment was not minded on you, but on the person who hijacked the thread.

As a answer to your question, I cannot see any spatial variation in your boundary condition, thus you might be able to achieve what you are after by applying "timeVarying<something>". I am not at a OF-machine at the present, but you should be able to find it using the search function.

Best regards

Niels
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Old   January 15, 2009, 15:47
Default Hi Chunag! Niels is right.
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Hi Chunag!

Niels is right. I meant the other poster. Sorry if I upset you

Bernhard
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Old   January 15, 2009, 22:26
Default Hi, Niels and Bernhard, If
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Chuang Gao
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Hi, Niels and Bernhard,
If you plot the function I posted, it has nonuniform distribution along the circumferential direction. for a function, such as sin(n*theta) is a kind of flower function. theta is the circumferential coordinate. I've noticed a poster which talked about parabolic inlet boundary condition. But there do existed some differences. Can anybody give me a hint?
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Old   January 18, 2009, 16:03
Default Hi Chuang There is not prob
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Niels Gjoel Jacobsen
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Hi Chuang

There is not problem in specifying boundary conditions, which are varying both in space and time.

I you want to give a Dirichlet condition, then I would recommend you to find parabolicInlet-BC, which you will be able to find on this forum. This you should be able to modify to the purpose you are considering.

When you have implemented your own conditions just compile the BC using the wmake-procedure, link the BC to the solver of your choice, and you should be well off.

Good luck,

Niels
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Old   January 19, 2009, 19:45
Default Hi Niels, Thx for your kin
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Chuang Gao
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Hi Niels,
Thx for your kind help! I'll try it and post my results here.

Best Regards,
Chuang Gao
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Old   February 12, 2009, 11:22
Default Hi everybody, I'm dealing wit
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Andrea Petronio
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Hi everybody,
I'm dealing with boundary condition as function of a calculated scalar fields. I think to derive it from a fixedValue bc. Someone have already done something similar?
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