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January 13, 2009, 04:48 
Dear Foamers,
I'm a newbie

#1 
New Member
Chuang Gao
Join Date: Mar 2009
Posts: 12
Rep Power: 9 
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. 

January 15, 2009, 04:49 
i need to run a combustion pro

#2 
New Member
VIJAYAKUMAR R
Join Date: Mar 2009
Location: BANGALORE, KARNATAKA, INDIA
Posts: 20
Rep Power: 9 
i need to run a combustion problem.... i used XIfoam 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.


January 15, 2009, 06:07 
OK. Let's see: http://openfoam

#3 
Assistant Moderator
Bernhard Gschaider
Join Date: Mar 2009
Posts: 3,926
Rep Power: 41 
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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January 15, 2009, 06:53 
Ok, I'd like to use the DNS so

#4 
New Member
Chuang Gao
Join Date: Mar 2009
Posts: 12
Rep Power: 9 
Ok, I'd like to use the DNS solver in OpenFoam 1.5.
Is this information clear? 

January 15, 2009, 07:14 
Hi Chuang
I am certain that

#5 
Senior Member
Niels Gjoel Jacobsen
Join Date: Mar 2009
Location: Deltares, Delft, The Netherlands
Posts: 1,698
Rep Power: 27 
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 OFmachine at the present, but you should be able to find it using the search function. Best regards Niels
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January 15, 2009, 15:47 
Hi Chunag!
Niels is right.

#6 
Assistant Moderator
Bernhard Gschaider
Join Date: Mar 2009
Posts: 3,926
Rep Power: 41 
Hi Chunag!
Niels is right. I meant the other poster. Sorry if I upset you Bernhard
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January 15, 2009, 22:26 
Hi, Niels and Bernhard,
If

#7 
New Member
Chuang Gao
Join Date: Mar 2009
Posts: 12
Rep Power: 9 
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? 

January 18, 2009, 16:03 
Hi Chuang
There is not prob

#8 
Senior Member
Niels Gjoel Jacobsen
Join Date: Mar 2009
Location: Deltares, Delft, The Netherlands
Posts: 1,698
Rep Power: 27 
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 parabolicInletBC, 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 wmakeprocedure, link the BC to the solver of your choice, and you should be well off. Good luck, Niels
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January 19, 2009, 19:45 
Hi Niels,
Thx for your kin

#9 
New Member
Chuang Gao
Join Date: Mar 2009
Posts: 12
Rep Power: 9 
Hi Niels,
Thx for your kind help! I'll try it and post my results here. Best Regards, Chuang Gao 

February 12, 2009, 11:22 
Hi everybody,
I'm dealing wit

#10 
Member
Andrea Petronio
Join Date: Mar 2009
Location: Trieste, Italy
Posts: 38
Rep Power: 9 
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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