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-   -   inlet outlet boundary using timeVaryingMappedFixedValue (http://www.cfd-online.com/Forums/openfoam-solving/117771-inlet-outlet-boundary-using-timevaryingmappedfixedvalue.html)

Gildeh May 15, 2013 00:42

inlet outlet boundary using timeVaryingMappedFixedValue
 
Hello All,

I need a fully developed velocity profile as an inlet boundary condition so at first I want to develop this profile in a straight pipe and use the outlet values.
I believe that I need to use timeVaryingMappedFixedValue patch in my 0/U boundary condition for velocity in the target case. And as I read the other threads, the outlet patch coordinates should be the same as the inlet in the target case (this is true in my case). According to the tutorial in the pitzDailyExptInlet, I need two dictionary that I do not know how to extract from my initial case (these are obviously the data on the outlet patch in the initial run): (i) the points dictionary in the boundaryData folder, and (ii) the U dictionary in the 0 file.

I have already checked several threads here, but could not understand how to get these data from my initial run (e.g.: Inlet reading from a different case..)

Thank you very much in for your help in advance.

Gildeh

Pj. May 15, 2013 00:59

Mapping data for every time step
 
wrong post. Delete please, sorry

zhengzh5 May 23, 2013 14:23

Quote:

Originally Posted by Gildeh (Post 427598)
Hello All,

I need a fully developed velocity profile as an inlet boundary condition so at first I want to develop this profile in a straight pipe and use the outlet values.
I believe that I need to use timeVaryingMappedFixedValue patch in my 0/U boundary condition for velocity in the target case. And as I read the other threads, the outlet patch coordinates should be the same as the inlet in the target case (this is true in my case). According to the tutorial in the pitzDailyExptInlet, I need two dictionary that I do not know how to extract from my initial case (these are obviously the data on the outlet patch in the initial run): (i) the points dictionary in the boundaryData folder, and (ii) the U dictionary in the 0 file.

I have already checked several threads here, but could not understand how to get these data from my initial run (e.g.: Inlet reading from a different case..)

Thank you very much in for your help in advance.

Gildeh

hey, you can use the sample utility in OpenFOAM to extract the velocity profile on the outlet patch of your initial run and feed that to your actual run as inlet conditions.

check out application/utilities/postProcessing/sampling/sample, you will need to copy the sampleDict to your system directory and make necessary modifications to sample the outlet patch for specific fields.

you can read about the utility little more here:
http://www.openfoam.org/docs/user/sample.php

Gildeh May 23, 2013 14:37

Quote:

Originally Posted by zhengzh5 (Post 429581)
hey, you can use the sample utility in OpenFOAM to extract the velocity profile on the outlet patch of your initial run and feed that to your actual run as inlet conditions.

check out application/utilities/postProcessing/sampling/sample, you will need to copy the sampleDict to your system directory and make necessary modifications to sample the outlet patch for specific fields.

you can read about the utility little more here:
http://www.openfoam.org/docs/user/sample.php


Hello Jace,

Thank you very much for your reply. I actually did not see the sampling utility explanation in the user guide. I will go over that and see what would be the result.

Thanks
Gildeh

zhengzh5 May 23, 2013 15:20

Quote:

Originally Posted by Gildeh (Post 429584)
Hello Jace,

Thank you very much for your reply. I actually did not see the sampling utility explanation in the user guide. I will go over that and see what would be the result.

Thanks
Gildeh

sounds good, let me know if you have any further question. I actually just played with timeVaryingMappedFixedValue BC recently, so everything is moreless fresh in my head =)

Pj. May 24, 2013 04:09

I'm trying to do exactly the same right now. What i found is that you need to use the sample utility do sample your source case (you need to set the output format to foamFile).

Then i use a little script to reorder the files from the sample output structure to the timeVaryingMappedFixedValue input one.

You will also need to add the header to all the files, but you can do it again with a simple script.

I'm comparing the solutions right now, because it seams that i have a problem with the coordinate system. I will let you know soon with what i found. In the meantime if you share your problems and your solutions here we can help each other.


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