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how to calculate rms velocity fluctuation after runtime

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Old   August 11, 2012, 09:44
Default how to calculate rms velocity fluctuation after runtime
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Hello ,

I used les model but I cant calculate rms velocity fluctuations or reynolds stress tensor . Does anyone know how we can calculate rms velocity fluctuations during post-processing?

Thanks so much,
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Old   August 14, 2012, 17:32
Default uprime calculation
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Ali Lohrasbi Nichkoohi
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hi nati
after your solution is terminated, just write in terminal window( your runs directory): uprime
the velocity fluctuation is calculated and save on your folder runs.
see page 93 of openfoam userguide.
nichkoohi@yahoo.com
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Old   August 14, 2012, 20:28
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Quote:
Originally Posted by nichkoohi View Post
hi nati
after your solution is terminated, just write in terminal window( your runs directory): uprime
the velocity fluctuation is calculated and save on your folder runs.
see page 93 of openfoam userguide.
nichkoohi@yahoo.com

hi,

tnx! In uprime, it has been hypothesized that rms velocity fluctuations in diffrent directions are same and equal with sqrt (2/3k)!
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Old   November 9, 2012, 02:40
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Hi,

I also dealt with that problem. I wrote a small tool called

postAverageTurbulenceFields

which iterates over all the timesteps in your directory and writes out the whole set of turbulence properties

k, eps, nu_eff, R, R_eff, Umean, UPrime2Mean

So far it works for LES turb models but modification to RAS turb models should be easy. You still need that tool?

it's basically an extension of the tool postAverageFields by eelcovv
using fieldAverage library to average postprocessing
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Old   December 9, 2012, 10:13
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Dear Hanzo,
Pardon me for being late in answering you.
Yes , I still need it so much.
can you help me on this issue ?
Regards,
Nati



Quote:
Originally Posted by Hanzo View Post
Hi,

I also dealt with that problem. I wrote a small tool called

postAverageTurbulenceFields

which iterates over all the timesteps in your directory and writes out the whole set of turbulence properties

k, eps, nu_eff, R, R_eff, Umean, UPrime2Mean

So far it works for LES turb models but modification to RAS turb models should be easy. You still need that tool?

it's basically an extension of the tool postAverageFields by eelcovv
using fieldAverage library to average postprocessing
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Old   February 5, 2013, 06:50
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Hi Hanzo, I am interested in your tool, too. I work with the hybrid LES / RANS models of the LEMOS extensions and I have to think well about how to visualize the turbulent fluctuations due to LES and RANS seperateley. I would be happy if I could have a look at your code...
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Old   February 7, 2013, 09:42
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Quote:
Originally Posted by nati View Post
Dear Hanzo,
Pardon me for being late in answering you.
Yes , I still need it so much.
can you help me on this issue ?
Regards,
Nati
Quote:
Originally Posted by vonboett View Post
Hi Hanzo, I am interested in your tool, too. I work with the hybrid LES / RANS models of the LEMOS extensions and I have to think well about how to visualize the turbulent fluctuations due to LES and RANS seperateley. I would be happy if I could have a look at your code...
Sorry for the late answer. Please find my code here:

Utilities: post average turbulence fields and create turbulence fields for LES

Let me know if it works

Best,
Hanzo
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