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August 1, 2014, 06:03 
turbulent kinetic energy budget terms with openfoam

#1 
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Thangam Natarajan
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Hi,
Is there a way to write out all the components(production, convection, dissipation and turbulent diffusion) of the tke budget separately for a LES case? Any pointers?? Thanks. Thangam. 

August 13, 2014, 15:06 

#2 
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Bruno Santos
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Greetings Thangam,
Can you provide more information about each variable you are looking to export? I ask this because even though I'm familiar with many of OpenFOAM's way of working with things, on the other hand I'm not familiar with the terminology in LES. Therefore I need more details on what exactly you're looking for. Best regards, Bruno PS: Reposting does not make it easier for people to answer your questions. What's more important is that more details are provided with each new post you provide, because if people did not answer your question, it's likely that not enough information was provided in the first place. And many of the people that might be able to answer your question, don't have the time to still have to ask first: What on Earth are you talking about?
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Last edited by wyldckat; August 13, 2014 at 15:10. Reason: see "PS:" 

August 14, 2014, 00:55 

#3 
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Thangam Natarajan
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My bad I thought these were quite obvious! Anyway,
The complete form of the turbulent kinetic energy can be written as, , where, is the production term of given by, is the mean convection term of given by, is the dissipation term of given by, and is the diffusion transport term of given by, and contains the viscous diffusion, pressure diffusion, and the turbulent diffusion given by, The problem is I am not able to identify where these terms are embedded in the code and how to write them out by creating a small utility. Thanks. 

August 14, 2014, 04:56 

#4  
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Armin
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Quote:
Code:
src/turbulenceModels/compressible/LES/oneEqEddy/oneEqEddy.H src/turbulenceModels/compressible/LES/oneEqEddy/oneEqEddy.C Last edited by dkxls; August 14, 2014 at 05:01. Reason: typo 

August 17, 2014, 14:00 

#5 
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Bruno Santos
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Greetings to all!
To complement Armin's answer: the class "oneEqEddy" is derived from the class "GenEddyVisc", which in turn derives from "LESModel". This last class is the base class for accessing turbulence data that is readily available on the solver's side. For example, have a look at the solver "applications/solvers/heatTransfer/thermoFoam" in OpenFOAM 2.3, namely in the file "setAlphaEff.H". There you can see how it explicitly loads the turbulence of type "LESModel". Correlating the information given in #3 with the information here on the wiki, it looks like the terms you've looking for are these: http://www.cfdonline.com/Wiki/Kinet...idscale_model Checking Armin's answer in post #4 does reveal the same equations in this method: Code:
void oneEqEddy::correct(const tmp<volTensorField>& tgradU) Which means that you will have to either create a new derived class from "oneEqEddy" or modify directly OpenFOAM's class "oneEqEddy", to write out each term of the equation. Or you can modify the solver and do a dynamically cast to the instance of "LESModel" class to "oneEqEddy" and then access directly the "k()" method and other methods that give the components used in the equation that is solved in "oneEqEddy::correct". Although I don't know how practical that is, because each term of the equation is in the form of "fvScalarMatrix" and not of in the form of a standard field. Best regards, Bruno
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September 5, 2015, 17:58 

#6  
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Syavash
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Quote:
I could effectively use Tecplot "Calculate Variable" option to construct each term of the production and dissipation. I think paraFoam can perform such calculations as well. Regards, Syavash 

Tags 
openfoam, tke, turbulent kinetic energy 
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