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July 30, 2013, 10:51 |
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#1 |
Senior Member
Bobby
Join Date: Oct 2012
Location: Michigan
Posts: 454
Rep Power: 15 |
Dear guys
Hi I want to write the sub-grid scale mixture fraction variance expression in Open FOAM. In this expression, we have delta that means filter size. Would somebody PLZ hint me that How do we write filter size in Open FOAM? (merged from another post) I want to write the expression in LES for mixture fraction variance. In this expression we have filter size (delta). would somebody hint me how can I write filter size in OpenFOAM format? Regards Bobi Last edited by wyldckat; August 18, 2013 at 18:07. Reason: the two posts were made in two separate threads and the topic is nearly identical |
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August 18, 2013, 18:08 |
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#2 |
Retired Super Moderator
Bruno Santos
Join Date: Mar 2009
Location: Lisbon, Portugal
Posts: 10,975
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Greetings Bobi,
Please provide more details on what exactly you want to do. Best regards, Bruno
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August 19, 2013, 01:57 |
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#3 |
Senior Member
Bobby
Join Date: Oct 2012
Location: Michigan
Posts: 454
Rep Power: 15 |
Hi Bruno
As you might Know, libOpenSmoke and its modified versions does not support LES solver, I am trying to write a solver that involves LES solution and 80% I was successful. There was a failure in my thermochemical data (not velocity or mixture fraction fields). I have found that it is because I have used a transport equation for mixture fraction variance. Instead I should have exerted a modeling formulation. Fortunately fireFoam (which has a kind of flamelet solver: FSD) has implemented this modelling formulation in a way. I am trying to implement it into modified OpenSmoke to finally create the LES solver . This is what I found in FSD.H file: Code:
// Calculation of the mixture fraction variance (ftVar) const compressible::LESModel& lesModel = YO2.db().lookupObject<compressible::LESModel>("LESProperties"); const volScalarField& delta = lesModel.delta(); const volScalarField ftVar(Cv_*sqr(delta)*sqr(mgft)); Regards Bobi |
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August 21, 2013, 11:12 |
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#4 |
Retired Super Moderator
Bruno Santos
Join Date: Mar 2009
Location: Lisbon, Portugal
Posts: 10,975
Blog Entries: 45
Rep Power: 128 |
Hi Bobi,
My guess is that this delta size is actually defined in the dictionary "constant/LESProperties". You can find several examples on OpenFOAM, by running: Code:
find $FOAM_TUTORIALS -name "LESProperties" By the way, the OpenFOAM User Guide is a bit vague on how these are used:
Best regards, Bruno
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August 21, 2013, 11:26 |
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#5 |
Senior Member
Bobby
Join Date: Oct 2012
Location: Michigan
Posts: 454
Rep Power: 15 |
Hi Bruno
I am going to take a deep look at your hints. Many thanks for your kind reply. Regards Bobi |
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November 22, 2022, 14:26 |
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#6 |
New Member
Sandeep
Join Date: Apr 2017
Location: IIT Delhi, New Delhi, India
Posts: 13
Rep Power: 9 |
Hi all.
Greeting! I am also trying to access LESDelta. Actually in the transport equation of variance of mixture fraction (varZ) it is required for calculating scalar dissipation of mixture fraction. When I type delta or LESDelta an error appear saying : "delta/LESDelta is not declared in this scope". Can anyone please suggest how to access it. Thanks and regards Sandeep Lamba |
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December 1, 2022, 21:07 |
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#7 |
New Member
Join Date: Aug 2017
Posts: 16
Rep Power: 8 |
Hi Sandeep,
I am also trying to access LESDelta to solve scalar dissipation rate. Did you solve this problem? Regards, Shang |
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December 31, 2022, 09:21 |
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#8 |
New Member
Sandeep
Join Date: Apr 2017
Location: IIT Delhi, New Delhi, India
Posts: 13
Rep Power: 9 |
Hi Wang Shang,
I could not actually access the LESDelta directly but I solve the problem by locally calculating Delta from local cell volume by accessing mesh properties. regards |
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