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Howto get the production and dissipation of TKE?? |
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June 27, 2009, 05:44 |
Howto get the production and dissipation of TKE??
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#1 |
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Daniel WEI (老魏)
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Anyone knows how to get the production and dissipation of TKE (turbulence kinetic energy)? Thanks
Is it in this way: Code:
volSymmTensorField D = symm(fvc::grad(U)); //volTensorField Dprim = symm(fvc::grad(U - UMean)); volScalarField prod = -((U - UMean)*(U - UMean)) && D; volScalarField epsilon = sgsModel->epsilon();
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~ Daniel WEI ------------- Boeing Research & Technology - China Beijing, China Last edited by lakeat; June 28, 2009 at 07:14. |
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July 6, 2010, 11:55 |
Production and dissipation of TKE
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#2 |
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Dear Daniel
I am also interested in this topic. Therefore, I would like to know if you found an answer to your question in the meantime. Cheers, Irina |
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July 6, 2010, 12:26 |
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#3 |
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Daniel WEI (老魏)
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Sorry, it'e been a long time, but doesn't the codes in my last post work for you?
you can try with a channel case and see if its distribution is correct. Bye
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~ Daniel WEI ------------- Boeing Research & Technology - China Beijing, China |
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December 13, 2010, 18:51 |
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#4 |
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John Deas
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Hi,
why did you take the symmetrical part of grad(U) ? Why didn't you compute Code:
R && fvc::grad(Umean) Regards, JD |
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December 14, 2010, 04:55 |
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#5 |
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Alberto Passalacqua
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Notice that the method epsilon() returns the SGS dissipation rate. Check doxygen to see how it is computed, depending on the specific model.
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Alberto Passalacqua GeekoCFD - A free distribution based on openSUSE 64 bit with CFD tools, including OpenFOAM. Available as in both physical and virtual formats (current status: http://albertopassalacqua.com/?p=1541) OpenQBMM - An open-source implementation of quadrature-based moment methods. To obtain more accurate answers, please specify the version of OpenFOAM you are using. |
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December 14, 2010, 09:18 |
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#6 |
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John Deas
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Hi Alberto,
thank you for your answer. When I take a look at src\turbulenceModels\LES\incompressible\oneEqEddy\ oneEqEddy.C, I read: Code:
void oneEqEddy::correct(const tmp<volTensorField>& gradU) { GenEddyVisc::correct(gradU); volScalarField G = 2.0*nuSgs_*magSqr(symm(gradU)); solve ( fvm::ddt(k_) + fvm::div(phi(), k_) - fvm::laplacian(DkEff(), k_) == G - fvm::Sp(ce_*sqrt(k_)/delta(), k_) ); bound(k_, k0()); nuSgs_ = ck_*sqrt(k_)*delta(); nuSgs_.correctBoundaryConditions(); } Code:
ce_*sqrt(k_)/delta() Code:
2.0*nuSgs_*magSqr(symm(gradU)) I also do not understand why the symmetric part of the gradient of U is mentionned in the previous post. Regards, JD |
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December 14, 2010, 10:34 |
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#7 |
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David Boger
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The double-inner product of a symmetric and asymmetric second-rank tensor is zero, so in that sense, only the symmetric part of gradU "survives" anyway. So using only the symmetric part is harmless, but perhaps unnecessary.
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David A. Boger |
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December 14, 2010, 12:21 |
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#8 | |
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Alberto Passalacqua
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Quote:
volScalarField epsilon = sgsModel->epsilon(); does not return what you want. That epsilon is only the SGS epsilon. Since you do DNS, just apply the definition and you will be fine :-) Best,
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Alberto Passalacqua GeekoCFD - A free distribution based on openSUSE 64 bit with CFD tools, including OpenFOAM. Available as in both physical and virtual formats (current status: http://albertopassalacqua.com/?p=1541) OpenQBMM - An open-source implementation of quadrature-based moment methods. To obtain more accurate answers, please specify the version of OpenFOAM you are using. |
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July 9, 2016, 05:56 |
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#9 |
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Ehsan Asgari
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Hi,
This is an old thread, but I wonder if anyone has achieved a reliable method to calculate TKE dissipation?! Regards |
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March 22, 2022, 12:14 |
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#10 | |
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Quote:
Dear Johndeas, Did you find any way out ? I'm also stuck at the same state. |
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