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-   -   bounded Gauss and normal Gauss question (http://www.cfd-online.com/Forums/openfoam/119195-bounded-gauss-normal-gauss-question.html)

Tobi June 11, 2013 16:22

bounded Gauss and normal Gauss question
 
2 Attachment(s)
Hi all,

I modifyed the flamelet solver (libOpenSmoke) and used the nice feature in the OF 2.2.x for the equations for

  • mixture fraction Z
  • variance of mixture fraction Z
  • enthalpy H


In the old code I implemented the Sp term in the code:


Code:

        (
            fvm::div(phi, Z)
                    - fvm::Sp(fvc::div(phi), Z)       
                        - fvm::laplacian(turbulence->muEff()/sigmat, Z)
        )

In the new version I used it without:

Code:

        (
            fvm::div(phi, Z)   
                        - fvm::laplacian(turbulence->muEff()/sigmat, Z)
        )

but therefor I added bounded schemes (fvSchemes):
Code:

    div(phi,H)          bounded Gauss limitedLinear 1;
    div(phi,Z)          bounded Gauss limitedLimitedLinear 1 0 1;
    div(phi,Zvar)      bounded Gauss limitedLimitedLinear 1 0 0.25;

This settings give an identical simulation and the validation was 1:1.

OF was warning like:
Code:

--> FOAM Warning :
    From function gaussConvectionScheme
    in file finiteVolume/convectionSchemes/gaussConvectionScheme/gaussConvectionScheme.H at line 123
    Reading "/home/shor-ty/OpenFOAM/shor-ty-2.2.x/flameletModel-2.2.x/tutorials/Sandia_COH2N2/system/fvSchemes.divSchemes.div(phi,U)" at line 30
    Unbounded 'Gauss' div scheme used in steady-state solver, use 'bounded Gauss' to ensure boundedness.
    To remove this warning switch off 'boundedGauss' in "/home/shor-ty/OpenFOAM/OpenFOAM-2.2.x/etc/controlDict"
smoothSolver:  Solving for Ux, Initial residual = 0.00265791, Final residual = 1.16588e-05, No Iterations 2
smoothSolver:  Solving for Uy, Initial residual = 3.76559e-05, Final residual = 1.86524e-07, No Iterations 2
smoothSolver:  Solving for Uz, Initial residual = 0.0056559, Final residual = 4.24363e-05, No Iterations 2
GAMG:  Solving for p, Initial residual = 0.00227516, Final residual = 7.45788e-05, No Iterations 2
time step continuity errors : sum local = 0.0252954, global = 9.16694e-05, cumulative = -2.81028
rho max/min : 1.21084 0.176765
smoothSolver:  Solving for Z, Initial residual = 5.02383e-05, Final residual = 6.15323e-07, No Iterations 2
smoothSolver:  Solving for Zvar, Initial residual = 4.07254e-05, Final residual = 4.37422e-08, No Iterations 2
smoothSolver:  Solving for H, Initial residual = 5.61876e-05, Final residual = 7.14374e-07, No Iterations 2
--> FOAM Warning :
    From function gaussConvectionScheme
    in file finiteVolume/convectionSchemes/gaussConvectionScheme/gaussConvectionScheme.H at line 123
    Reading "/home/shor-ty/OpenFOAM/shor-ty-2.2.x/flameletModel-2.2.x/tutorials/Sandia_COH2N2/system/fvSchemes.divSchemes.div(phi,epsilon)" at line 31
    Unbounded 'Gauss' div scheme used in steady-state solver, use 'bounded Gauss' to ensure boundedness.
    To remove this warning switch off 'boundedGauss' in "/home/shor-ty/OpenFOAM/OpenFOAM-2.2.x/etc/controlDict"
smoothSolver:  Solving for epsilon, Initial residual = 0.00011511, Final residual = 5.69949e-07, No Iterations 2
--> FOAM Warning :
    From function gaussConvectionScheme
    in file finiteVolume/convectionSchemes/gaussConvectionScheme/gaussConvectionScheme.H at line 123
    Reading "/home/shor-ty/OpenFOAM/shor-ty-2.2.x/flameletModel-2.2.x/tutorials/Sandia_COH2N2/system/fvSchemes.divSchemes.div(phi,k)" at line 32
    Unbounded 'Gauss' div scheme used in steady-state solver, use 'bounded Gauss' to ensure boundedness.
    To remove this warning switch off 'boundedGauss' in "/home/shor-ty/OpenFOAM/OpenFOAM-2.2.x/etc/controlDict"
smoothSolver:  Solving for k, Initial residual = 0.000112566, Final residual = 8.72544e-07, No Iterations 2
ExecutionTime = 651.17 s  ClockTime = 654 s

and so I used bounded schemes for all div equations.
If I do that, I get a strange solution (picture).

can someone tell why the values are so different?

picture bound: all schemes are bounded Gauss
picture unbound: only Z,Zvar,H are bounded

Thanks in advance,
Tobi

Tobi June 12, 2013 03:42

Hi all,

maybe I made a mistake due to too less time and very tierd. I ll have a look at that the next days and Keep you posted!

Tushar@cfd June 18, 2013 00:35

Code:

    div(phi,H)          bounded Gauss limitedLinear 1;   
    div(phi,Z)          bounded Gauss limitedLimitedLinear 1 0 1;   
    div(phi,Zvar)      bounded Gauss limitedLimitedLinear 1 0 0.25;

Hello,

I have a doubt, I am not sure whether I am right or wrong.

I think when you are using the keyword "bounded" and "limited" together the warning might have displayed in the terminal. May be with any other bounded scheme (i.e., instead of limited) this will go off.


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