[amin144]

my problem solved by using "sudo bash" in my account terminal
now when I type these two lines:
cd src/transportModels/viscoelastic/ wmake libso && cd -
cd applications/solvers/viscoelastic/viscoelasticFluidFoam/ wmake && cd -

it says:
is up to date

but when I want to run the tutorials, It say:
Starting time loop

Courant Number mean: 6.54561e-07 max: 1.84912e-05
deltaT = 1.19999e-05
Time = 1.19999e-05



--> FOAM FATAL IO ERROR:
Unknown asymmetric matrix solver BiCGStab

Valid asymmetric matrix solvers are :

4
(
BICCG
GAMG
PBiCG
smoothSolver
)


file: /home/amin/OpenFOAM/amin-2.1.1/run/tutorials/viscoelastic/viscoelasticFluidFoam/Oldroyd-B/system/fvSolution::solvers::U from line 47 to line 56.

From function lduMatrix::solver::New
in file matrices/lduMatrix/lduMatrix/lduMatrixSolver.C at line 106.

FOAM exiting


I don't know Can I see I have new working OpenFOAM at last?

[amin144]

I understand the problem!

It seems I should modify the tutorials according to OF2.1.1
But I can't do it completely because I don't know meaning of many expressions.
I can run the case but I don't know what is the best solver and preconditioner to use instead of old ones???
Anybody could upload a modified tutorial?

TanX very much

[sandipd]

Hay, you just refer the previous posts by Jovani and ata; i.e. you need make changes in fvSolution to change the solvers and preconditioner for p, U and tau.
1) For pressure you can use solver 'PCG', preconditioner 'DIC'
2) For U and tau use the solver 'PBiCG' and preconditioner 'DILU'..

Re,

[sandipd]

Hi friends,

Anybody has worked for a blow molding problem using openFoam ( specially viscoelasticFluidFoam)? .. I am working on it, and needs the support for implementation with openfoam..

Thanks & Regards,

Sandip.

[amin144]

Hi dear FOAMers

I have basic questions, maybe very amateur questions.
1)What is tau in models like Giesekus? It's total stress or extra stress?

2)If I want calculate wall stress, can I use the utility "wallShearStress" or this give me only Newtonian part of stress?

3)what is best way to calculate eta and shear rate and plot diagram of them according to each other?


Best regards,
Amin

[adambarfi]

Hi everybody,

I'm trying to solve natural convection in a viscoelastic fluid. I added the temperature equation and Buossinesq assumption to the viscoelasticFluidFoam, but when I ran it after sum iteration the below errors appeared:

DICPCG:  Solving for p, Initial residual = 1, Final residual =  6.72375e-08, No Iterations 62 
time step continuity errors : sum local =  4.77002e+25, global = -9.93552e+15, cumulative = -9.93552e+15 Model mode  1 
#0  Foam::error::printStack(Foam::Ostream&) in  "/home/mostafa/OpenFOAM/OpenFOAM-2.1.0/platforms/linuxGccDPOpt/lib/libOpenFOAM.so"  #1  
Foam::sigFpe::sigHandler(int) in "/home/mostafa/OpenFOAM/OpenFOAM-2.1.0/platforms/linuxGccDPOpt/lib/libOpenFOAM.so" 
#2  Uninterpreted:  
#3  Foam::PBiCG::solve(Foam::Field<double>&,  Foam::Field<double> const&, unsigned char) const in  "/home/mostafa/OpenFOAM/OpenFOAM-2.1.0/platforms/linuxGccDPOpt/lib/libOpenFOAM.so"  
#4  Foam::fvMatrix<Foam::SymmTensor<double>  >::solve(Foam::dictionary const&) in  "/home/mostafa/OpenFOAM/OpenFOAM-2.1.0/platforms/linuxGccDPOpt/lib/libviscoelasticTransportModels.so"  
#5  Foam::fvMatrix<Foam::SymmTensor<double> >::solve() in  "/home/mostafa/OpenFOAM/OpenFOAM-2.1.0/platforms/linuxGccDPOpt/lib/libviscoelasticTransportModels.so"  
#6  Foam::Giesekus::correct() in  "/home/mostafa/OpenFOAM/OpenFOAM-2.1.0/platforms/linuxGccDPOpt/lib/libviscoelasticTransportModels.so"  
#7  Foam::multiMode::correct() in  "/home/mostafa/OpenFOAM/OpenFOAM-2.1.0/platforms/linuxGccDPOpt/lib/libviscoelasticTransportModels.so"  
#8  Foam::viscoelasticModel::correct() in  "/home/mostafa/OpenFOAM/OpenFOAM-2.1.0/platforms/linuxGccDPOpt/lib/libviscoelasticTransportModels.so"  
#9    in "/home/mostafa/OpenFOAM/OpenFOAM-2.1.0/platforms/linuxGccDPOpt/bin/BuoyantBoussinesqViscoelasticFluidFoam" 
#10  __libc_start_main in "/lib/i386-linux-gnu/libc.so.6" #11    in  "/home/mostafa/OpenFOAM/OpenFOAM-2.1.0/platforms/linuxGccDPOpt/bin/BuoyantBoussinesqViscoelasticFluidFoam"  
Floating point exception

anybody knows how can I solve this problem?

[ata]

Hi
To Amin
1- AFAIK it is extra stress tensor.
3-You can calculate them using fvc:: and write them in a file and then plot it.
To Adambarfi
Examine my previous mentioned tips one by one.

[adambarfi]

Dear Ata,

which tips?
I attach the fvScheme and fvSolution for you. please comment on them.

thank you so much.

[ata]

Hi
How much is your max. Courant number and delta T?

[adambarfi]

Originally Posted by ata

Hi
How much is your max. Courant number and delta T?

ohh!!! my God!!
the max Cournat number was 0.8.
I decreased it to 0.25 and my solver worked correctly. the delta T was 1.

Thank you Ata, I had forgotten the Cournat number, completely.

[amin144]

Originally Posted by ata

Hi
To Amin
1- AFAIK it is extra stress tensor.
3-You can calculate them using fvc:: and write them in a file and then plot it.
To Adambarfi
Examine my previous mentioned tips one by one.

Dear Ata!
TanX for your quick reply.

Don't you know anuthing about WallShearStress?
If I want total shear stress, would I sum shear stress given from wallShearStress utility and what is in tau matrix?

I thought everybody know about computing wall shear stress very well and it' easy problem.

[ata]

Hi Amin
Unfortunately I have no experience in your problem. See the OF utilities. May be you can find a useful function.

[amin144]

Originally Posted by ata

Hi Amin
Unfortunately I have no experience in your problem. See the OF utilities. May be you can find a useful function.

TANX very much dear Ata
I appreciate your attention
I wish Jovani come here soon

[jovani]

Hi Amin,

I never needed this yet. A possible way: If you have solvent viscosity (etaS != 0) sum up the solvent and polymer stress to get the total stress. The polymer is just tau returned back by the solver. So, create an utility to calculate solvent stress and sum up it with polymer stress and return the total stress as a post processing stage. When you got the total stress adapt the wallShearStress utility to return the wall shear stress for tauTotal instead of Reff.

Regards,
Jovani

[adambarfi]

Hi to all,

anybody knows why my max. velocity in natural convection increased instead of dropping when I increased the relaxation time in Giesekus model?

thank you.

[samegypt]

Dear Foamers

Kindly, I have two question,

1- if I want to turn-Off the stabilising technique (DEVSS) used in the viscoelasticFluidFoam solver , I will go to the the viscoelastic model for example the Oldroyd_B Model to modify the following lines (located at /OpenFOAM/OpenFOAM-2.1.0/src/transportModels/viscoelastic/viscoelasticLaws/Oldroyd-B/Oldroyd_B.C), Is that corrector wrong?
---------------------------------------------------------------------------------------------------------------------
Foam::tmp<Foam::fvVectorMatrix>
Foam::Oldroyd_B::divTau(volVectorField& U) const
{
dimensionedScalar etaPEff = 0; //turn-On DEVSS, put etaPEff = etaP_
return
(
fvc::div(tau_/rho_, "div(tau)")
- fvc::laplacian(etaPEff/rho_, U, "laplacian(etaPEff,U)")
+ fvm::laplacian( (etaPEff + etaS_)/rho_, U, "laplacian(etaPEff+etaS,U)")
);
}
---------------------------------------------------------------------------------------------------------------

2- For activating the above lines in the Oldroyd_B.C Model, I will only save and close the file. Is that enough? or I also need to make recompilation of Openfoam directory by using the command line ./Allwmake


Thanks

[ata]

Hi
I think you only need to recompile oldroyd-b model library.

[samegypt]

Originally Posted by ata

Hi
I think you only need to recompile oldroyd-b model library.

Dear Ata, thanks for your reply,
Please, what is the steps to recompile the oldroyd-b model library?
thanks

[ata]

Hi
Jovani has replied to this question in the previous posts (I asked from him) in this thread. See that.

[samegypt]

Originally Posted by jovani

First thank you Hrvoje!!

EVSS is very different, once is needed a change on the constitutive equation (in my master thesis is very clear this point).
And more, I tested the EVSS methodology too (I have an old solver with this implementation), but really what you have in hands
today with viscoelasticFluidFoam is much higher.

Dear Jovani,

I am interested to implementation the EVSS methodology in my viscoelastic code, is it possible to ask you to send me your old EVSS solver.

regards,
Samir