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-   -   reactingFoam crashes mysteriously (http://www.cfd-online.com/Forums/openfoam-solving/86340-reactingfoam-crashes-mysteriously.html)

jose_rodrig March 20, 2011 09:30

reactingFoam crashes mysteriously
 
hi forum,

I am experiencing lots of instability with the solver reactionFoam with parallelization and they are not the janafthermo sort :(

My domain has around 260 000 elements and was divided in 32 domains for parallelization - divided as (16 2 1) to minimize proc borders. Im using the chemkin reader to read a single step combustion of CH4 oxidation in a GT combustor (diffusion flames). Inlet velocities are between 20 and 50 m/s.

I started fixing Courant No to 0.1. Everything looks good for about thousands of iterations but suddenly it crashes with a floating point exception. I say suddendly because I dont see a change in timestep or even the problematic janafThermo error message.

Also, it never crashes at the same timestep: if I simply restart the solver with the same parameters (no CourantNo change or any other) it will crash in a different timeStep.

It just goes!... as you can see in the following output after decreasing CourantNo to 0.035 (it still crashes!). I also attached a txt with the complete error message. Bellow the output i also posted the fvSolution and fvSchemes so you can take and criticize.

Thank you

Josť

[...]
DILUPBiCG: Solving for epsilon, Initial residual = 4.32044e-06, Final residual = 9.94436e-09, No Iterations 1
DILUPBiCG: Solving for k, Initial residual = 1.74131e-06, Final residual = 3.09184e-09, No Iterations 1
ExecutionTime = 161537 s ClockTime = 164174 s

Courant Number mean: 0.00125684 max: 0.0349221
deltaT = 3.80307e-07
Time = 0.3549768

Solving chemistry
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for Ux, Initial residual = 1.19096e-05, Final residual = 6.46123e-09, No Iterations 1
[24] #0 Foam::error::printStack(Foam::Ostream&)[25] #0 Foam::error::printStack(Foam::Ostream&)[26] #0 Foam::error::printStack(Foam::Ostream&)[27] #0
[...]


fvSolution

solvers
{
rho
{
solver PCG;
preconditioner DIC;
tolerance 1e-06;
relTol 0;
}
p
{
solver PCG;
preconditioner DIC;
tolerance 1e-6;
relTol 0.0;
}
pFinal
{
solver PCG;
preconditioner DIC;
tolerance 1e-6;
relTol 0.0;
}

"(U|Yi|hs|k|epsilon)"
{
solver PBiCG;
preconditioner DILU;
tolerance 1e-06;
relTol 0;
}
}

PISO
{
nCorrectors 3;
nNonOrthogonalCorrectors 6;
}
relaxationFactors
{
rho 0.6;
U 0.6;
pFinal 0.4;
p 0.4;
k 0.6;
epsilon 0.6;
hs 0.6;
T 0.6;
}

fvSchemes

ddtSchemes
{
default Euler; //CrankNicholson 1; //Euler;
}

gradSchemes
{
default Gauss linear;
grad(p) Gauss linear;
}

divSchemes
{
default none;

div(phi,U) Gauss limitedLinearV 1;
div(phi,Yi_h) Gauss limitedLinear01 1;
div(phi,hs) Gauss limitedLinear 1;
div(phiU,p) Gauss limitedLinear 1;
div(phid,p) Gauss limitedLinear 1;
div(phi,epsilon) Gauss limitedLinear 1;
div(phi,k) Gauss limitedLinear 1;
div((muEff*dev2(grad(U).T()))) Gauss linear;
}

laplacianSchemes
{
default Gauss linear uncorrected;
laplacian(muEff,U) Gauss linear uncorrected;
laplacian(mut,U) Gauss linear uncorrected;
laplacian(DkEff,k) Gauss linear uncorrected;
laplacian(DepsilonEff,epsilon) Gauss linear uncorrected;
laplacian((rho*(1|A(U))),p) Gauss linear uncorrected;
laplacian(alphaEff,hs) Gauss linear uncorrected;
}

interpolationSchemes
{
default linear;
}

snGradSchemes
{
default uncorrected;
}

fluxRequired
{
default no;
p;
}

jose_rodrig March 20, 2011 10:01

error log
 
1 Attachment(s)
sorry, forgot the attachment

alberto March 21, 2011 04:52

Hi,

does it always crash on the same equation, namely Uy?

I have a similar problem with another solver, if I use PBiCG solvers with DILU preconditioner. You might want to try with another type of linear solver for that equation to verify if it still happens.

Best,

jose_rodrig March 21, 2011 05:52

Hi alberto,

No, it crashes pretty randomly.

Actually, my simulation crashes in two ways:

a) mpi sends a message of "floating point exception" error (signal 8);

b) mpi sends a message of "Hang Up" (signal 1)

Are these 2 types of error related?

A workmate told me that openFoam sometimes hangs on opensuse (i am using 11.4): do you think this might be the problem?

alberto March 21, 2011 06:05

Quote:

Originally Posted by jose_rodrig (Post 300315)
Hi alberto,

No, it crashes pretty randomly.

Actually, my simulation crashes in two ways:

a) mpi sends a message of "floating point exception" error (signal 8);

b) mpi sends a message of "Hang Up" (signal 1)

Are these 2 types of error related?

A workmate told me that openFoam sometimes hangs on opensuse (i am using 11.4): do you think this might be the problem?

I am using the same distribution, but I use openMPI from the ThirdParty package, even though I use the system gcc compiler (4.5), so I would exclude distro-specific problems. I also observe a similar behaviour on RHEL 5.2.

Out of curiosity, do you use the system OpenMPI, the one in ThirdParty or a different version?

Best,

jose_rodrig March 21, 2011 06:15

hi,

I am using openMPI 1.4.1 from the Third Party package. I've compiled OpenFOAM myself.

regards

jose

alberto March 21, 2011 06:35

OK, we are using exactly the same configuration then. I am going to test a different MPI implementation to see if it might depend on that, and I'll let you know.

Maybe you should report it as a bug however. I reported mine, but we believed it was specific to the solver. You just confirmed it is not.

Best,

jose_rodrig March 21, 2011 08:32

Ok, I ll report my problem ASAP.

One more thing, I d like you to take a look in my other post. It is not related to this one but is also turning my head around.

Here is the link http://www.cfd-online.com/Forums/ope...dary-face.html

Regards

achinta June 26, 2012 04:42

hello reactingFoamers :),
i am new to reactingFoam solver. I am first interested in mixing of gases(without reaction). Some threads suggested reactingFoam (with chemistry switched off). I ran the solver and it crashed after 16 milliseconds. Here is my set-up
------------------------
chemistry properties file
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
psiChemistryModel ODEChemistryModel<gasThermoPhysics>;

chemistry off; // switch off chemistry

chemistrySolver ode;

initialChemicalTimeStep 1e-07;

sequentialCoeffs
{
cTauChem 0.001;
}

EulerImplicitCoeffs
{
cTauChem 0.05;
equilibriumRateLimiter off;
}

odeCoeffs
{
solver SIBS;
eps 0.05;
scale 1;
}
// ************************************************** *********************** //
Combustion properties file
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
combustionModel PaSR<psiChemistryCombustionModel>;

active false; //combustion switched off

infinitelyFastChemistryCoeffs
{
C 10.0;
}

PaSRCoeffs
{
Cmix Cmix [ 0 0 0 0 0 0 0 ] 0.1;
turbulentReaction off; //switched off
}
// ************************************************** *********************** //
reactions file
-------------
species
(
O2
H2O
CH4
CO2
N2
);

reactions
{
methaneReaction
{
type irreversibleArrheniusReaction;
reaction "CH4 + 2O2 = CO2 + 2H2O";
A 5.2e16;
beta 0;
Ta 14906;
}
}
-----------------
Thermophysical properties file
----------------------
thermoType hsPsiMixtureThermo<reactingMixture<gasThermoPhysic s>>;

inertSpecie N2;

chemistryReader foamChemistryReader;

foamChemistryFile "$FOAM_CASE/constant/reactions";

foamChemistryThermoFile "$FOAM_CASE/constant/thermo.compressibleGas";
--------------------

i am using SST turbulence model. Below are the boundary conditions:
------------
mut and alphat
internalField uniform 0;

boundaryField
{
INLET
{
type fixedValue;
value uniform 0;
}
OUTLET
{
type zeroGradient;
}

mut for walls
type mutUSpaldingWallFunction;
value uniform 0;

alphat for walls
type alphatWallFunction;
Prt 0.85;
value uniform 0;
-----------
T:
internalField uniform 550;

boundaryField
{
INLET_FUEL
{
type fixedValue;
value uniform 293;
}

INLET_AIR
{
type fixedValue;
value uniform 550;
}

OUTLET
{
type zeroGradient;
}

WALL
{
type zeroGradient;
}
-----------------
I don't think there could be problems with boundary conditions of U,CH4,N2,O2,k,omega and Ydefault and i won't write them here as it will lengthen the post.

There error message seems to do something with mut wall function and happens because its diverging-Tempearure is going out of range. But the Courant number is below 1. Probably, i have to improve my fvSchemes and fvSolution
:
----------
fvSchemes
ddtSchemes
{
default backward;
}

gradSchemes
{
default Gauss linear;
}

divSchemes
{
default none;
div(phi,U) Gauss linearUpwindV grad(U);
div(phi,Yi_h) Gauss limitedLinear01 1;
div(phi,h) Gauss limitedLinear 1;
div(phi,K) Gauss limitedLinear 1;
div(phid,p) Gauss limitedLinear 1;
div(phi,omega) Gauss limitedLinear 1;
div(phi,k) Gauss limitedLinear 1;
div((muEff*dev2(T(grad(U))))) Gauss linear;
}
laplacianSchemes
{
default Gauss linear corrected;
}

interpolationSchemes
{
default linear;
}

snGradSchemes
{
default corrected;
}

fluxRequired
{
default no;
p;
}
------------
fvSolution
solvers
{
rho
{
solver PCG;
preconditioner DIC;
tolerance 1e-06;
relTol 0.05;
}

rhoFinal
{
$rho;
tolerance 1e-06;
relTol 0;
}

p
{
solver PCG;
preconditioner DIC;
tolerance 1e-6;
relTol 0.05;
}

pFinal
{
$p;
tolerance 1e-6;
relTol 0.0;
}

"(U|hs||k|omega)"
{
solver PBiCG;
preconditioner DILU;
tolerance 1e-06;
relTol 0.05;
}

"(U|hs||k|omega)Final"
{
solver PBiCG;
preconditioner DILU;
tolerance 1e-06;
relTol 0;
}

Yi
{
$hsFinal;
}
}

PIMPLE
{
momentumPredictor no;
nOuterCorrectors 1;
nCorrectors 2;
nNonOrthogonalCorrectors 1;
}
-----------------------
I kindly request OpeFOAM experts to help me. I have spent lot of time on this problem. I didn't find many tutorials about reacting foam and i am not able to proceed with my simulation.

Regards,
Achinta


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