# Maximum Number of Iterations Error

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August 2, 2012, 01:52
Maximum Number of Iterations Error
#1
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Join Date: Mar 2012
Posts: 27
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Hi Foamers,

I am reasonably new to OpenFOAM and I'm trying to model flow through a nozzle using a modified version of the rhoSimpleFoam solver, (rhoSimpleBaffleFoam). I have been getting the following error for weeks now and I can't figure out how to solve it. I have come across some people asking about the same or similar error on this forum, however I have not come across any solutions that fit my case.

If anyone can help, it will be greatly appreciated. I have attached a copy of my residuals if they are of use.
Time = 18350

GAMG: Solving for Ux, Initial residual = 0.0478601300291, Final residual = 6.19587887535e-05, No Iterations 1
GAMG: Solving for Uy, Initial residual = 0.0522063655834, Final residual = 6.37517577764e-05, No Iterations 1
GAMG: Solving for Uz, Initial residual = 0.000136930253207, Final residual = 2.36985398226e-07, No Iterations 1
GAMG: Solving for p, Initial residual = 9.51291539425e-05, Final residual = 9.48585631942e-07, No Iterations 7
time step continuity errors : sum local = 0.823069843414, global = 0.0336371330162, cumulative = -1.67778524427
rho max/min : 4.99999999998 0.100000000011
GAMG: Solving for h, Initial residual = 0.00429518647171, Final residual = 9.09102200735e-08, No Iterations 1
[0]
[0]
[0] --> FOAM FATAL ERROR:
[0] Maximum number of iterations exceeded
[0]
[0] From function specieThermo<Thermo>::T(scalar f, scalar T0, scalar (specieThermo<Thermo>::*F)(const scalar) const, scalar (specieThermo<Thermo>::*dFdT)(const scalar) const) const
[0] in file /home/opencfd/OpenFOAM/OpenFOAM-2.1.1/src/thermophysicalModels/specie/lnInclude/specieThermoI.H at line 69.
[0]
FOAM parallel run aborting
[0]
[0] #0 Foam::error:rintStack(Foam::Ostream&) in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
[0] #1 Foam::error::abort() in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
[0] #2 Foam::specieThermo<Foam::hConstThermo<Foam:erfec tGas> >::T(double, double, double (Foam::specieThermo<Foam::hConstThermo<Foam:erfe ctGas> >::*)(double) const, double (Foam::specieThermo<Foam::hConstThermo<Foam:erfe ctGas> >::*)(double) const, double (Foam::specieThermo<Foam::hConstThermo<Foam:erfe ctGas> >::*)(double) const) const in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libbasicThermophysicalModels.so"
[0] #3 Foam::hPsiThermo<Foam:ureMixture<Foam::constTran sport<Foam::specieThermo<Foam::hConstThermo<Foam:: perfectGas> > > > >::calculate() in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libbasicThermophysicalModels.so"
[0] #4 Foam::hPsiThermo<Foam:ureMixture<Foam::constTran sport<Foam::specieThermo<Foam::hConstThermo<Foam:: perfectGas> > > > >::correct() in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libbasicThermophysicalModels.so"
[0] #5
[0] in "/home/thomas/OpenFOAM/thomas-2.1.1/platforms/linux64GccDPOpt/bin/rhoSimplecBaffleFoam"
[0] #6 __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
[0] #7
[0] in "/home/thomas/OpenFOAM/thomas-2.1.1/platforms/linux64GccDPOpt/bin/rhoSimplecBaffleFoam"
--------------------------------------------------------------------------
MPI_ABORT was invoked on rank 0 in communicator MPI_COMM_WORLD
with errorcode 1.

NOTE: invoking MPI_ABORT causes Open MPI to kill all MPI processes.
You may or may not see output from other processes, depending on
exactly when Open MPI kills them.
--------------------------------------------------------------------------
--------------------------------------------------------------------------
mpirun has exited due to process rank 0 with PID 13578 on
node thomas-System-Product-Name exiting without calling "finalize". This may
have caused other processes in the application to be
terminated by signals sent by mpirun (as reported here).
--------------------------------------------------------------------------
Thomas
Attached Images
 rScBF_1_02.08.12.jpg (33.1 KB, 19 views)

 August 2, 2012, 15:44 #2 Super Moderator   Bruno Santos Join Date: Mar 2009 Location: Lisbon, Portugal Posts: 8,511 Blog Entries: 34 Rep Power: 86 Hi Thomas, This isn't in my level of experience with OpenFOAM, but with a nozzle flow... rho of 5.0... shouldn't you be using something like sonic*Foam? I remember reading about issues with sonicFoam as well... What's the Mach number you're getting? Will there be shock waves? Best regards, Bruno __________________ OpenFOAM: Frequently Asked Questions | Useful links for building and using Forum: How to ask for help | Posting code and output with [CODE] My to-do list and when I'll be able to come to the forum: http://wyldckat.github.io And please: Read this before sending private messages to me

 August 6, 2012, 17:49 #3 New Member   Join Date: Mar 2012 Posts: 27 Rep Power: 5 Hi Bruno, Sorry for the very slow reply. That density is entirely incorrect, it is calculated during a time when the residuals are a complete mess to say the least. The density should be in the range of 0.40 to 1.20. As for sonicFoam, the flow in this nozzle should not be sonic or nearing sonic. Although out of curiosity, do you know much about possible pressure waves reflecting back into my flow? Kind Regards, Tom

August 7, 2012, 06:52
#4
Super Moderator

Bruno Santos
Join Date: Mar 2009
Location: Lisbon, Portugal
Posts: 8,511
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Quote:
 Originally Posted by tomloh Although out of curiosity, do you know much about possible pressure waves reflecting back into my flow?
Unfortunately I don't know

From the error you're getting, it could also be a problem with the mesh - any errors or warnings from checkMesh? Are there enough cells in the smallest nozzle zone?

Nonetheless, reducing the speeds and pressure levels of the fluid flow, as well as using simpler geometries for diagnosing the problem, would be the next steps I would take.

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