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November 20, 2009, 11:03 
pisoFoam Error

#1 
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Hej all,
I recieve this error when I execute pisoFoam: __________________________________________________ ____________________ Calculating averages Time = 0.00142 Courant Number mean: 3.72507e+52 max: 1.36418e+54 DILUPBiCG: Solving for Ux, Initial residual = 0.555198, Final residual = 1.81207e06, No Iterations 35 DILUPBiCG: Solving for Uy, Initial residual = 0.882337, Final residual = 2.82071e06, No Iterations 36 DILUPBiCG: Solving for Uz, Initial residual = 0.959453, Final residual = 2.3849e06, No Iterations 29 DICPCG: Solving for p, Initial residual = 0.685706, Final residual = 0.0341773, No Iterations 70 time step continuity errors : sum local = 2.65701e+50, global = 1.48284e+49, cumulative = 1.38529e+49 DICPCG: Solving for p, Initial residual = 0.684507, Final residual = 9.50829e07, No Iterations 171 time step continuity errors : sum local = 2.06627e+46, global = 1.52172e+44, cumulative = 1.38528e+49 DILUPBiCG: Solving for k, Initial residual = 0.88271, Final residual = 7.51988e06, No Iterations 6 bounding k, min: 3.72039e+117 max: 7.6031e+117 average: 2.9493e+116 ExecutionTime = 164.59 s ClockTime = 165 s Calculating averages Time = 0.00143 Courant Number mean: 8.88307e+51 max: 2.84151e+53 DILUPBiCG: Solving for Ux, Initial residual = 0.856534, Final residual = 7.94225e06, No Iterations 39 DILUPBiCG: Solving for Uy, Initial residual = 0.826641, Final residual = 9.82446e06, No Iterations 37 DILUPBiCG: Solving for Uz, Initial residual = 0.6356, Final residual = 6.89001e06, No Iterations 35 DICPCG: Solving for p, Initial residual = 0.702043, Final residual = 0.0343882, No Iterations 78 time step continuity errors : sum local = 6.28092e+51, global = 2.13804e+49, cumulative = 7.5276e+48 DICPCG: Solving for p, Initial residual = 0.778709, Final residual = 8.64955e07, No Iterations 171 time step continuity errors : sum local = 5.07704e+47, global = 7.17519e+44, cumulative = 7.52832e+48 #0 Foam::error:rintStack(Foam::Ostream&) in "/opt/OpenFOAM/OpenFOAM1.6/lib/linux64GccDPOpt/libOpenFOAM.so" #1 Foam::sigFpe::sigFpeHandler(int) in "/opt/OpenFOAM/OpenFOAM1.6/lib/linux64GccDPOpt/libOpenFOAM.so" #2 ?? in "/lib/libc.so.6" #3 Foam::PBiCG::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const in "/opt/OpenFOAM/OpenFOAM1.6/lib/linux64GccDPOpt/libOpenFOAM.so" #4 Foam::fvMatrix<double>::solve(Foam::dictionary const&) in "/opt/OpenFOAM/OpenFOAM1.6/lib/linux64GccDPOpt/libfiniteVolume.so" #5 Foam::incompressible::LESModels:neEqEddy::correc t(Foam::tmp<Foam::GeometricField<Foam::Tensor<doub le>, Foam::fvPatchField, Foam::volMesh> > const&) in "/opt/OpenFOAM/OpenFOAM1.6/lib/linux64GccDPOpt/libincompressibleLESModels.so" #6 Foam::incompressible::LESModel::correct() in "/opt/OpenFOAM/OpenFOAM1.6/lib/linux64GccDPOpt/libincompressibleLESModels.so" #7 main in "/opt/OpenFOAM/OpenFOAM1.6/applications/bin/linux64GccDPOpt/pisoFoam" #8 __libc_start_main in "/lib/libc.so.6" #9 _start at /usr/src/packages/BUILD/glibc2.9/csu/../sysdeps/x86_64/elf/start.S:116 GleitkommaAusnahme __________________________________________________ ____________________ It's running for a while and then it crashes. Could it be, that my Courant Number is much to hight? Or isn't there enough memory? Have I nice weekend, Erik PS: I'll only be back on monday :) 

November 20, 2009, 15:23 

#2 
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Anton Kidess
Join Date: May 2009
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Yes, your simulations are diverging and the Courant number gets way out of hand. As usual, check your boundary and initial conditions, and then your numerical parameters. Time step looks like it's pretty small already, so I'm assuming that's not your problem.


November 23, 2009, 08:49 

#3 
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Hi akidess,
thx for your help. The courant number depends on the speed, the timestep and the cell size, right? But how can I improve the courant number? I have already tried even smaler time steps and also a smaler inital speed U, but with the same result. What else could I do to make the calculation converging? 

November 23, 2009, 19:13 

#4  
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Alberto Passalacqua
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Quote:
About your case, it would be useful to know some more details on the case and the numerical setup (fvSchemes, essentially). Best,
__________________
Alberto Passalacqua GeekoCFD  A free distribution based on openSUSE 64 bit with CFD tools, including OpenFOAM. Available as in both physical and virtual formats. OpenQBMM  An opensource implementation of quadraturebased moment methods. To obtain more accurate answers, please specify the version of OpenFOAM you are using. Last edited by alberto; November 23, 2009 at 19:14. Reason: Corrected link 

November 23, 2009, 20:53 

#5  
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Anton Kidess
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Quote:


November 24, 2009, 04:33 

#6  
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Thank you very much, I really appreciate your help!
My case is about a pipe flow with a tube in the middle. This is my fvSchemes file: Quote:
There are the initial conditions for U: Quote:
Quote:
Quote:
Sorry for the long post. Last edited by sErik; November 24, 2009 at 06:07. 

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