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-   -   High aspect ratio cells with checkmesh (http://www.cfd-online.com/Forums/openfoam-solving/58262-high-aspect-ratio-cells-checkmesh.html)

gian_ing November 18, 2008 12:00

I tried another simulation usi
 
I tried another simulation using simplefoam with a new mesh and NO high aspect ratio cells.
The same error results.
I paste it here.
I don't know why all the residuals diverge.


DILUPBiCG: Solving for Ux, Initial residual = 0.999988, Final residual = 8.45492e-09, No Iterations 78
DILUPBiCG: Solving for Uy, Initial residual = 0.99999, Final residual = 6.45854e-09, No Iterations 77
DICPCG: Solving for p, Initial residual = 0.0766972, Final residual = 4.87576e-09, No Iterations 408
DICPCG: Solving for p, Initial residual = 0.377693, Final residual = 9.83582e-09, No Iterations 5
time step continuity errors : sum local = 3.3791e+21, global = -1.23254e+21, cumulative = -1.23254e+21
ExecutionTime = 2.33 s ClockTime = 3 s

Time = 0.9

DILUPBiCG: Solving for Ux, Initial residual = 0.999953, Final residual = 6.14167e-09, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 0.999839, Final residual = 1.51288e-09, No Iterations 1
#0 Foam::error::printStack(Foam:http://www.cfd-online.com/OpenFOAM_D...part/proud.gifstream&) in "/home/cfduser/OpenFOAM/OpenFOAM-1.5/lib/linux64GccDPOpt/libOpenFOAM.so"
#1 Foam::sigFpe::sigFpeHandler(int) in "/home/cfduser/OpenFOAM/OpenFOAM-1.5/lib/linux64GccDPOpt/libOpenFOAM.so"
#2 ?? in "/lib/libc.so.6"
#3 Foam::DICPreconditioner::calcReciprocalD(Foam::Fie ld<double>&, Foam::lduMatrix const&) in "/home/cfduser/OpenFOAM/OpenFOAM-1.5/lib/linux64GccDPOpt/libOpenFOAM.so"
#4 Foam::DICPreconditioner::DICPreconditioner(Foam::l duMatrix::solver const&, Foam::Istream&) in "/home/cfduser/OpenFOAM/OpenFOAM-1.5/lib/linux64GccDPOpt/libOpenFOAM.so"
#5 Foam::lduMatrix::preconditioner::addsymMatrixConst ructorToTable<foam::dicprecond itioner>::New(Foam::lduMatrix::solver const&, Foam::Istream&) in "/home/cfduser/OpenFOAM/OpenFOAM-1.5/lib/linux64GccDPOpt/libOpenFOAM.so"
#6 Foam::lduMatrix::preconditioner::New(Foam::lduMatr ix::solver const&, Foam::Istream&) in "/home/cfduser/OpenFOAM/OpenFOAM-1.5/lib/linux64GccDPOpt/libOpenFOAM.so"
#7 Foam::PCG::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const in "/home/cfduser/OpenFOAM/OpenFOAM-1.5/lib/linux64GccDPOpt/libOpenFOAM.so"
#8 Foam::fvMatrix<double>::solve(Foam::Istream&) in "/home/cfduser/OpenFOAM/OpenFOAM-1.5/lib/linux64GccDPOpt/libfiniteVolume.so"
#9 main in "/home/cfduser/OpenFOAM/OpenFOAM-1.5/applications/bin/linux64GccDPOpt/simpleFoam "
#10 __libc_start_main in "/lib/libc.so.6"
#11 Foam::regIOobject::readIfModified() in "/home/cfduser/OpenFOAM/OpenFOAM-1.5/applications/bin/linux64GccDPOpt/simpleFoam "
Floating point exception

santos November 19, 2008 10:36

Just a wild guess: are 'up' an
 
Just a wild guess: are 'up' and 'down' patches supposed to have Ux=1, or are they supposed to be symmetry planes?

Regards,
Jose Santos

antonio_ing November 20, 2008 06:40

I guess these are the BC at in
 
I guess these are the BC at infinity (something like the inlet)

gian_ing November 20, 2008 12:39

Antonio's guess was right. Th
 
Antonio's guess was right.
They're not simmetry planes, they're something like a Ux at infinity.

Regards

naish November 27, 2008 07:10

Hi Gianluca I have te same p
 
Hi Gianluca
I have te same problems, please can you explain how do you fixed your problem.
I do not understand " no symmetry planes / Ux at infinity"

Regards

gian_ing December 2, 2008 10:45

Initially I set a simmetry pla
 
Initially I set a simmetry plane like cylinder but that was not a solution.
For my case the problem was not in the boundary conditions but I was mistaken setting a "laminar" condition in RASproperties file with a high Reynolds number simulation.
That made the code go crazy.
The other settings should be ok.

If you need some more clarification let me know but I'm not an expert.

Good luck
Regards


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