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problems with wind tunnel

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Old   September 17, 2018, 09:07
Default problems with wind tunnel
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George Guimar„es Dias Siqueira
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Hello everyone!

My name is George and I need to simulate a flow in a wind tunnel using the simpleFoam solver, but the simulation has presented the following error:

#0 Foam::error:rintStack(Foam::Ostream&) at ??:?
#1 Foam::sigFpe::sigHandler(int) at ??:?
#2 ? in "/lib/x86_64-linux-gnu/libc.so.6"
#3 Foam::GaussSeidelSmoother::smooth(Foam::word const&, Foam::Field<double>&, Foam::lduMatrix const&, Foam::Field<double> const&, Foam::FieldField<Foam::Field, double> const&, Foam::UPtrList<Foam::lduInterfaceField const> const&, unsigned char, int) at ??:?
#4 Foam::GaussSeidelSmoother::smooth(Foam::Field<doub le>&, Foam::Field<double> const&, unsigned char, int) const at ??:?
#5 Foam::smoothSolver::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const at ??:?
#6 ? in "/opt/openfoam5/platforms/linux64GccDPInt32Opt/bin/simpleFoam"
#7 ? in "/opt/openfoam5/platforms/linux64GccDPInt32Opt/bin/simpleFoam"
#8 ? in "/opt/openfoam5/platforms/linux64GccDPInt32Opt/bin/simpleFoam"
#9 ? in "/opt/openfoam5/platforms/linux64GccDPInt32Opt/bin/simpleFoam"
#10 __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
#11 ? in "/opt/openfoam5/platforms/linux64GccDPInt32Opt/bin/simpleFoam"

I have no idea how to debug this!!! The flow is laminar, incompressible and the velocity is 13 m/s in the inlet. I do have to finish this for my graduate conclusion!!

Please, if anyone could help me will be very grateful!!

Thank you!
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Old   September 18, 2018, 03:39
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Robert
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Quote:
Originally Posted by gesiqueira View Post
#3 Foam::GaussSeidelSmoother::smooth(Foam::word const&, Foam::Field<double>&, Foam::lduMatrix const&, Foam::Field<double> const&, Foam::FieldField<Foam::Field, double> const&, Foam::UPtrList<Foam::lduInterfaceField const> const&, unsigned char, int) at ??:?
#4 Foam::GaussSeidelSmoother::smooth(Foam::Field<doub le>&, Foam::Field<double> const&, unsigned char, int) const at ??:?
#5 Foam::smoothSolver::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const at ??:?
Looks like a problem with solvers setup for U in fvSolution. If you post your fvSolutionDict i can take a closer look.

Tip: When posting the contents of your fvSolutionDict use the [*code][/code*] tags. Without the *. That keeps your post tidy.
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Old   September 19, 2018, 14:58
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George Guimar„es Dias Siqueira
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Hi RobertHB!!

Thank you very much for your answer! This is my fvSolution for this case:

solvers
{
p
{
solver PCG;
preconditioner DIC;
tolerance 1e-06;
relTol 0.05;
}

pFinal
{
$p;
tolerance 1e-06;
relTol 0;
}


U
{
solver smoothSolver;
smoother symGaussSeidel;
tolerance 1e-05;
relTol 0;
}
}

SIMPLE
{
nCorrectors 3;
nNonOrthogonalCorrectors 1;
pRefCell 0;
pRefValue 0;
}

I've already changed the "smoother" on velocity(U) to "GaussSeidel" but without success, too. If you have any idea, please tell me!! Thanks!!
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Old   September 19, 2018, 18:53
Default Solution Diverged
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Peter Brady
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Hi George,


Following on from Robert/s suggestion of the U solvers that may be a bit premature. Looking through the first two lines of the stack trace:


Code:
#0  Foam::error:printStack(Foam::Ostream&) at ??:?
#1  Foam::sigFpe::sigHandler(int) at ??:?
OpenFOAM threw a sigFpe error, which is a floating point error that I usually take as simply as the solver diverged or that I've really screwed up a mesh or input.


What is the quality of your mesh for this solution?


Are you running steady or transient?


Can you double check your boundary conditions and initial conditions?



Cheers,
-pete
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Old   September 19, 2018, 18:55
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Peter Brady
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Quote:
Originally Posted by pbrady2013 View Post
Are you running steady or transient?

Never mind this, I missed that you were running simpleFoam, so steady.
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Old   September 20, 2018, 05:17
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Robert
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Quote:
Originally Posted by pbrady2013 View Post
Code:
#0  Foam::error:printStack(Foam::Ostream&) at ??:?
#1  Foam::sigFpe::sigHandler(int) at ??:?
OpenFOAM threw a sigFpe error, which is a floating point error that I usually take as simply as the solver diverged or that I've really screwed up a mesh or input.
Checking your mesh twice is always a good idea. But if it really diverged, remember to use your relaxation factors to stabilize your solution. Usually p 0.3 to 0.4 and U 0.7 to 0.9 works quite well. You may also try my fvSolutionDict. Never had any problems with that one. If it still diverges, its the mesh
Attached Files
File Type: h fvOptions_MASTER.h (690 Bytes, 5 views)
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