CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > OpenFOAM Running, Solving & CFD

pisoFoam Error

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   November 20, 2009, 11:03
Default pisoFoam Error
  #1
Member
 
Join Date: Nov 2009
Location: Munich
Posts: 43
Rep Power: 7
sErik is on a distinguished road
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 = 1.81207e-06, No Iterations 35
DILUPBiCG: Solving for Uy, Initial residual = 0.882337, Final residual = 2.82071e-06, No Iterations 36
DILUPBiCG: Solving for Uz, Initial residual = 0.959453, Final residual = 2.3849e-06, 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 = 9.50829e-07, 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 = 7.51988e-06, 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 = 7.94225e-06, No Iterations 39
DILUPBiCG: Solving for Uy, Initial residual = 0.826641, Final residual = 9.82446e-06, No Iterations 37
DILUPBiCG: Solving for Uz, Initial residual = 0.6356, Final residual = 6.89001e-06, 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 = 8.64955e-07, 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/OpenFOAM-1.6/lib/linux64GccDPOpt/libOpenFOAM.so"
#1 Foam::sigFpe::sigFpeHandler(int) in "/opt/OpenFOAM/OpenFOAM-1.6/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/OpenFOAM-1.6/lib/linux64GccDPOpt/libOpenFOAM.so"
#4 Foam::fvMatrix<double>::solve(Foam::dictionary const&) in "/opt/OpenFOAM/OpenFOAM-1.6/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/OpenFOAM-1.6/lib/linux64GccDPOpt/libincompressibleLESModels.so"
#6 Foam::incompressible::LESModel::correct() in "/opt/OpenFOAM/OpenFOAM-1.6/lib/linux64GccDPOpt/libincompressibleLESModels.so"
#7 main in "/opt/OpenFOAM/OpenFOAM-1.6/applications/bin/linux64GccDPOpt/pisoFoam"
#8 __libc_start_main in "/lib/libc.so.6"
#9 _start at /usr/src/packages/BUILD/glibc-2.9/csu/../sysdeps/x86_64/elf/start.S:116
Gleitkomma-Ausnahme

__________________________________________________ ____________________

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 :-)
sErik is offline   Reply With Quote

Old   November 20, 2009, 15:23
Default
  #2
Senior Member
 
akidess's Avatar
 
Anton Kidess
Join Date: May 2009
Location: Delft, Netherlands
Posts: 919
Rep Power: 16
akidess will become famous soon enough
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.
akidess is offline   Reply With Quote

Old   November 23, 2009, 08:49
Default
  #3
Member
 
Join Date: Nov 2009
Location: Munich
Posts: 43
Rep Power: 7
sErik is on a distinguished road
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?
sErik is offline   Reply With Quote

Old   November 23, 2009, 19:13
Default
  #4
Senior Member
 
Alberto Passalacqua
Join Date: Mar 2009
Location: Ames, Iowa, United States
Posts: 1,888
Rep Power: 25
alberto will become famous soon enoughalberto will become famous soon enough
Quote:
Originally Posted by sErik View Post
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?
Info on CFL: http://en.wikipedia.org/wiki/Courant%E2%80%93Friedrichs%E2%80%93Lewy_condition

About your case, it would be useful to know some more details on the case and the numerical setup (fvSchemes, essentially).

Best,
__________________
Alberto

GeekoCFD - A free distribution based on openSUSE 64 bit with CFD tools, including OpenFOAM. Available as live DVD/USB, hard drive image and virtual image.
GeekoCFD 32bit - The 32bit edition of GeekoCFD.
GeekoCFD text mode - A smaller version of GeekoCFD, text-mode only, with only OpenFOAM. Available in a variety of virtual formats.

Last edited by alberto; November 23, 2009 at 19:14. Reason: Corrected link
alberto is offline   Reply With Quote

Old   November 23, 2009, 20:53
Default
  #5
Senior Member
 
akidess's Avatar
 
Anton Kidess
Join Date: May 2009
Location: Delft, Netherlands
Posts: 919
Rep Power: 16
akidess will become famous soon enough
Quote:
Originally Posted by sErik View Post
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?
Changing the initial speed will not do a lot to fix your problem. A Courant number of ~e+52 is unphysical anyways.. As I said, check your boundary conditions and physical parameters, then come back here with more information on the problem (like Alberto said, fvSchemes would be good to look at).
akidess is offline   Reply With Quote

Old   November 24, 2009, 04:33
Default
  #6
Member
 
Join Date: Nov 2009
Location: Munich
Posts: 43
Rep Power: 7
sErik is on a distinguished road
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:
FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "system";
object fvSchemes;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

ddtSchemes
{
default steadyState;
}

gradSchemes
{
default Gauss linear;
}

divSchemes
{
default none;
div(phi,U) Gauss upwind;
div(phi,T) Gauss upwind;
div(phi,k) Gauss upwind;
div(phi,epsilon) Gauss upwind;
div(phi,R) Gauss upwind;
div(R) Gauss linear;
div((nuEff*dev(grad(U).T()))) Gauss linear;
}

laplacianSchemes
{
default none;
laplacian(nuEff,U) Gauss linear corrected;
laplacian((1|A(U)),p) Gauss linear corrected;
laplacian(kappaEff,T) Gauss linear corrected;
laplacian(DkEff,k) Gauss linear corrected;
laplacian(DepsilonEff,epsilon) Gauss linear corrected;
laplacian(DREff,R) Gauss linear corrected;
}

interpolationSchemes
{
default linear;
}

snGradSchemes
{
default corrected;
}

fluxRequired
{
default no;
p ;
}
I've just copied the file from the tutorial. I'm not so sure about the impact/meaning of every entry.

There are the initial conditions for U:
Quote:
dimensions [0 1 -1 0 0 0 0];

internalField uniform (0 0 0);

boundaryField
{
inlet
{
type fixedValue;
referenceField uniform (0.1 0 0);
value uniform (0.1 0 0);

}

outlet
{
type inletOutlet;
inletValue uniform (0 0 0);
value uniform (0 0 0);
}

frontAndBack
{
type fixedValue;
value uniform (0 0 0);
}

lowerWall
{
type fixedValue;
value uniform (0 0 0);
}

upperWall
{
type fixedValue;
value uniform (0 0 0);
}

Rohrelement_NASTRAN
{
type fixedValue;
value uniform (0 0 0);
}

}
And this one for p:
Quote:
inlet
{
type zeroGradient;
}

outlet
{
type fixedValue;
value uniform 0;
}

frontAndBack
{
type zeroGradient;
}

lowerWall
{
type zeroGradient;
}

upperWall
{
type zeroGradient;
}

Rohrelement_NASTRAN
{
type zeroGradient;
}

}
And here are the boundary conditions:
Quote:
6
(
frontAndBack
{
type wall;
nFaces 266;
startFace 49933;
}
inlet
{
type patch;
nFaces 154;
startFace 50199;
}
outlet
{
type patch;
nFaces 367;
startFace 50353;
}
lowerWall
{
type wall;
nFaces 100;
startFace 50720;
}
upperWall
{
type wall;
nFaces 100;
startFace 50820;
}
Rohrelement_NASTRAN
{
type wall;
nFaces 3541;
startFace 50920;
}
)
To be honest, I'm not sure about all the effects of the "type-statements" like, "wall" or "patch" in the boundary conditions or "patch", "inletOutlet" for the initial conditions - or other statements for the cases. Wwhich/how many statements are there acually, with what kind of consequences? Is there a description or something like that, where I can figure out the effects on the solution?

Sorry for the long post.

Last edited by sErik; November 24, 2009 at 06:07.
sErik is offline   Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Compile problem ivanyao OpenFOAM Running, Solving & CFD 1 October 12, 2012 10:31
Problem with compile the setParabolicInlet ivanyao OpenFOAM Running, Solving & CFD 6 September 5, 2008 21:50
Compiling problems with hello worldC fw407 OpenFOAM Installation 21 January 6, 2008 18:38
DecomposePar links against liblamso0 with OpenMPI jens_klostermann OpenFOAM Bugs 11 June 28, 2007 18:51
user subroutine error CFDUSER CFX 2 December 9, 2006 07:31


All times are GMT -4. The time now is 14:44.