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

rhoSimpleFoam

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

Reply
 
LinkBack Thread Tools Display Modes
Old   February 2, 2011, 16:06
Default rhoSimpleFoam
  #1
New Member
 
Join Date: Jan 2011
Posts: 6
Rep Power: 6
aPostrophic is on a distinguished road
Hi,
i have a problem with rhoSimpleFoam(compressible flow over an airfoil). After a few seconds of iteration i get an ERROR because my desity becomes negative. For lower velocities (25 m/s) the solver is working fine.



ILUPBiCG: Solving for Ux, Initial residual = 0.0416817, Final residual = 3.43245e-07, No Iterations 3
DILUPBiCG: Solving for Uy, Initial residual = 0.0547899, Final residual = 7.02575e-07, No Iterations 3
DILUPBiCG: Solving for h, Initial residual = 0.579378, Final residual = 3.346e-06, No Iterations 3
DICPCG: Solving for p, Initial residual = 0.822832, Final residual = 9.23512e-07, No Iterations 217
time step continuity errors : sum local = 0.165649, global = 0.000831612, cumulative = 0.00080585
rho max/min : 1653.12 -529.803
bounding p, min: -2.02969e+08 max: 695295 average: -3.70797e+07
ExecutionTime = 1.62 s ClockTime = 2 s

Time = 22

DILUPBiCG: Solving for Ux, Initial residual = 0.118398, Final residual = 5.61993e-06, No Iterations 3
DILUPBiCG: Solving for Uy, Initial residual = 0.192935, Final residual = 4.42431e-06, No Iterations 3
DILUPBiCG: Solving for h, Initial residual = 0.190434, Final residual = 3.27602e-06, No Iterations 3


Maximum number of iterations exceeded#0 Foam::error:rintStack(Foam::Ostream&) in "/home/++++/OpenFOAM/OpenFOAM-1.6/lib/linux64gcc451DPOpt/libOpenFOAM.so"
#1 Foam::error::abort() at /home/++++/OpenFOAM/OpenFOAM-1.6/src/OpenFOAM/lnInclude/Ostream.H:252
#2 Foam::hPsiThermo<Foam:ureMixture<Foam::constTran sport<Foam::specieThermo<Foam::hConstThermo<Foam:: perfectGas> > > > >::calculate() in "/home/++++/OpenFOAM/OpenFOAM-1.6/lib/linux64gcc451DPOpt/libbasicThermophysicalModels.so"
#3 Foam::hPsiThermo<Foam:ureMixture<Foam::constTran sport<Foam::specieThermo<Foam::hConstThermo<Foam:: perfectGas> > > > >::correct() in "/home/++++/OpenFOAM/OpenFOAM-1.6/lib/linux64gcc451DPOpt/libbasicThermophysicalModels.so"
#4 main at ~/OpenFOAM/++++/applications/myrhoSimpleFoam/hEqn.H:10
#5 __libc_start_main in "/lib64/libc.so.6"
#6 Foam::regIOobject::writeObject(Foam::IOstream::str eamFormat, Foam::IOstream::versionNumber, Foam::IOstream::compressionType) const in "/home/++++OpenFOAM/OpenFOAM-1.6/applications/bin/linux64gcc451DPOpt/myrhoSimpleFoam"


From function specieThermo<thermo>::T(scalar f, scalar T0, scalar (specieThermo<thermo>::*F)(const scalar) const, scalar (specieThermo<thermo>::*dFdT)(const scalar) const) const
in file /home/++++/OpenFOAM/OpenFOAM-1.6/src/thermophysicalModels/specie/lnInclude/specieThermoI.H at line 68.

FOAM aborting





Here are my boundary conditions:

FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object p;
}

dimensions [1 -1 -2 0 0 0 0];

internalField uniform 100000;

boundaryField
{
farfield1
{
type zeroGradient;
}

farfield2
{
type zeroGradient;
}

farfield3
{
type fixedValue;
value $internalField;
}

airfoil
{
type zeroGradient;
}

frontAndBackPlanes
{
type empty;
}
}

// ************************************************** *********************** //


FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object T;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions [0 0 0 1 0 0 0];

internalField uniform 300;




boundaryField
{
farfield1
{
type zeroGradient;
}

farfield2
{
type zeroGradient;
}


farfield3
{
type fixedValue;
value $internalField;

}

airfoil
{
type zeroGradient;
}

frontAndBackPlanes
{
type empty;
}
}


FoamFile
{
version 2.0;
format ascii;
class volVectorField;
object U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions [0 1 -1 0 0 0 0];

internalField uniform (104 2 0);

boundaryField
{
farfield1
{
type freestream;
value $internalField;

farfield2
{
type freestream;
value $internalField;
}

farfield3
{
type freestream;
value $internalField;
}

airfoil
{
type zeroGradient;
}

frontAndBackPlanes
{
type empty;
}
}

I have switched off the Turbulence model and I use

thermoType hPsiThermo<pureMixture<constTransport<specieThermo <hConstThermo<perfectGas>>>>>;

mixture air 1 28.9 1007 0 1.84e-05 0.7;

Does anybody know what i can do?
aPostrophic is offline   Reply With Quote

Old   February 3, 2011, 03:21
Default
  #2
Senior Member
 
Alberto Passalacqua
Join Date: Mar 2009
Location: Ames, Iowa, United States
Posts: 1,894
Rep Power: 26
alberto will become famous soon enoughalberto will become famous soon enough
I would:

- check relaxation factors
- check the mesh
- try with first-order upwind if you use second order schemes

Best,
__________________
Alberto Passalacqua

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.
OpenQBMM - An open-source implementation of quadrature-based moment methods
alberto 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
Switching from simpleFoam to rhoSimpleFoam sebastian OpenFOAM 11 January 7, 2015 05:32
transsonic nozzle with rhoSimpleFoam Unseen OpenFOAM Running, Solving & CFD 7 April 16, 2014 03:38
Question about rhoSimpleFoam "if (transonic)" universez OpenFOAM 4 April 17, 2010 10:21
Problem with rhoSimpleFoam mecbe2002 OpenFOAM 3 April 11, 2010 00:54
RhoSimpleFoam FoamX spv24 OpenFOAM Running, Solving & CFD 1 July 21, 2008 10:29


All times are GMT -4. The time now is 13:33.