[sasanghomi]

Hi Dear Foamers,

I have a problem about using rhocentralFoam. I uploaded a simple case. I want to simulate the compressible fluid flow around an object, But the case diverges very soon.
Please take a look at my simple case and please guide me.

Error text :

--> FOAM FATAL ERROR: 
Maximum number of iterations exceeded

    From function thermo<Thermo, Type>::T(scalar f, scalar T0, scalar (thermo<Thermo, Type>::*F)(const scalar) const, scalar (thermo<Thermo, Type>::*dFdT)(const scalar) const, scalar (thermo<Thermo, Type>::*limit)(const scalar) const) const
    in file /home/opencfd/OpenFOAM/OpenFOAM-2.2.2/src/thermophysicalModels/specie/lnInclude/thermoI.H at line 76.

FOAM aborting

#0  Foam::error::printStack(Foam::Ostream&) in "/opt/openfoam222/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#1  Foam::error::abort() in "/opt/openfoam222/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#2  Foam::species::thermo<Foam::hConstThermo<Foam::perfectGas<Foam::specie> >, Foam::sensibleInternalEnergy>::T(double, double, double, double (Foam::species::thermo<Foam::hConstThermo<Foam::perfectGas<Foam::specie> >, Foam::sensibleInternalEnergy>::*)(double, double) const, double (Foam::species::thermo<Foam::hConstThermo<Foam::perfectGas<Foam::specie> >, Foam::sensibleInternalEnergy>::*)(double, double) const, double (Foam::species::thermo<Foam::hConstThermo<Foam::perfectGas<Foam::specie> >, Foam::sensibleInternalEnergy>::*)(double) const) const in "/opt/openfoam222/platforms/linux64GccDPOpt/lib/libfluidThermophysicalModels.so"
#3  Foam::hePsiThermo<Foam::psiThermo, Foam::pureMixture<Foam::constTransport<Foam::species::thermo<Foam::hConstThermo<Foam::perfectGas<Foam::specie> >, Foam::sensibleInternalEnergy> > > >::calculate() in "/opt/openfoam222/platforms/linux64GccDPOpt/lib/libfluidThermophysicalModels.so"
#4  Foam::hePsiThermo<Foam::psiThermo, Foam::pureMixture<Foam::constTransport<Foam::species::thermo<Foam::hConstThermo<Foam::perfectGas<Foam::specie> >, Foam::sensibleInternalEnergy> > > >::correct() in "/opt/openfoam222/platforms/linux64GccDPOpt/lib/libfluidThermophysicalModels.so"
#5  
 in "/opt/openfoam222/platforms/linux64GccDPOpt/bin/rhoCentralFoam"
#6  __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
#7  
 in "/opt/openfoam222/platforms/linux64GccDPOpt/bin/rhoCentralFoam"
Aborted (core dumped)

the velocity and pressure boundary conditions :

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.2.2                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volVectorField;
    location    "0";
    object      U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

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

internalField   uniform (173.5943547 0 0);

boundaryField
{
  inlet

  {
    type freestream;
    freestreamValue uniform (173.5943547 0  0); 
  }
  body

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


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

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.2.2                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volScalarField;
    location    "0";
    object      p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

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

internalField   uniform 101325;

boundaryField
{
body

  {
 
   type          zeroGradient;
  
  }

   inlet
  
  {
   type         fixedValue;
   value        uniform 101325;

  }

}


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

Link of my case :
https://mega.co.nz/#!s9BGgD6S!ebEc0x...N75tYYZSPZ3lbM

I appreciate any help from you.
Thanks and best regards,
Sasan.

[lfgmarc]

Hi, in my personal expertise this problem come from with the convergence of the iterative method utilized to calculate temperature from energetic variable. I suggest check your boundary conditions.



Regards,


Felipe

[sasanghomi]

Dear Felipe, Thanks for your reply. Do you have any suggestions about boundary conditions? Is it possible to take a look at my case?

I appreciate your help
Best regards
Sasan.

[lfgmarc]

Hi, Give me some time and I will review your case.

Regards.

[alexeym]

Hi,

I've tried to run your case (ignoring rather interesting BCs) the reason for divergence is rather large initial time step. I've changed it to 1e-9 and everything started running. After several time steps value of dt stabilizes at

Mean and max Courant Numbers = 0.00928758543141 0.200031474414
deltaT = 3.71688375776e-08
Time = 2.90508688931e-06

Also I've decreased tolerances in fvSolution (down to 1e-8).

[sasanghomi]

Hi Alexey

Thank you very much for your guidance. As you said, The initial time step was large. I hope not to occur a new error in my simulation!

Thanks and best regards,
Sasan.