[Mojtaba.a]

Hi.
I am using buoyantSimpleFoam for a simple HVAC system containing 4 air inlet on the ceiling and various forms of air outlet on the wall. There are 5 boxes in the room as a model for humans. there is a lamp producing a known amount of heat.
When i run the simulation after 3 iterations I got this error message:

/*---------------------------------------------------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.0.1 |
| \\ / A nd | Web: www.OpenFOAM.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
Build : 2.0.1
Exec : buoyantSimpleFoam
Date : Jul 08 2012
Time : 17:03:33
Host : mojtaba-HP-Pavilion-dv5-Notebook-PC
PID : 25666
Case : /home/mojtaba/OpenFOAM/mojtaba-2.0.1/run/6_case1/RAS
nProcs : 1
sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster
allowSystemOperations : Disallowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create mesh for time = 0


Reading g
Reading thermophysical properties

Selecting thermodynamics package hPsiThermo<pureMixture<constTransport<specieThermo <hConstThermo<perfectGas>>>>>
Reading field U

Reading/calculating face flux field phi

Creating turbulence model

Selecting RAS turbulence model kEpsilon
kEpsilonCoeffs
{
Cmu 0.09;
C1 1.44;
C2 1.92;
C3 -0.33;
sigmak 1;
sigmaEps 1.3;
Prt 1;
}

Calculating field g.h

Reading field p_rgh


SIMPLE: convergence criteria
field p_rgh tolerance 0.01
field U tolerance 0.001
field h tolerance 0.001
field "(k|epsilon|omega)" tolerance 0.001


Starting time loop

Time = 0.01

DILUPBiCG: Solving for Ux, Initial residual = 1, Final residual = 0.00330151, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 1, Final residual = 0.0046823, No Iterations 1
DILUPBiCG: Solving for Uz, Initial residual = 1, Final residual = 0.00350567, No Iterations 1
DILUPBiCG: Solving for h, Initial residual = 1, Final residual = 1.39886e-06, No Iterations 1
DICPCG: Solving for p_rgh, Initial residual = 0.971915, Final residual = 0.00889702, No Iterations 33
time step continuity errors : sum local = 3.10455, global = -3.6689e-16, cumulative = -3.6689e-16
rho max/min : 1.3434 0.990723
DILUPBiCG: Solving for epsilon, Initial residual = 0.971289, Final residual = 0.0619395, No Iterations 1
DILUPBiCG: Solving for k, Initial residual = 1, Final residual = 0.033557, No Iterations 1
ExecutionTime = 1.21 s ClockTime = 1 s

Time = 0.02

DILUPBiCG: Solving for Ux, Initial residual = 0.127444, Final residual = 0.000790034, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 0.0886407, Final residual = 0.000657201, No Iterations 1
DILUPBiCG: Solving for Uz, Initial residual = 0.113225, Final residual = 0.000845678, No Iterations 1
DILUPBiCG: Solving for h, Initial residual = 0.435941, Final residual = 0.00537677, No Iterations 3
DICPCG: Solving for p_rgh, Initial residual = 1, Final residual = 0.00945094, No Iterations 638
time step continuity errors : sum local = 0.518813, global = -2.86768e-16, cumulative = -6.53658e-16
rho max/min : 1.97732e+10 -9.88007e+09
DILUPBiCG: Solving for epsilon, Initial residual = 0.605293, Final residual = 0.0131068, No Iterations 1
DILUPBiCG: Solving for k, Initial residual = 1, Final residual = 0.014658, No Iterations 2
ExecutionTime = 4.24 s ClockTime = 4 s

Time = 0.03

DILUPBiCG: Solving for Ux, Initial residual = 0.189338, Final residual = 0.00230566, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 0.153492, Final residual = 0.00222301, No Iterations 1
DILUPBiCG: Solving for Uz, Initial residual = 0.0758416, Final residual = 0.00080249, No Iterations 1
DILUPBiCG: Solving for h, Initial residual = 0.0792621, Final residual = 0.000120424, No Iterations 1


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

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/mojtaba/OpenFOAM/OpenFOAM-2.0.1/src/thermophysicalModels/specie/lnInclude/specieThermoI.H at line 67.

FOAM aborting

#0 Foam::error:: printStack(Foam::Ostream&) in "/home/mojtaba/OpenFOAM/OpenFOAM-2.0.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#1 Foam::error::abort() in "/home/mojtaba/OpenFOAM/OpenFOAM-2.0.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#2 Foam::hPsiThermo<Foam:: pureMixture<Foam::constTransport<Foam::specieTherm o<Foam::hConstThermo<Foam:: perfectGas> > > > >::calculate() in "/home/mojtaba/OpenFOAM/OpenFOAM-2.0.1/platforms/linux64GccDPOpt/lib/libbasicThermophysicalModels.so"
#3 Foam::hPsiThermo<Foam:: pureMixture<Foam::constTransport<Foam::specieTherm o<Foam::hConstThermo<Foam:: perfectGas> > > > >::correct() in "/home/mojtaba/OpenFOAM/OpenFOAM-2.0.1/platforms/linux64GccDPOpt/lib/libbasicThermophysicalModels.so"
#4
in "/home/mojtaba/OpenFOAM/OpenFOAM-2.0.1/platforms/linux64GccDPOpt/bin/buoyantSimpleFoam"
#5 __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
#6
in "/home/mojtaba/OpenFOAM/OpenFOAM-2.0.1/platforms/linux64GccDPOpt/bin/buoyantSimpleFoam"
Aborted

Any helps would be appreciated.

[tian]

Hi,

check your boundary setup at time 0. It seems to be wrong.

Bye
Tian

[Mojtaba.a]

Originally Posted by tian

Hi,

check your boundary setup at time 0. It seems to be wrong.

Bye
Tian

Hi Tian,
Thanks for yout reply. my boundary conditions at time 0 are as follows:

For Pressure:

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.0.1 |
| \\ / A nd | Web: www.OpenFOAM.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

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

internalField uniform 35e4;

boundaryField
{
wall
{
type calculated;
value $internalField;
}

air-inlet
{
type fixedValue;
value 2e5;
}

out_flow
{
type calculated;
value $internalField;
}

patient
{
type calculated;
value $internalField;
}

staff4
{
type calculated;
value $internalField;
}

staff3
{
type calculated;
value $internalField;
}

staff2
{
type calculated;
value $internalField;
}

staff1
{
type calculated;
value $internalField;
}

back_light
{
type calculated;
value $internalField;
}

light
{
type calculated;
value $internalField;
}

}

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

For Velocity:

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.0.1 |
| \\ / A nd | Web: www.OpenFOAM.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volVectorField;
object U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

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

internalField uniform (0 0 0);

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

air-inlet
{
type turbulentInlet;
referenceField uniform (0 -1 0);
fluctuationScale (0.01 0.01 0.01);
value uniform (0 -1 0);
}

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

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

staff4
{
type fixedValue;
value uniform (0 0 0);
}

staff3
{
type fixedValue;
value uniform (0 0 0);
}

staff2
{
type fixedValue;
value uniform (0 0 0);
}

staff1
{
type fixedValue;
value uniform (0 0 0);
}

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

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

}

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

For Temperature:

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.0.1 |
| \\ / A nd | Web: www.OpenFOAM.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object T;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions [0 0 0 1 0 0 0];

internalField uniform 300;

boundaryField
{
wall
{
type fixedValue;
value uniform 298;
}

air-inlet
{
type fixedValue;
value uniform 293;
}

out_flow
{
type fixedValue;
value uniform 293;
}

patient
{
type fixedValue;
value uniform 307;
}

staff4
{
type fixedValue;
value uniform 307;
}

staff3
{
type fixedValue;
value uniform 307;
}

staff2
{
type fixedValue;
value uniform 307;
}

staff1
{
type fixedValue;
value uniform 307;
}

back_light
{
type fixedValue;
value uniform 298;
}
light
{
type fixedValue;
value uniform 298;
}
}

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

Model image:

[tian]

Hi,

T: out_flow
type fixedValue;
value uniform 293;
-- > Should be "zeroGradient" ?

P:
internalField uniform 35e4; ?
Is it not to much for a normal room?

air-inlet should be "zeroGradient" and out_flow also as fixedValue?

Bye
Tian

[Mojtaba.a]

Originally Posted by tian

air-inlet should be "zeroGradient" and out_flow also as fixedValue?

Do you mean I apply these changes in pressure 0 conditions? or all other conditions too?
And what do i assign as value to out_flow when I change it to fixedValue?

[Mojtaba.a]

Originally Posted by tian

Hi,

T: out_flow
type fixedValue;
value uniform 293;
-- > Should be "zeroGradient" ?

P:
internalField uniform 35e4; ?
Is it not to much for a normal room?

air-inlet should be "zeroGradient" and out_flow also as fixedValue?

Bye
Tian

Final initial conditions are now as follows:

For Pressure:

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.0.1 |
| \\ / A nd | Web: www.OpenFOAM.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

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

internalField uniform 1e5;

boundaryField
{
wall
{
type calculated;
value $internalField;
}

air-inlet
{
type zeroGradient;
}

out_flow
{
type fixedValue;
value 1e5;
}

patient
{
type calculated;
value $internalField;
}

staff4
{
type calculated;
value $internalField;
}

staff3
{
type calculated;
value $internalField;
}

staff2
{
type calculated;
value $internalField;
}

staff1
{
type calculated;
value $internalField;
}

back_light
{
type calculated;
value $internalField;
}

light
{
type calculated;
value $internalField;
}

}

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

For Temperature:

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.0.1 |
| \\ / A nd | Web: www.OpenFOAM.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object T;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions [0 0 0 1 0 0 0];

internalField uniform 300;

boundaryField
{
wall
{
type fixedValue;
value uniform 298;
}

air-inlet
{
type fixedValue;
value uniform 293;
}

out_flow
{
type zeroGradient;
}

patient
{
type fixedValue;
value uniform 307;
}

staff4
{
type fixedValue;
value uniform 307;
}

staff3
{
type fixedValue;
value uniform 307;
}

staff2
{
type fixedValue;
value uniform 307;
}

staff1
{
type fixedValue;
value uniform 307;
}

back_light
{
type fixedValue;
value uniform 298;
}
light
{
type fixedValue;
value uniform 298;
}
}

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

For P_rgh:

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.0.1 |
| \\ / A nd | Web: www.OpenFOAM.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object p_rgh;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

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

internalField uniform 1e5;

boundaryField
{
wall
{
type buoyantPressure;
value $internalField;
}

air-inlet
{
type buoyantPressure;
value $internalField;
}

out_flow
{
type buoyantPressure;
value $internalField;
}

patient
{
type buoyantPressure;
value $internalField;
}

staff4
{
type buoyantPressure;
value $internalField;
}

staff3
{
type buoyantPressure;
value $internalField;
}

staff2
{
type buoyantPressure;
value $internalField;
}

staff1
{
type buoyantPressure;
value $internalField;
}

back_light
{
type buoyantPressure;
value $internalField;
}
light
{
type buoyantPressure;
value $internalField;
}
}

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

For Velocity:

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.0.1 |
| \\ / A nd | Web: www.OpenFOAM.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volVectorField;
object U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

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

internalField uniform (0 0 0);

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

air-inlet
{
type turbulentInlet;
referenceField uniform (0 -1 0);
fluctuationScale (0.01 0.01 0.01);
value uniform (0 -1 0);
}

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

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

staff4
{
type fixedValue;
value uniform (0 0 0);
}

staff3
{
type fixedValue;
value uniform (0 0 0);
}

staff2
{
type fixedValue;
value uniform (0 0 0);
}

staff1
{
type fixedValue;
value uniform (0 0 0);
}

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

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

}

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

But i face the same error message again.

[himanshu28]

Originally Posted by Mojtaba.a

Final initial conditions are now as follows:

For Pressure:


For Temperature:


For P_rgh:


For Velocity:


But i face the same error message again.

Were you able to solve the problem. I am doing pretty much the same kind of the problem, and getting the same divergence.

Thank you

[jaydeep]

As a thumb rule - you should not use explicit boundary conditions to Pressure in cht solvers.

p = p_rgh + rho*gh;

This is how pressure is handled in the solver.


Secondly - for free boundaries on pressure (atmospheric) ideally you should use totalPressure in p_rgh (updated version of buoyantPressure), although I have experienced instability with totalPressure and discovered zeroGradient to be working quite well.

Next - for inlet conditions, unless specified, I'd recommend "zeroGradient" at both inlets and outlets in velocity boundary condition.