[kishore208]

---------------------------------------------------------------------------*\
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration | Website: https://openfoam.org
\\ / A nd | Version: 8
\\/ M anipulation |
\*---------------------------------------------------------------------------*/
Build : 8-1c9b5879390b
Exec : buoyantSimpleFoam
Date : Apr 09 2022
Time : 12:36:14
Host : "DESKTOP-JC8IQK3"
PID : 456
I/O : uncollated
Case : /mnt/c/users/kishore/desktop/RUN7/Vel3
nProcs : 1
sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster (fileModificationSkew 10)
allowSystemOperations : Allowing user-supplied system call operations

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

Create mesh for time = 0


SIMPLE: No convergence criteria found

Reading thermophysical properties

Selecting thermodynamics package
{
type heRhoThermo;
mixture pureMixture;
transport polynomial;
thermo hPolynomial;
equationOfState icoPolynomial;
specie specie;
energy sensibleEnthalpy;
}

Reading field U

Reading/calculating face flux field phi

Creating turbulence model

Selecting turbulence model type RAS
Selecting RAS turbulence model kOmegaSST
Selecting patchDistMethod meshWave
RAS
{
RASModel kOmegaSST;
turbulence on;
printCoeffs on;
alphaK1 0.85;
alphaK2 1;
alphaOmega1 0.5;
alphaOmega2 0.856;
gamma1 0.555556;
gamma2 0.44;
beta1 0.075;
beta2 0.0828;
betaStar 0.09;
a1 0.31;
b1 1;
c1 10;
F3 false;
}

Creating thermophysical transport model

Selecting thermophysical transport type RAS
Selecting default RAS thermophysical transport model eddyDiffusivity

Reading g

Reading hRef
Calculating field g.h


Reading pRef
Reading field p_rgh

No MRF models present

Selecting radiationModel none
Creating finite volume options from "system/fvOptions"

Selecting finite volume options model type limitTemperature
Source: limitTemperature
- selecting all cells
- selected 2543200 cell(s) with volume 2.015e-06

Starting time loop

Time = 1

DILUPBiCGStab: Solving for Ux, Initial residual = 1, Final residual = 0.00419822, No Iterations 1
DILUPBiCGStab: Solving for Uy, Initial residual = 1, Final residual = 0.00444248, No Iterations 1
DILUPBiCGStab: Solving for Uz, Initial residual = 1, Final residual = 0.00357752, No Iterations 1
DILUPBiCGStab: Solving for h, Initial residual = 1, Final residual = 0.00478165, No Iterations 1
GAMG: Solving for p_rgh, Initial residual = 1, Final residual = 0.00751737, No Iterations 32
GAMG: Solving for p_rgh, Initial residual = 8.81394e-06, Final residual = 7.68281e-08, No Iterations 22
time step continuity errors : sum local = 0.0176287, global = -0.00390632, cumulative = -0.00390632
DILUPBiCGStab: Solving for omega, Initial residual = 0.0037478, Final residual = 3.00244e-05, No Iterations 1
DILUPBiCGStab: Solving for k, Initial residual = 1, Final residual = 0.0113279, No Iterations 1
ExecutionTime = 60.5 s ClockTime = 77 s

Time = 2

DILUPBiCGStab: Solving for Ux, Initial residual = 0.112524, Final residual = 0.00144405, No Iterations 1
DILUPBiCGStab: Solving for Uy, Initial residual = 0.167034, Final residual = 0.000924033, No Iterations 1
DILUPBiCGStab: Solving for Uz, Initial residual = 0.111167, Final residual = 0.00127426, No Iterations 1
DILUPBiCGStab: Solving for h, Initial residual = 0.102918, Final residual = 0.00130717, No Iterations 1
GAMG: Solving for p_rgh, Initial residual = 0.00573194, Final residual = 5.30597e-05, No Iterations 44
GAMG: Solving for p_rgh, Initial residual = 2.55759e-05, Final residual = 2.46088e-07, No Iterations 66
time step continuity errors : sum local = 0.0109902, global = -0.00394915, cumulative = -0.00785548
DILUPBiCGStab: Solving for omega, Initial residual = 0.00301768, Final residual = 1.73589e-05, No Iterations 1
DILUPBiCGStab: Solving for k, Initial residual = 0.274394, Final residual = 0.00308121, No Iterations 1
ExecutionTime = 133.46 s ClockTime = 151 s

Time = 3

DILUPBiCGStab: Solving for Ux, Initial residual = 0.170761, Final residual = 0.00152056, No Iterations 1
DILUPBiCGStab: Solving for Uy, Initial residual = 0.351447, Final residual = 0.00157149, No Iterations 1
DILUPBiCGStab: Solving for Uz, Initial residual = 0.172046, Final residual = 0.00116642, No Iterations 1
DILUPBiCGStab: Solving for h, Initial residual = 0.00237003, Final residual = 2.68847e-05, No Iterations 1
GAMG: Solving for p_rgh, Initial residual = 0.00121354, Final residual = 1.17761e-05, No Iterations 56
GAMG: Solving for p_rgh, Initial residual = 9.42496e-05, Final residual = 8.16498e-07, No Iterations 56
time step continuity errors : sum local = 0.00555272, global = 0.00200445, cumulative = -0.00585103
DILUPBiCGStab: Solving for omega, Initial residual = 0.00259877, Final residual = 1.39329e-05, No Iterations 1
DILUPBiCGStab: Solving for k, Initial residual = 0.155336, Final residual = 0.00181118, No Iterations 1
ExecutionTime = 212.04 s ClockTime = 229 s

Time = 4

DILUPBiCGStab: Solving for Ux, Initial residual = 0.101542, Final residual = 0.00119786, No Iterations 1
DILUPBiCGStab: Solving for Uy, Initial residual = 0.0710866, Final residual = 0.000337654, No Iterations 1
DILUPBiCGStab: Solving for Uz, Initial residual = 0.102877, Final residual = 0.000960946, No Iterations 1
DILUPBiCGStab: Solving for h, Initial residual = 0.0019607, Final residual = 1.66053e-05, No Iterations 1
GAMG: Solving for p_rgh, Initial residual = 0.0106693, Final residual = 0.000105543, No Iterations 53
GAMG: Solving for p_rgh, Initial residual = 2.14117e-05, Final residual = 2.10353e-07, No Iterations 56
time step continuity errors : sum local = 0.00822205, global = -0.00320908, cumulative = -0.00906011
DILUPBiCGStab: Solving for omega, Initial residual = 0.00283719, Final residual = 1.57082e-05, No Iterations 1
DILUPBiCGStab: Solving for k, Initial residual = 0.101548, Final residual = 0.00101239, No Iterations 1
ExecutionTime = 290.88 s ClockTime = 308 s

Time = 5

DILUPBiCGStab: Solving for Ux, Initial residual = 0.351208, Final residual = 0.00193989, No Iterations 1
DILUPBiCGStab: Solving for Uy, Initial residual = 0.414755, Final residual = 0.00179017, No Iterations 1
DILUPBiCGStab: Solving for Uz, Initial residual = 0.35721, Final residual = 0.00201229, No Iterations 1
DILUPBiCGStab: Solving for h, Initial residual = 0.00261952, Final residual = 2.65276e-05, No Iterations 1

From function Foam::scalar Foam::species::thermo<Thermo, Type>::T(Foam::scalar, Foam::scalar, Foam::scalar, Foam::scalar (Foam::species::thermo<Thermo, Type>::*)(Foam::scalar, Foam::scalar) const, Foam::scalar (Foam::species::thermo<Thermo, Type>::*)(Foam::scalar, Foam::scalar) const, Foam::scalar (Foam::species::thermo<Thermo, Type>::*)(Foam::scalar) const, bool) const [with Thermo = Foam::hPolynomialThermo<Foam::icoPolynomial<Foam:: specie> >; Type = Foam::sensibleEnthalpy; Foam::scalar = double; Foam::species::thermo<Thermo, Type> = Foam::species::thermo<Foam::hPolynomialThermo<Foam ::icoPolynomial<Foam::specie> >, Foam::sensibleEnthalpy>]
in file /home/ubuntu/OpenFOAM/OpenFOAM-8/src/thermophysicalModels/specie/lnInclude/thermoI.H at line 70
Energy -> temperature conversion failed to converge:

--> FOAM FATAL ERROR:
Maximum number of iterations exceeded: 100






I am getting this error when I am simulating a channel flow with komegasst turbulence model using buoyantSimpleFoam solver.

[Bloerb]

This is quite a typical crash. Your solver diverged. The crash occurs after solving for h. Hence the ....hPolynomialThermopart inside the error message. After solving for temperature temperature depended properties are updated. You are using a polynomial for some. You might have a polynomial that can lead to negative or unphysical values. For example a polynomial like mu = -400 + T can be negative for T < 400. And negative viscosity isn't really something you can solve with.

This isn't necessarily a problem of the polynomial though. It crashes right in the beginning. You should check the boundary values for turbulence variables like k, omega or epsilon at the inlet. Your mesh quality, etc. Basically initialize your solution better.

[kishore208]

This simulation is working quite well for low Reynolds numbers around 700, but When I am increasing Reynolds number, it is giving this error.
The mesh is completely hexahedral and I already check the quality also.
It must be due to boundary values for turbulence in files(k, omega and epsilon).
How to decide the boundary values in these files?

[Bloerb]

Check the top of this site. There is a Tools button. Under which you'll find a Turbulence Properties calculator. Use that for the internalField initial value. The same equations are used by these boundary conditions:


for k

<patchName>
{
    type        turbulentIntensityKineticEnergyInlet;
    intensity   0.05;
    value       $internalField;
}

for omega

<patchName>
{
    type            turbulentMixingLengthFrequencyInlet;
    mixingLength    1;
    value           $internalField;
}

The lengh scale / mixingLength can be estimated as 0.07*Diameter and the intensity depends on how turbulent your flow is. Maybe 2% to 10%.