[Raza Javed]

Originally Posted by alexeym

Usually I use zero gradient outlet boundary conditions for turbulence. For inlet it's turbulentIntensityKineticEnergyInlet and similar patch types (see $FOAM_SRC/finiteVolume/fields/fvPatchFields/derived, $FOAM_SRC/turbulenceModels/incompressible/RAS/derivedFvPatchFields folders for names or you can use fixedValue estimated using http://www.cfd-online.com/Wiki/Turbu...ary_conditions). And for walls - yes - wall functions.

Hi Alexeym,


I am also modelling a Turbulent flow in a chtMultiRegionSimpleFoam, with Openfoam version of 4.1


In my geometry, I have multiple region, from them, one is fluid region.


before I was running the laminar flow and it worked fine for me.


Now I changed to turbulent, But I am making mistakes in boundary conditions for Turbulent flow.


I have the following boundary conditions in the fluid region


Temperature(T):

T
{
    internalField   uniform 300;

    boundaryField
    {
        inlet
        {
            type            fixedValue;
            value           $internalField;
            
        }

        outlet
        {
            type            zeroGradient;
            value           $internalField;

        }

        "fluid_to_box"
        {
            type            compressible::turbulentTemperatureCoupledBaffleMixed;
            Tnbr            T;
            kappaMethod     fluidThermo;
            value           uniform 300;
        }
    }
}

Velocity (U)

U
{
    internalField   uniform (0 0 0);

    boundaryField
    {
        inlet
        {
            type            fixedValue;
            value           uniform (0 0 -1.33);
        }

        outlet
        {
            type            zeroGradient;
        }
        "fluid_to_box"
        {
            type            noSlip;
        }
    }
}

Epsilon

epsilon
{
    internalField   uniform 0.01;

    boundaryField
    {
        inlet
        {
            type            fixedValue;
            value           uniform 0.01;
        }

        outlet
        {
            type            zeroGradient
            //value           uniform 0;
        }

        "fluid_to_box"
        {
            type            epsilonWallFunction;
            value           uniform 0.01;
        }
    }
}

k

k
{
    internalField   uniform 0.1;

    boundaryField
    {
        inlet
        {
            type            fixedValue
            value           uniform 0.1;
        }

        outlet
        {
            type            zeroGradient;
            //value           uniform 0;
        }

        "fluid_to_box"
        {
            type            kqRWallFunction;
            value           uniform 0.1;
        }
    }
}

p_rgh (I have no idea about the significance of this parameter)

p_rgh
{
    internalField   uniform 0;

    boundaryField
    {
        inlet
        {
            type            zeroGradient;
            value           uniform 0;
        }

        outlet
        {
            type            fixedValue;
            value           uniform 0;
        }

        ".*"
        {
            type            fixedFluxPressure;
            value           uniform 0;
        }
    }
}

p

p
{
    internalField   uniform 0;

    boundaryField
    {
        ".*"
        {
            type            calculated;
            value           uniform 0;
        }
    }
}

alphat

alphat
{
    internalField   uniform 0;

    boundaryField
    {
        inlet
        {
            type            calculated;//fixedValue;
            value           uniform 0;
        }

        outlet
        {
            type            calculated;
            value           uniform 0;
        }

        "fluid_to_box"
        {
            type            compressible::alphatJayatillekeWallFunction;
            value           uniform 0;
        }

    }
}

nut

nut
{
    internalField   uniform 0;

    boundaryField
    {
        inlet
        {
            type            calculated;
            value           uniform 0;
        }

        outlet
        {
            type            calculated;
            value           uniform 0;
        }

        "fluid_to_box"
        {
            type            nutkWallFunction;
            value           uniform 0;
        }
    }
}

with these boundary conditions, I am getting the following error:

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

    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) const [with Thermo = Foam::hConstThermo<Foam::rhoConst<Foam::specie> >; Type = Foam::sensibleEnthalpy; Foam::scalar = double; Foam::species::thermo<Thermo, Type> = Foam::species::thermo<Foam::hConstThermo<Foam::rhoConst<Foam::specie> >, Foam::sensibleEnthalpy>]
    in file /home/ubuntu/OpenFOAM/OpenFOAM-4.1/src/thermophysicalModels/specie/lnInclude/thermoI.H at line 66.

FOAM aborting

#0  Foam::error::printStack(Foam::Ostream&) at ??:?
#1  Foam::error::abort() at ??:?
#2  Foam::heRhoThermo<Foam::rhoThermo, Foam::pureMixture<Foam::constTransport<Foam::species::thermo<Foam::hConstThermo<Foam::rhoConst<Foam::specie> >, Foam::sensibleEnthalpy> > > >::calculate() at ??:?
#3  Foam::heRhoThermo<Foam::rhoThermo, Foam::pureMixture<Foam::constTransport<Foam::species::thermo<Foam::hConstThermo<Foam::rhoConst<Foam::specie> >, Foam::sensibleEnthalpy> > > >::correct() at ??:?
#4  ? at ??:?
#5  __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
#6  ? at ??:?
Aborted (core dumped)

I don't know that which boundary conditions are compatible for turbulence modelling.



And you can see in the log below, that the temperature of the fluid region and the box region is very high. May be the boundary between fluid and the box should have some other boundary conditions for Temperature

Time = 0.1


Solving for fluid region fluid
DILUPBiCG:  Solving for Ux, Initial residual = 1, Final residual = 0.06453224, No Iterations 1
DILUPBiCG:  Solving for Uy, Initial residual = 1, Final residual = 0.06697346, No Iterations 1
DILUPBiCG:  Solving for Uz, Initial residual = 1, Final residual = 0.0204871, No Iterations 2
DILUPBiCG:  Solving for h, Initial residual = 0.9999975, Final residual = 0.02059882, No Iterations 2
Min/max T:300 300
GAMG:  Solving for p_rgh, Initial residual = 1, Final residual = 0.007092764, No Iterations 8
time step continuity errors : sum local = 0.01886675, global = -0.001468588, cumulative = -0.001468588
Min/max rho:2 2
DILUPBiCG:  Solving for epsilon, Initial residual = 0.4395933, Final residual = 6.211001e-05, No Iterations 1
DILUPBiCG:  Solving for k, Initial residual = 1, Final residual = 0.02989314, No Iterations 2

Solving for solid region box
DICPCG:  Solving for h, Initial residual = 0.9627409, Final residual = 0.04983224, No Iterations 2
Min/max T:300 300

Solving for solid region plate1
DICPCG:  Solving for h, Initial residual = 0.5559331, Final residual = 0.04337605, No Iterations 1
Min/max T:300 300

Solving for solid region plate2
DICPCG:  Solving for h, Initial residual = 0.5630651, Final residual = 0.04835675, No Iterations 1
Min/max T:300 300

Solving for solid region plate3
DICPCG:  Solving for h, Initial residual = 0.5485297, Final residual = 0.04496288, No Iterations 1
Min/max T:300 300

Solving for solid region hot1
DICPCG:  Solving for h, Initial residual = 1, Final residual = 0.006312796, No Iterations 2
Min/max T:300 300.0017

Solving for solid region hot2
DICPCG:  Solving for h, Initial residual = 1, Final residual = 0.006366066, No Iterations 2
Min/max T:300 300.0017

Solving for solid region hot3
DICPCG:  Solving for h, Initial residual = 1, Final residual = 0.006641834, No Iterations 2
Min/max T:300 300.0016
ExecutionTime = 0.26 s  ClockTime = 0 s

Time = 0.2


Solving for fluid region fluid
DILUPBiCG:  Solving for Ux, Initial residual = 0.9997316, Final residual = 0.08241705, No Iterations 2
DILUPBiCG:  Solving for Uy, Initial residual = 0.9999182, Final residual = 0.07499477, No Iterations 2
DILUPBiCG:  Solving for Uz, Initial residual = 0.999995, Final residual = 0.05218458, No Iterations 2
DILUPBiCG:  Solving for h, Initial residual = 1, Final residual = 0.04647918, No Iterations 2
Min/max T:-2973288 1662999
GAMG:  Solving for p_rgh, Initial residual = 0.1649963, Final residual = 0.0009814857, No Iterations 6
time step continuity errors : sum local = 19514.56, global = 1518.633, cumulative = 1518.632
Min/max rho:2 2
DILUPBiCG:  Solving for epsilon, Initial residual = 0.9999721, Final residual = 2.415036e-09, No Iterations 1
DILUPBiCG:  Solving for k, Initial residual = 0.9999915, Final residual = 0.06723203, No Iterations 2

Solving for solid region box
DICPCG:  Solving for h, Initial residual = 1, Final residual = 0.04582189, No Iterations 2
Min/max T:-83945.88 100327.4

Solving for solid region plate1
DICPCG:  Solving for h, Initial residual = 1, Final residual = 0.02336527, No Iterations 2
Min/max T:299.9994 300.0009

Solving for solid region plate2
DICPCG:  Solving for h, Initial residual = 1, Final residual = 0.02405056, No Iterations 2
Min/max T:299.9985 300.0009

Solving for solid region plate3
DICPCG:  Solving for h, Initial residual = 1, Final residual = 0.02425757, No Iterations 2
Min/max T:299.9999 300.0009

Solving for solid region hot1
DICPCG:  Solving for h, Initial residual = 0.8451226, Final residual = 0.005571809, No Iterations 2
Min/max T:300.0004 300.0031

Solving for solid region hot2
DICPCG:  Solving for h, Initial residual = 0.8459859, Final residual = 0.005386573, No Iterations 2
Min/max T:300.0005 300.003

Solving for solid region hot3
DICPCG:  Solving for h, Initial residual = 0.8490941, Final residual = 0.005782687, No Iterations 2
Min/max T:300.0005 300.003
ExecutionTime = 0.33 s  ClockTime = 0 s

Time = 0.3


Solving for fluid region fluid
DILUPBiCG:  Solving for Ux, Initial residual = 0.6319537, Final residual = 0.05386873, No Iterations 1
DILUPBiCG:  Solving for Uy, Initial residual = 0.5952541, Final residual = 0.03315473, No Iterations 1
DILUPBiCG:  Solving for Uz, Initial residual = 0.6117686, Final residual = 0.03323316, No Iterations 1
DILUPBiCG:  Solving for h, Initial residual = 0.4954686, Final residual = 0.02977654, No Iterations 1

Can you please guide me through this problem.


Thank you

[Owais Shabbir]

Hi Raza,

Following could be possible places to find error:
1. Regarding the values of epsilon, k and omega, are you calculating it yourself or you taking it from somewhere?
2. Thermophysicalproperties of each region
3. Set your p to 1e5 instaed of 0
4. Your rho in the solver log is constant at 2 2, is your fluid air or water?
5. What are plate1, plate2, plate3? It seems like you have more than one region.

Could you share your case, so I can have a better look at it?

Regarding your problem of importing alphat is easy. If you are missing any file for your developed case, you can always take it from a tutorial or sometimes the website github has it.
Just copy paste it and change the boundary conditions and internalField according to your geometry and case.


OS

[miragemobile]

Here is an example alphat subdictinary for you. You'll still need the OpenFOAM header at the top.

alphat
{
  internalField   uniform 0;

  boundaryField
  {
    b1
    {
      type            fixedValue;
      value           $internalField;

    }
    b2
    {
      type            zeroGradient;
    }
    b3
    {
      type            compressible::alphatWallFunction;
      Prt             0.85;
      value           uniform 0;
    }
    b4
    {
      type            compressible::alphatWallFunction;
      Prt             0.85;
      value           uniform 0;
    }
    b5
    {
      type            symmetry;
    }
  }
}